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Chapter 16. The java.net PackageThe java.net package provides a powerful and flexible infrastructure for networking. Figure 16-1 and Figure 16-2 show the class hierarchy for this package. Many of the classes in this package are part of the networking infrastructure and are not used by normal applications; these complicated classes can make the package a difficult one to understand. In this overview, I describe only the classes an application might normally use. Figure 16-1. The classes of the java.net packageFigure 16-2. The exceptions of the java.net packageThe URL class represents an Internet uniform resource locator (URL). It provides a very simple interface to networking: the object referred to by the URL can be downloaded with a single call, or streams may be opened to read from or write to the object. At a slightly more complex level, a URLConnection object can be obtained from a given URL object. The URLConnection class provides additional methods that allow you to work with URLs in more sophisticated ways. If you want to do more than simply download an object referenced by a URL, you can do your own networking with the Socket class. This class allows you to connect to a specified port on a specified Internet host and read and write data using the InputStream and OutputStream classes of the java.io package. If you want to implement a server to accept connections from clients, you can use the related ServerSocket class. Both Socket and ServerSocket use the InetAddress address class, which represents an Internet address. The java.net package allows you to do low-level networking with DatagramPacket objects, which may be sent and received over the network through a DatagramSocket object. As of Java 1.1, the package has been extended to include a MulticastSocket class that supports multicast networking.
This abstract class defines a customizable mechanism for requesting and performing password authentication. The static setDefault() method establishes the systemwide Authenticator object to use when password authentication is requested. The implementation can obtain the required authentication information from the user however it wants (e.g., through a text- or a GUI-based interface). setDefault() can be called only once; subsequent calls are ignored. Calling setDefault() requires an appropriate NetPermission. When an application or the Java runtime system requires password authentication (to read the contents of a specified URL, for example), it calls the static requestPasswordAuthentication() method, passing arguments that specify the host and port for which the password is required and a prompt that may be displayed to the user. This method looks up the default Authenticator for the system and calls its getPasswordAuthentication() method. Calling requestPasswordAuthentication() requires an appropriate NetPermission. Authenticator is an abstract class; its default implementation of getPasswordAuthentication() always returns null. To create an Authenticator, you must override this method so that it prompts the user to enter a username and password and returns that information in the form of a PasswordAuthentication object. Your implementation of getPasswordAuthentication() may call the various getRequesting() methods to find who is requesting the password and what the recommended user prompt is.
Passed To: Authenticator.setDefault()
Signals that a socket cannot be bound to a local address and port. This often means that the port is already in use.
Hierarchy: Object-->Throwable(Serializable)-->Exception-->java.io.IOException-->SocketException-->BindException
Signals that a socket cannot be connected to a remote address and port. This means that the remote host can be reached, but is not responding, perhaps because there is no process on that host that is listening on the specified port.
Hierarchy: Object-->Throwable(Serializable)-->Exception-->java.io.IOException-->SocketException-->java.net.ConnectException
This abstract class defines a method that reads data from a URLConnection and returns an object that represents that data. Each subclass that implements this method is responsible for handling a different type of content (i.e., a different MIME type). Applications never create ContentHandler objects directly; they are created, when necessary, by the registered ContentHandlerFactory object. Applications should also never call ContentHandler methods directly; they should call URL.getContent() or URLConnection.getContent() instead. You need to subclass ContentHandler only if you are writing a web browser or similar application that needs to parse and understand some new content type.
Returned By: ContentHandlerFactory.createContentHandler()
This interface defines a method that creates and returns an appropriate ContentHandler object for a specified MIME type. A systemwide ContentHandlerFactory interface may be specified using the URLConnection.setContentHandlerFactory() method. Normal applications never need to use or implement this interface.
Passed To: URLConnection.setContentHandlerFactory()
This class implements a packet of data that may be sent or received over the network through a DatagramSocket. One of the DatagramPacket constructors specifies an array of binary data to be sent with its destination address and port. A packet created with this constructor can then be sent with the send() method of a DatagramSocket. The other DatagramPacket constructor specifies an array of bytes into which data should be received. The receive() method of DatagramSocket waits for data and stores it in a DatagramPacket created in this way. The contents and sender of a received packet can be queried with the DatagramPacket instance methods.
Passed To: DatagramSocket.{receive(), send()}, DatagramSocketImpl.{receive(), send()}, MulticastSocket.send()
This class defines a socket that can receive and send unreliable datagram packets over the network using the UDP protocol. A datagram is a very low-level networking interface: it is simply an array of bytes sent over the network. A datagram does not implement any kind of stream-based communication protocol, and there is no connection established between the sender and the receiver. Datagram packets are called "unreliable" because the protocol does not make any attempt to ensure they arrive or to resend them if they don't. Thus, packets sent through a DatagramSocket are not guaranteed to arrive in the order sent or even to arrive at all. On the other hand, this low-overhead protocol makes datagram transmission very fast. See Socket and URL for higher-level interfaces to networking. If a port is specified when the DatagramSocket is created, that port is used for sending and receiving datagrams; otherwise, the system assigns a port. getLocalPort() returns the port number in use. send() sends a DatagramPacket through the socket. The packet must contain the destination address to which it should be sent. receive() waits for data to arrive at the socket and stores it, along with the address of the sender, in the specified DatagramPacket. close() closes the socket and frees the port for reuse. Once close() has been called, the DatagramSocket should not be used again. Each time a packet is sent or received, the system must perform a security check to ensure that the calling code has permission to send data to or receive data from the specified host. In Java 1.2 and later, if you are sending multiple packets to or receiving multiple packets from a single host, use connect() to specify the host with which you are communicating. This causes the security check to be done a single time, but does not allow the socket to communicate with any other host until disconnect() is called. Use getInetAddress() and getPort() to obtain the host and port, if any, the socket is connected to. setSoTimeout() specifies the number of milliseconds that receive() waits for a packet to arrive before throwing an InterruptedIOException. Specify 0 milliseconds to wait forever. setSendBufferSize() and setReceiveBufferSize() set hints as to the underlying size of the networking buffers.
Subclasses: MulticastSocket
This abstract class defines the methods necessary to implement communication through datagram and multicast sockets. System programmers may create subclasses of this class when they need to implement datagram or multicast sockets in a nonstandard network environment, such as behind a firewall or on a network that uses a nonstandard transport protocol. Normal applications never need to use or subclass this class.
Hierarchy: Object-->DatagramSocketImpl(SocketOptions) Returned By: DatagramSocketImplFactory.createDatagramSocketImpl()
This interface defines a method that creates DatagramSocketImpl objects. You can register an instance of this factory interface with the static setDatagramSocketImplFactory() method of DatagramSocket. Application-level code never needs to use or implement this interface.
Passed To: DatagramSocket.setDatagramSocketImplFactory()
This interface defines a single method that is called to obtain the MIME type of a file based on the name of the file. The fileNameMap field of the URLConnection class refers to an object that implements this interface. The filename-to-file-type map it implements is used by the static URLConnection.guessContentTypeFromName() method.
Passed To: URLConnection.setFileNameMap() Returned By: URLConnection.getFileNameMap()
This class is a specialization of URLConnection. An instance of this class is returned when the openConnection() method is called for a URL object that uses the HTTP protocol. The many constants defined by this class are the status codes returned by HTTP servers. setRequestMethod() specifies what kind of HTTP request is made. The contents of this request must be sent through the OutputStream returned by the getOutputStream() method of the superclass. Once an HTTP request has been sent, getResponseCode() returns the HTTP server's response code as an integer, and getResponseMessage() returns the server's response message. The disconnect() method closes the connection. The static setFollowRedirects() specifies whether URL connections that use the HTTP protocol should automatically follow redirect responses sent by HTTP servers. In order to successfully use this class, you need to understand the details of the HTTP protocol.
Hierarchy: Object-->URLConnection-->HttpURLConnection
This class represents an Internet address and is used when creating DatagramPacket or Socket objects. The class does not have a public constructor function, but instead supports three static methods that return one or more instances of InetAddress. getLocalHost() returns an InetAddress for the local host. getByName() returns the InetAddress of a host specified by name. getAllByName() returns an array of InetAddress objects that represents all the available addresses for a host specified by name. Instance methods are getHostName(), which returns the hostname of an InetAddress, and getAddress(), which returns the Internet IP address as an array of bytes, with the highest-order byte as the first element of the array.
Hierarchy: Object-->InetAddress(Serializable) Passed To: Too many methods to list. Returned By: Authenticator.getRequestingSite(), DatagramPacket.getAddress(), DatagramSocket.{getInetAddress(), getLocalAddress()}, InetAddress.{getAllByName(), getByName(), getLocalHost()}, MulticastSocket.getInterface(), ServerSocket.getInetAddress(), Socket.{getInetAddress(), getLocalAddress()}, SocketImpl.getInetAddress(), URLStreamHandler.getHostAddress() Type Of: SocketImpl.address
This class is a specialized URLConnection that represents a connection to a jar: URL. A jar: URL is a compound URL that includes the URL of a JAR archive and, optionally, a reference to a file or directory within the JAR archive. The jar: URL syntax uses the ! character to separate the pathname of the JAR archive from the filename within the JAR archive. Note that a jar: URL contains a subprotocol that specifies the protocol that retrieves the JAR file itself. For example: jar:http://my.jar.com/my.jar!/ // The whole archive jar:file:/usr/java/lib/my.jar!/com/jar/ // A directory of the archive jar:ftp://ftp.jar.com/pub/my.jar!/com/jar/Jar.class // A file in the archive To obtain a JarURLConnection, define a URL object for a jar: URL, open a connection to it with openConnection(), and cast the returned URLConnection object to a JarURLConnection. The various methods defined by JarURLConnection allow you to read the manifest file of the JAR archive and look up attributes from that manifest for the archive as a whole or for individual entries in the archive. These methods make use of various classes from the java.util.jar package.
Hierarchy: Object-->URLConnection-->JarURLConnection
Signals that an unparseable URL specification has been passed to a method.
Hierarchy: Object-->Throwable(Serializable)-->Exception-->java.io.IOException-->MalformedURLException Thrown By: Too many methods to list.
This subclass of DatagramSocket can send and receive multicast UDP packets. It extends DatagramSocket by adding joinGroup() and leaveGroup() methods to join and leave multicast groups. The IP address specified to these methods should be a valid multicast address in the range of <IP_ADDRESS> to <IP_ADDRESS>. Note that you do not have to join a group to send a packet to a multicast address, but you must join the group to receive packets sent to that address. Note that untrusted code is not allowed to use multicast sockets. MulticastSocket defines a variant send() method that allows you to specify a time-to-live (TTL) value for the packet you send. This value specifies the number of network hops the packet can travel before it expires. You can also set a default TTL for all packets sent though a MulticastSocket with setTimeToLive(), or, prior to Java 1.2, with setTTL().
Hierarchy: Object-->DatagramSocket-->MulticastSocket
This class is a java.security.Permission that represents various permissions required for Java's URL-based networking system. See also SocketPermission, which represents permissions to perform lower-level networking operations. A NetPermission is defined solely by its name; no actions list is required or supported. As of Java 1.2, there are three NetPermission targets defined: "setDefaultAuthenticator" is required to call Authenticator.setDefault(); "requestPasswordAuthentication" to call Authenticator.requestPasswordAuthentication(); and "specifyStreamHandler" to explicitly pass a URLStreamHandler object to the URL() constructor. The target "*" is a wildcard that represents all defined NetPermission targets. System administrators configuring security policies must be familiar with this class and the permissions it represents. System programmers may use this class, but application programmers never need to use it explicitly.
Hierarchy: Object-->java.security.Permission(java.security.Guard,Serializable)-->java.security.BasicPermission(Serializable)-->NetPermission
This exception signals that a socket cannot be connected to a remote host because the host cannot be contacted. Typically, this means that some link in the network between the local machine and the remote host is down or that the host is behind a firewall.
Hierarchy: Object-->Throwable(Serializable)-->Exception-->java.io.IOException-->SocketException-->NoRouteToHostException
This simple immutable class encapsulates a username and a password. The password is stored as a character array rather than as a String object so that the caller can erase the contents of the array after use for increased security. Note that the PasswordAuthentication() constructor clones the specified password character array, but getPassword() returns a reference to the object's internal array. Obtain a PasswordAuthentication object by calling Authenticator.requestPasswordAuthentication().
Returned By: Authenticator.{getPasswordAuthentication(), requestPasswordAuthentication()}
Signals a protocol error in the Socket class.
Hierarchy: Object-->Throwable(Serializable)-->Exception-->java.io.IOException-->ProtocolException Thrown By: HttpURLConnection.setRequestMethod()
This class is used by servers to listen for connection requests from clients. When you create a ServerSocket, you specify the port to listen on. The accept() method begins listening on that port and blocks until a client requests a connection on the port. At that point, accept() accepts the connection, creating and returning a Socket the server can use to communicate with the client. A typical server starts a new thread to handle the communication with the client and calls accept() again to listen for another connection. If you do not want accept() to block for an indefinite amount of time, call setSoTimeout() to specify the number of milliseconds accept() should wait for a connection before throwing an InterruptedIOException.
Returned By: java.rmi.server.RMIServerSocketFactory.createServerSocket(), java.rmi.server.RMISocketFactory.createServerSocket()
This class implements a socket for stream-based interprocess communication over the network. See URL for a higher-level interface to networking and DatagramSocket for a lower-level interface. Use the Socket() constructor to create a socket and connect it to the specified host and port. Once the socket is created, getInputStream() and getOutputStream() return InputStream and OutputStream objects you can use to communicate with the remote host, just as you would use them for file input and output. getInetAddress() and getPort() return the address and port to which the socket is connected. getLocalPort() returns the local port the socket is using. See ServerSocket for information about how a server can listen for and accept connections of this type. When you are done with a Socket, use close() to close it. In Java 1.3, you can also use shutdownInput() and shutdownOutput() to close the input and output communication channels individually. There are several options you can specify for a Socket object to alter its behavior. setSendBufferSize() and setReceiveBufferSize() provide hints to the underlying networking system as to what buffer size is best to use with this socket. setSoTimeout() specifies the number of milliseconds a read() call on the input stream returned by getInputStream() waits for data before throwing an InterruptedIOException. The default value of 0 specifies that the stream blocks indefinitely. setSoLinger() specifies what to do when a socket is closed while there is still data waiting to be transmitted. If lingering is turned on, the close() call blocks for up to the specified number of seconds while attempting to transmit the remaining data. Calling setTcpNoDelay() with an argument of true causes data to be sent through the socket as soon as it is available, instead of waiting for the TCP packet to become more full before sending it. In Java 1.3, use setKeepAlive() to enable or disable the periodic exchange of control messages across an idle socket connection. The keepalive protocol enables a client to determine if its server has crashed without closing the socket and vice versa.
Passed To: ServerSocket.implAccept() Returned By: ServerSocket.accept(), java.rmi.server.RMIClientSocketFactory.createSocket(), java.rmi.server.RMISocketFactory.createSocket()
Signals an exceptional condition while using a socket.
Hierarchy: Object-->Throwable(Serializable)-->Exception-->java.io.IOException-->SocketException Subclasses: BindException, java.net.ConnectException, NoRouteToHostException Thrown By: Too many methods to list.
This abstract class defines the methods necessary to implement communication through sockets. Different subclasses of this class may provide different implementations suitable in different environments (such as behind firewalls). These socket implementations are used by the Socket and ServerSocket classes. Normal applications never need to use or subclass this class.
Hierarchy: Object-->SocketImpl(SocketOptions) Passed To: Socket.Socket(), SocketImpl.accept() Returned By: SocketImplFactory.createSocketImpl()
This interface defines a method that creates SocketImpl objects. SocketImplFactory objects may be registered to create SocketImpl objects for the Socket and ServerSocket classes. Normal applications never need to use or implement this interface.
Passed To: ServerSocket.setSocketFactory(), Socket.setSocketImplFactory()
This interface defines constants that represent low-level BSD Unix-style socket options and methods that set and query the value of those options. In Java 1.2, SocketImpl and DatagramSocketImpl implement this interface. Any custom socket implementations you define should also provide meaningful implementations for the getOption() and setOption() methods. Your implementation may support options other than those defined here. Only custom socket implementations need to use this interface. All other code can use methods defined by Socket, ServerSocket, DatagramSocket, and MulticastSocket to set specific socket options for those socket types.
Implementations: DatagramSocketImpl, SocketImpl
This class is a java.security.Permission that governs all networking operations performed with sockets. Like all permissions, a SocketPermission consists of a name, or target, and a list of actions that may be performed on that target. The target of a SocketPermission is the host and, optionally, the port or ports for which permission is being granted or requested. The target consists of a hostname optionally followed by a colon and a port specification. The host may be a DNS domain name, a numerical IP address, or the string "localhost". If you specify a host domain name, you may use * as a wildcard as the leftmost portion of the hostname. The port specification, if present, must be a single port number or a range of port numbers in the form n1-n2. If n1 is omitted, it is taken to be 0, and if n2 is omitted, it is taken to be 65535. If no port is specified, the socket permission applies to all ports of the specified host. Here are some legal SocketPermission targets: java.sun.com:80 *.sun.com:1024-2000 *:1024- localhost:-1023 In addition to a target, each SocketPermission must have a comma-separated list of actions, which specify the operations that may be performed on the specified host(s) and port(s). The available actions are "connect", "accept", "listen", and "resolve". "connect" represents permission to connect to the specified target. "accept" indicates permission to accept connections from the specified target. "listen" represents permission to listen on the specified ports for connection requests. This action is only valid when used for ports on "localhost". Finally, the "resolve" action indicates permission to use the DNS name service to resolve domain names into IP addresses. This action is required for and implied by all other actions. System administrators configuring security policies must be familiar with this class and understand the risks of granting the various permissions it represents. System programmers writing new low-level networking libraries or connecting to native code that performs networking may need to use this class. Application programmers, however, should never need to use it directly.
Hierarchy: Object-->java.security.Permission(java.security.Guard,Serializable)-->SocketPermission(Serializable)
Signals that the name of a specified host could not be resolved.
Hierarchy: Object-->Throwable(Serializable)-->Exception-->java.io.IOException-->java.net.UnknownHostException Thrown By: InetAddress.{getAllByName(), getByName(), getLocalHost()}, Socket.Socket()
Signals an attempt to use an unsupported service of a network connection.
Hierarchy: Object-->Throwable(Serializable)-->Exception-->java.io.IOException-->UnknownServiceException
This class represents a uniform resource locator and allows the data referred to by the URL to be downloaded. A URL can be specified as a single string or with separate protocol, host, port, and file specifications. Relative URLs can also be specified with a String and the URL object to which it is relative. getFile(), getHost(), getPort(), getProtocol(), and getRef() return the various portions of the URL specified by a URL object. sameFile() determines whether a URL object refers to the same file as this one. The data or object referred to by a URL can be downloaded from the Internet in three ways: with a URLConnection created with openConnection(), with an InputStream created by openStream(), or with getContent(), which returns the URL contents directly if an appropriate ContentHandler can be found.
Hierarchy: Object-->URL(Serializable) Passed To: Too many methods to list. Returned By: Too many methods to list. Type Of: URLConnection.url
This ClassLoader provides a useful way to load untrusted Java code from a search path of arbitrary URLs, where each URL represents a directory or JAR file to search. Use the inherited loadClass() method to load a named class with a URLClassLoader. Classes loaded by a URLClassLoader have whatever permissions are granted to their java.security.CodeSource by the system java.security.Policy, plus they have one additional permission that allows the class loader to read any resource files associated with the class. If the class is loaded from a local file: URL that represents a directory, the class is given permission to read all files and directories below that directory. If the class is loaded from a local file: URL that represents a JAR file, the class is given permission to read that JAR file. If the class is loaded from a URL that represents a resource on another host, that class is given permission to connect to and accept network connections from that host. Note, however, that loaded classes are not granted this additional permission if the code that created the URLClassLoader in the first place would not have had that permission. You can obtain a URLClassLoader by calling one of the URLClassLoader() constructors or one of the static newInstance() methods. If you call newInstance(), the loadClass() method of the returned URLClassLoader performs an additional check to ensure that the caller has permission to access the specified package.
Hierarchy: Object-->ClassLoader-->java.security.SecureClassLoader-->URLClassLoader Returned By: URLClassLoader.newInstance()
This abstract class defines a network connection to an object specified by a URL. URL.openConnection() returns a URLConnection instance. You should use a URLConnection object when you want more control over the downloading of data than is available through the simpler URL methods. connect() actually makes the network connection. Other methods that depend on being connected call this method. getContent() returns the data referred to by the URL, parsed into an appropriate type of Object. If the URL protocol supports read and write operations, getInputStream() and getOutputStream() return input and output streams to the object referred to by the URL, respectively. getContentLength(), getContentType(), getContentEncoding(), getExpiration(), getDate(), and getLastModified() return the appropriate information about the object referred to by the URL, if that information can be determined (e.g., from HTTP header fields). getHeaderField() returns an HTTP header field specified by name or by number. getHeaderFieldInt() and getHeaderFieldDate() return the value of a named header field parsed as an integer or a date. There are a number of options you can specify to control how the URLConnection behaves. These options are set with the various set() methods and may be queried with corresponding get() methods. The options must be set before the connect() method is called. setDoInput() and setDoOutput() allow you to specify whether you are using the URLConnection for input and/or output (input-only by default). setAllowUserInteraction() specifies whether user interaction (such as typing a password) is allowed during the data transfer (false by default). setDefaultAllowUserInteraction() is a class method that allows you to change the default value for user interaction. setUseCaches() allows you to specify whether a cached version of the URL can be used. You can set this to false to force a URL to be reloaded. setDefaultUseCaches() sets the default value for setUseCaches(). setIfModifiedSince() allows you to specify that a URL should not be fetched unless it has been modified since a specified time (if it is possible to determine its modification date).
Subclasses: HttpURLConnection, JarURLConnection Passed To: ContentHandler.getContent() Returned By: URL.openConnection(), URLStreamHandler.openConnection() Type Of: JarURLConnection.jarFileURLConnection
This class defines a static decode() method that reverses the encoding performed by URLEncoder.encode(). It decodes 8-bit text with the MIME type "x-www-form-urlencoded", which is a standard encoding used by web browsers to submit form contents to CGI scripts and other server-side programs.
This class defines a single static method that converts a string to its URL-encoded form. That is, spaces are converted to +, and nonalphanumeric characters other than underscore are output as two hexadecimal digits following a percent sign. Note that this technique works only for 8-bit characters. This method canonicalizes a URL specification so that it uses only characters from an extremely portable subset of ASCII that can be correctly handled by computers around the world.
This abstract class defines the openConnection() method that creates a URLConnection for a given URL. A separate subclass of this class may be defined for various URL protocol types. A URLStreamHandler is created by a URLStreamHandlerFactory. Normal applications never need to use or subclass this class.
Passed To: URL.URL() Returned By: URLStreamHandlerFactory.createURLStreamHandler()
This interface defines a method that creates a URLStreamHandler object for a specified protocol. Normal applications never need to use or implement this interface.
Passed To: URL.setURLStreamHandlerFactory(), URLClassLoader.URLClassLoader() Copyright © 2001 O'Reilly & Associates. All rights reserved. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Visit relatives
问题描述 :
When Wiskey return home, many relatives he need to visit, and he will buy some gifts before he visit his relatives. There is a map which has N places; Wiskey’s house is labeled 0. He has T tasks which from u to v, it mean Wiskey could go to v when he bought a gift at u before.
Wiskey always start at 0, and must end with 0.
Tell him how many minimum total places he went when he finished all tasks.
Wiskey always start at 0, and must end with 0.
Tell him how many minimum total places he went when he finished all tasks.
输入:
First line will contain one integer mean how many cases will follow by; the number of cases wills less than 20.
In each case will contain three integers N means the number of places, M roads and T tasks. (1 <= N <= 20, 0 <= M <= 100, 0 <= T <= 5).
First, M roads will be follow; the road is bi-connected.
Second, T tasks will be follow; you are remember the u must went earlier than v, then what makes the task will be finished.
In each case will contain three integers N means the number of places, M roads and T tasks. (1 <= N <= 20, 0 <= M <= 100, 0 <= T <= 5).
First, M roads will be follow; the road is bi-connected.
Second, T tasks will be follow; you are remember the u must went earlier than v, then what makes the task will be finished.
输出:
First line will contain one integer mean how many cases will follow by; the number of cases wills less than 20.
In each case will contain three integers N means the number of places, M roads and T tasks. (1 <= N <= 20, 0 <= M <= 100, 0 <= T <= 5).
First, M roads will be follow; the road is bi-connected.
Second, T tasks will be follow; you are remember the u must went earlier than v, then what makes the task will be finished.
In each case will contain three integers N means the number of places, M roads and T tasks. (1 <= N <= 20, 0 <= M <= 100, 0 <= T <= 5).
First, M roads will be follow; the road is bi-connected.
Second, T tasks will be follow; you are remember the u must went earlier than v, then what makes the task will be finished.
样例输入:
1 7 11 5 0 1 0 2 1 2 1 4 0 3 3 4 4 6 2 6 6 5 3 5 4 5 1 2 1 3 2 0 1 4 5 3
样例输出:
7HintOne way is 0-1-2-0-1-4-5-3-0, the length is 8, and it finished all tasks. The way is 0-1-2-1-4-5-3-0 which is minimum length.
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有纹毛选的吗
居然是机试，还和13年重复。题目不难
赞一个！权限已更新:）
如果两个序列的最后字符不匹配（即X [M-1]！= Y [N-1]）
L（X [0 .. M-1]，Y [0 .. N-1]）= MAX（L（X [0 .. M-2]，Y [0 .. N-1]），L（X [0 .. M-1]，Y [0 .. N-1]）
这里写错了吧。
这个问题别太纠结了，不同的编译器结果不一
#pragma pack(2) 这个用法太坑爹
感觉这里的评分标准没啥作用阿，反而显得显得赘余，还不如直接去掉好了。
很好的思路，可以借鉴
正有此意，欢迎更多的建议~
这个是代码高亮功能，那就再换一个颜色
第二个方法挺不错。NewHead代表新的头节点，通过递归找到最后一个节点之后，就把这个节点赋给NewHead，然后一直返回返回，中途这个值是没有变化的，一边返回一边把相应的指针方向颠倒，最后结束时返回新的头节点到主函数。
这是什么鬼，怎么多头文件
额楼主能否在发布代码的同时对解题思路做个讲解呢？这样大家在学习的时候就方便多了。
程序输出是对的，呈三角型。原程序是按C++写的，已经改成了C的


[gecode-users] [ANN] gecode/prolog (yap)
Christian Schulte
cschulte at kth.se
Wed Aug 10 10:50:02 CEST 2011
Hi Denys,
I added this to the interface and news section, linking to the gmane
article. Do you intend to have a webpage to link to?
Best
Christian
--
Christian Schulte, www.ict.kth.se/~cschulte/
-----Original Message-----
From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On Behalf
Of Denys Duchier
Sent: Tuesday, August 09, 2011 6:35 PM
To: users at gecode.org
Subject: [gecode-users] [ANN] gecode/prolog (yap)
I am pleased to announce the availability of simplified gecode bindings for
yap prolog. Yap is a portable high-performance Prolog system. The gecode
bindings have been integrated into its development repository and are built
if gecode is locally installed. The development branch of Yap can be
obtained as follows:
git clone git://yap.git.sourceforge.net/gitroot/yap/yap-6.3
cd yap-6.3
git submodule init
git submodule update
to illustrate how these bindings can be used, here is SEND+MORE=MONEY:
More information about the users
mailing list


Intro --- Linnia - The Linnia protocol facilitates data sharing and permissioning - Linnia is a new way to collabore on data without intermediaries. - Linnia enables other people to add data related to any another user by using that user public key. - Also provenance of the data, by enabling other health authorities or certified actors to contribute to users profile --- Tech Matrix ID Storage Roles Metadata Computation Transmission uPort limited Independent integration Certificate Authority Plain text Metadata Simple HTH HD-Wallets over uPort Transparent multi-storage Fully Decentralized Roles. Reputation. IPLD TrueBit, Plasma Selective packet disclosure --- Storage - Current Status: Resource centralization - P2P solutions are proposed - Torrent - Web3.0: IPFS, Swarm, StorJ, MaidSafe, Sia - Local Storage - Self sovereign data --- Ethereum as a state singleton Gav Wood: “Ethereum is a collection of non-localized singleton programmable data structures”. (DevCon1, 2015) --- Linnia as the user resource instance - uPort creates a single instance of a user identity - Linked data - --- Metadata - Discoverability - Plain data - - Studied technologies: Enclaves, ---


Overview
This web resource is intended to be hidden. It can be used as follows:
-
This page can receive URL data parameters (listed below) to open a record of the target entity instead of opening the record that was originally clicked from some source page like a dashboard or queue.
- For VCCM, specific scenarios use a combination of USD Window Navigation Rules, Events, and Action Calls, along with code on this page, to open the VeteranAlerts page for the veteran whose request or interaction record was clicked on a dashboard or similar page.
-
This page can receive URL data parameters containing CTI search parameters, and fire a Navigate event to trigger a CTI listener screen pop.
Use case #1
This page can accept a single encoded "Data" parameter in its URL, which it will decode and try to find and use the following data parameters:
-
routingType
- for use case 1, value should be 'dashboard'
- sourceEntityLogicalName
- the OData name (e.g. 'ftp_interaction' or 'Incident') indicating what kind of record was selected (i.e. double-clicked) on the source dashboard page
- this is case-sensitive
-
sourceEntityId
- the GUID of the record selected on the source dashboard page
-
sourceEntityLookupFieldName
- the OData name of the lookup field on the selected record that links the selected record to a target record
- this is case-sensitive
- example: CustomerId is the OData name of the field on an Incident record can identify the contact record for whom that incident was created.
-
targetEntityName
- the OData name of the entity whose record (identified by the value of the sourceEntityLookupFieldName on the source record) we actually want to open
- for VCCM, we currently only pass a value of 'Contact' for this parameter
-
ODataSelect
- the URI-encoded oData $select string for the query that fires on the page
- example: 'ODataSelect%3Dftp_Veteran,ftp_VeteranICN,ftp_contact_ftp_interaction_Veteran/FullName,ftp_contact_ftp_interaction_Veteran/FirstName,ftp_contact_ftp_interaction_Veteran/LastName,ftp_contact_ftp_interaction_Veteran/ftp_ManuallyCreatedFromMVIcode,ftp_contact_ftp_interaction_Veteran/ftp_SensitiveVeteran,ftp_contact_ftp_interaction_Veteran/ftp_DeceasedDate'
-
ODataExpand
- the URI-encoded oData $expand string for the query that fires on the page
- if you have any fields from linked entities in the ODataSelect parameter, that relationship must be included in the ODataExpand parameter
- example (corresponding with ODataSelect example above): ODataExpand%3Dftp_contact_ftp_interaction_Veteran
Use case #2
This page can accept a single encoded "Data" parameter in its URL, which it will decode and parse for relevant data in screen pops from the Cisco Finesse web application.
If the Cisco Finesse screenpop is truly a newly-answered phone call, this page will call 'Navigate' action on the 'CTI Helper' hosted control, which will be intercepted by a CTI-specific Window Navigation Rule.
The window navigation rule will also trigger the same action call, which starts a new USD session and navigates to the MVI Search web resource, passing SSN & DOB search parameters in that URL.
The URL parameters for this page for this use case are as follows:
-
routingType
- for use case 2, should be 'cti'
-
routedurl
- contains a twice-encoded URL string, which will in turn be used in the CTI Helper.Navigate action call.
- this twice-encoded URL should be in the format of a typical CTI url pop for USD, starting with 'http://localhost:5000/?' and continuing with a series of key value pairs such as 'SSN' and 'DOB'
- the value of this parameter is supplied using the [[url]] replacement parameter provided from the Cisco hosted control's 'PopupRouted' event
-
previousurl
- contains a twice-encoded URL string, representing the last CTI URL to be popped, before the current URL (value of 'routedurl')
- this twice-encoded URL should be in the format of a typical CTI url pop for USD, starting with 'http://localhost:5000/?' and continuing with a series of key value pairs such as 'SSN' and 'DOB'
- the value of this parameter is supplied using [[$Context.lastCiscoPopup]+], and it may be empty


--- title: Home ---
Welcome to my website.
I love coding and design.
This is a work in progress, static site built with nanoc.
Thank you for visiting


NSW Planning Minister: Population growth impossible to control
by Unconventional EconomistAfter last week attacking so-called “NIMBY baby boomers” for opposing high-rise development across Sydney, NSW Planning Minister, Rob Stokes, claims it is “a completely quixotic quest” to try and control Sydney’s growth [my emphasis]:
In the next 17 years, Sydney’s population is expected to grow by 1.5 million people, a large percentage of whom will pour into the south-west growth corridor…
Conceding that the city is spreading too far too fast, Planning Minister Rob Stokes has revealed that he wants a new relationship with councils to help manage growth and infrastructure pressures.
“We want to help shape growth,” Mr Stokes said.
“Even if it were a desirable outcome to restrict growth, and I am not sure it necessarily is, but even if that is what people wanted to do that is a completely quixotic quest.
“You can’t stop it, so the best thing you can do is work together”…
 Sydney’s current population growth has been caused almost entirely by net overseas migration (NOM):
And all of Sydney’s future 4.5 million projected population increase will come from NOM:
Therefore, Sydney’s population growth could easily be “restricted” by simply returning Australia’s NOM back to the historical average of around 70,000, from 250,000 currently:
Heck, even cutting NOM to 100,000 – still a generous intake – would greatly reduce Sydney’s future population increase.
Sure, immigration policy is set by the federal government, so in this sense it is out of the NSW State Government’s control.
But why isn’t the NSW Government lobbying hard for deep cuts to the migrant intake? As the nation’s largest state, and the centre of political power, it could force the federal government’s hand.
After all, the overwhelming majority of NSW residents strongly oppose further population growth:
They know that population growth means more over-development, crush-loaded infrastructure and services, and lower living standards.
Their views are also explicitly supported by Infrastructure Australia’s modelling, which shows projects worsening traffic congestion, longer commute times, and reduced access to jobs, schools, hospitals and green space as Sydney swells to a projected 7.4 million people by 2046 under ongoing mass immigration, regardless of whether Sydney builds up or builds out:
Current mass immigration settings also means that Sydney will turn into a high-rise battery chook city mid-century, according to Urban Taskforce projections:
Rather than attacking his own constituents, Rob Stokes should represent them and lobby the federal government to slash immigration, given it is the driver of Sydney’s projected population explosion, over-development, and falling living standards.
Unconventional Economist
Leith van Onselen is Chief Economist at the MB Fund and MB Super. Leith has previously worked at the Australian Treasury, Victorian Treasury and Goldman Sachs.
Latest posts by Unconventional Economist (see all)
- Stiglitz: It’s time to dump GDP - November 26, 2019
- Regional schools now also crush-loaded - November 26, 2019
- NSW Planning Minister: Population growth impossible to control - November 26, 2019


Former Brewers catcher Grandal signs four-year deal with White Sox
by FOX Sports WisconsinThe Milwaukee Brewers will have a new starting catcher in 2020.
Yasmani Grandal parlayed a big season with Milwaukee into a four-year, $73 million contract from the Chicago White Sox, who announced the signing of the free-agent catcher Thursday.
Grandal signed a one-year, $16 million contract with the Brewers last offseason — with a mutual option, which he declined — in the hopes of cashing in this offseason in free agency. His bet on himself paid off.
Grandal played 134 games at catcher for Milwaukee in 2019, with 124 starts, and appeared in 153 games overall. He had a slash line of .246/.380/.468 with 28 home runs, 79 runs, 77 RBI and 109 walks.
He set a record for most home runs by a Brewers catcher and was the first Milwaukee player to walk 100+ times in a season since Prince Fielder, who did it from 2009-11. Grandal and Fielder are the only Brewers to reach triple digits in bases on balls in any year.
The Brewers now must figure out their plans for catcher in 2020, which currently consist of Manny Pina, whose option was picked up but who was also demoted to a backup role in 2019, and prospect Jacob Nottingham, who had a cup of coffee in 2019 but struggled in Triple-A.


{{ projects.featured_card( cms.about.featured_project ) }}
{% endif %}
{% if cms.about.featured_article %}
{{ articles.featured_card( cms.about.featured_article ) }}
{% endif %}
{{ guideposts.callout() }}
{% endblock %}
{% block scripts_extra %}
{# Any relevant scripts for this templates functionality may be included as script tags here. #}
{# These files will be minified and included at the end of the document, after any other script tags have been included. #}
{% endblock %}


| Shortcut Slots: | Select a Shortcut Slot to fill or modify the PrgLnch Shortcut, or clear the text in order to remove it with the del key or Modify Shortcut button below. The slot can be also changed by dragging in files or links, Else leave the selection on "None" to change the resolution of the current monitor. Tapping the Del key will remove all contents of the box. |
| Change, or modify Shortcut: | Depending on the contents of Shortcut Slot above, the current Prg name and/or path associated with the PrgLnch Shortcut can be added, modified, or removed with this button. To complement this facility there is support for Drag In Files, Associations & UNC paths along with provision for DosBox. |
| Command Line Extras: | Paste in any extra parameters or arguments required for the Prg to run. Not available if the Prg is a shortcut. The Del key removes everything in the box. |
| Monitor Name: | This displays the system name of the monitor that the current Prg will run on. Blue indicates a primary monitor, orange indicates a secondary monitor, and the grey, spare monitor slots. Click the label for a tooltip on monitor info. |
| Monitor List: | Numbered list of monitors. The colour of the MonitorName above indicates its usabilty. |
| Shortcut Nav. (Dlg.) vs. Resolve Shortcut: |
This check (greyed if Prg is linked directly to an executable) refers to two settings: Shortcut Nav. (Dlg.): If checked, all links in the Make Shortcut File Open dialog are supposed to be resolved, so all launchable files (bar *.lnk files) are available in the dialog. When unchecked, navigation through links in the Make Shortcut dialog is not possible, thus it's possible for the selected Prg to be a file with a *.lnk extension. See here for further details. Resolve Shortcut: This is greyed if Prg is not a .lnk file. When unchecked, the linked executable file is then launched with the properties specified in the .lnk file (seen through the file explorer) in play. Here, the PrgLnch Shortcut command line and URL options are unavailable, and the initial working directory is set via the .lnk properties. When checked, the working directory changes, Window Min-Norm-Max ,command line and URL options are available, as the resolved target is now preferred. |
| Change Resolution on Close: | When a Test Run Prg terminates, the resolution reverts to what it was directly before the Prg is run. When any Prg in a Batch Preset is terminated, the resolution reverts what it was before the batch was run. |
| Change Resolution on Switch: | Advanced Users: If a Prg is run on the same monitor as PrgLnch at a resolution other than the Default Resolution, switching from Prg to PrgLnch and vice-versa will change the resolutions accordingly. |
| Window Minimised, Normal, or Maximised: | Provisional on certain window properties of Prg, the default value is Norm (Normal) for its saved window positions and dimensions, else the Prg can be run maximised or minimised. Disabled for *.lnk files which have their own window settings configurable through explorer. While it can be applied while the test Prg is active, the values are not saved. If Prg has more than one window, the Active Window Properties dialog shows. |
| Priority: | Default value is N (Normal). Check the box for H (High) priority or clear it for BN (Below Normal). When changed while the Prg is active, the new values are saved for the next launch of Prg. |
| Borderless: |
The Borderless check (available for typical Windows subsystems) refers to two settings: Ext. Borderless: When checked, extended borderless styles are detected in addition to the commonly used size and caption styles. Apply Borderless: The regular and optionally extended borderless styles are available for toggle only on Test Runs for Prgs which are not unresolved .lnk files. For borderless windows to match the dimensions of the target monitor, maximise them first. If Prg has more than one window, the Active Window Properties dialog shows. Note: Resizing console (or command) windows or programs driven by legacy 3D engines (based on fixed screen co-ordinates), before removing borders may not always produce the desired effects. |
| Hide PrgLnch on Run: | Hides the PrgLnch Gui after a Prg is launched. The Gui will re-appear in the case of Prg termination, or the case Prg is still running and is listed as active in a Batch Preset,- followed by other active Prgs launched in the Preset that do not have this setting checked. A hidden Prglnch can be brought back with CTRL-ALT-P. |
| Show At Startup: | If checked, the current Prg shows as selected at the next run of PrgLnch. |
| Apply LAA Flag: | Writes an Large Address Aware flag to the executable. Most Prgs have this setting already. |
| Test Run Prg: | Either runs the Prg or cancels one that is running already. A notification is generated if the Prg is already active in a Batch Preset. When Shortcut Slots is "None", the button changes the resolution for the selected monitor. If a Prg on a Test Run is active after PrgLnch closes, it will not be detected as running in PrgLnch Config when PrgLnch restarts. |
| Update Prg: | Click this to update Prg to a newer version1 at the URL Location displayed in the box underneath. A progress bar and Prg Update Status indicate the download status, and on completion of the download a prompt will appear for the Prg to be launched. If Prg is a .lnk file, the Update Prg button is unavailable. Although executable files at remote URLs are better handled by PrgLnch, compressed files require external decompression programs before use. |
| Url Name: | Type in a valid Url of where the newer version of Prg is expected to reside. The Del key deletes all contents of the edit box. In the current version, at least, URL Name is not available if Prg isn't an .exe, .com or .scr by extension. |
| Prg Update Status: | A brief informational message relating to the version and availablity of Prg at the above Url. |
| Back to Prglnch: | All values are saved and returns to the PrgLnch Batch dialog. |
Author reference: Version checking is done as described here:
UrlDownloadToFile,
https://autohotkey.com/download/1.1/version.txt, C:\AutoHotkey Latest Version.txt
UrlDownloadToFile, http://someorg.org/archive.zip, C:\SomeOrg's Archive.zip
; Example: Download text to a variable:
whr := ComObjCreate("WinHttp.WinHttpRequest.5.1")
whr.Open("GET", "https://autohotkey.com/download/1.1/version.txt", true)
whr.Send()
; Using 'true' above and the call below allows the script to remain responsive.
whr.WaitForResponse()
version := whr.ResponseText
MsgBox % version


Interactive Documents
ATLAS Detector
An interactive 3D model of the atlas detector
Dataset Histograms 1
Play with historgams from the dataset yourself
Dataset Historgams 2
Play with historgams from the dataset yourself
--Blank--
New interactive tools to be added here soon
--Blank--
New interactive tools to be added here soon
--Blank--
New interactive tools to be added here soon


06 May 2015
Cappadocia, part III - Hiking and climbing
Brace for a storm of landscape shots!
The valley
The next day, Marc and I met Michal (from Poland) over breakfast. The three of us decided to go for a casual morning hike in one of the valleys (Kiliclar vadisi). The weather was gorgeous and the three of us picked a route which followed almost none of the suggested paths.
We started out by walking past (and through) some of the deserted rock houses. Having inspected them in detail, we then walked up to one of the large ridges lining the valley:
From the ridge, we climbed down into one of the smaller valleys, and for once followed a path for a while. Next, we tried to scale one of the opposite ridges, which took us over an hour. The white rock you see in the pictures is tufa, which is soft and porous at the best of times. Often enough, the rock itself was covered by layers of sand and dust, which looked just like the rockface itself. As we found out, it was utterly unsuited for even light climbing. So many times when we though we had finally found a decent route out of the valley, we had to track back after feeling our hands slip in the layers of white dust. On the plus-side, we ran into this magnificent little dinosaur!
After several failed attempts, we finally found a way up on the rock, where we looked magnificent against the backdrop of the valley.
We crossed over on the other side of the ridge and were suddenly looking down into the main valley. The fairy chimneys visible in the second picture are the same ones, Marc, Mohamed and I saw during our first day.
On the way down into the valley the three of us almost fell into a 6-8m deep chasm. No big deal though. Also, it turned out that there was a perfectly safe crossing just a few meters to the side. We just hadn’t seen it.
As you can see, the fairy chimneys have a very characteristic shape. I will leave it to you to figure out what exactly the two gentlemen were doing here:
The castle
Having seen the valley, we headed back to town in time for lunch. Marc and I were both scheduled to leave Göreme in the evening, but that would leave us the afternoon to do some more exploring. We decided on taking a minibus up to the castle which loomed over Pidgeon Valley.
The castle itself turned out to be a bit of a let-down: From outside, it looked like a bee-hive and I was excited to see what remnamts of its occupation could be found inside. The answer: None. There was nothing there but a path up to the top. The view from up there compensated us though:
After walking back down, we decided that we wanted to see the valley we had been looking down on. That was clearly one of the best decisions of my trip so far:
One entire side of the valley was lined with rocky peaks, one giant line of them which started with the castle hill itself. All along the steep rockface was a maze of houses, windows, half-eroded stairwells and scary-looking ledges. It. Was. Awesome.
The three of us set out to explore, climbing higher and higher into the rocks. We even managed to climb into several of the empty rock-houses and have a look around inside. It is difficult to convey in writing, but the whole thing felt like a giant playground and I’m not ashamed to admit I felt like a kid. Including the confident risk affinity of somebody who has no understanding of even basic mechanics but very elastic bones…
We had a whale of a time in those ruins. Nothing was off-limits, nothing was roped off. We were free to climb everywhere.
Eventually, we found a way out of the valley. As we couldn’t find a bus back, we hitchhiked the short distance.
Back in Göreme, I said my goodbyes to Marc and Michal and got on my coach to Samsun. Yes, the one I had complained about previously, that one.
Sidenote: If you go to Turkey, try to make time for Cappadocia. Just like Pammukale, it’s a unique landscape and certainly worth seeing. Next time I go there, I will definitely do one of those balloon tours which are largely accident free, but were booked out for the days we were there. I would also bring a proper camera to take some nicer pictures.
Until next time,
Arne


All Devices ( and Details
).
| # | Device Id | Device Status | Device Type | Shelter | Sector | Country | Location | Created |
|---|---|---|---|---|---|---|---|---|
| 0 | loading ... | loading ... | loading ... | loading ... | loading ... | loading ... | loading ... | loading ... |
All Sensors. ( and Sensor Details
).
| # | Code | Description | Type | Value | Read Tech |
|---|---|---|---|---|---|
| 0 | loading ... | loading ... | loading ... | loading ... | loading ... |


Client events allow you to trigger events from the clients and remove the need for events to go through a server. Client requests must be authenticated through an authentication endpoint. There are additional restrictions on client events you should be aware of. Client events can only occur on private and presence channels. You also need to explicitly enable client events in your Pusher dashboard.
If you don't need to validate or persist any data, client events avoid the overhead of sending the data to the server before its sent on to clients.
To use this code example, take a look at the source of views/client-events.html and server.js. Additionally, view the output to the JavaScript console in your browser developer tools.
For the best demo, open up two tabs so you can see messages being sent between clients.


RT @BeesandBeansPdx: Check out the new Foodzie. Today Bees & Beans is 25% off http://foodzie.com/
11/21/2011, 9:10:44 AM
Favs: 0
Retweets: 0
link--- layout: tweet ---
RT @BeesandBeansPdx: Check out the new Foodzie. Today Bees & Beans is 25% off http://foodzie.com/
11/21/2011, 9:10:44 AM
Favs: 0
Retweets: 0
link


Woman with cancer has 'best day of her life' as dying trike ride wish granted
'I still have not come down from the high'
by Ben ReidA Nottinghamshire woman has had the "best day of her life" after she was granted her dying wish to ride a motorcycle trike.
Pat Whitehead, 76, of Ollerton, was diagnosed with terminal lung cancer earlier this month and told she had four to six months to live.
She always wanted to take a journey on a motorcycle trike, and to walk the Great Wall of China.
And on Sunday, November 24, alongside her close friend Annie Homer, 78, she was granted her bucket list wish.
As she's not able to go to China, Pat's close friend Alice Brazier, 63, of Ollerton, helped grant one of her wishes by helping to organise the trike ride with a bike convoy for free.
The three friends have known each other for years and play bingo together at the Ambleside Community Centre in Yew Tree Road, Ollerton.
Volunteers came forward to take Pat on the trike, with a motorcycle convoy leaving from Ollerton and taking her to Clumber Park near Worksop and back.
"I still have not come down from the high," Pat told Nottinghamshire Live.
"It was without a doubt the best day of my life. I only wish I did it 40 years ago. I felt no pain while I was on the trike, just joy.
"We went ever so quick it was so much fun.
"I'm extremely grateful to the people who helped organise this for me. I'll never forget it.
"Nick Farmer rode the trike. He was such a gentleman. He was checking we weren't too cold and if we were okay.
"My friend Annie loved it as well. I am so happy with it. It's what I wanted to do and now I have done it."
With the General Election approaching we want to give you all the results and reactions as they happen. Join our new WhatsApp service to receive breaking news alerts throughout the night by texting ELECTION to<PHONE_NUMBER>2. The first messages will go out December 12 after polls close.


// spaces above -> skip.
if o_name == "discrete":
continue
a_name = "discrete" if alg not in ["DDPG", "SAC"] else "vector"
_do_check(alg, config, a_name, o_name)
class TestSupportedSpacesPG(unittest.TestCase):
// Do the remaining obs spaces.
assert len(OBSERVATION_SPACES_TO_TEST) >= len(ACTION_SPACES_TO_TEST)
for i, o_name in enumerate(OBSERVATION_SPACES_TO_TEST.keys()):
if i < len(ACTION_SPACES_TO_TEST):
continue
_do_check(alg, config, "discrete", o_name)


Before Change
else:
logger.debug("Grabing new file.")
if p.name != xlsx_filename:
zf = zipfile.ZipFile(p)
excel_file = pd.ExcelFile(zf.read(xlsx_filename))
else:
excel_file = pd.ExcelFile(p)
self._file_cache[xlsx_filename] = excel_file
return excel_file
def excel_filename(self, page, **partition):
After Change
pd.ExcelFile instance with the parsed excel spreadsheet frame
xlsx_filename = self.excel_filename(page, **partition)
if xlsx_filename not in self._file_cache:
excel_file = None
try:
// eia860m exports the resources as raw xlsx files that are not
// embedded in zip archives. To support this, we will first try
// to retrieve the resource directly. If this fails, we will attempt
// to open zip archive and locate the xlsx file inside that.
// TODO(rousik): if we can make it so, it would be useful to normalize
// the eia860m and zip the xlsx files. Then we could simplify this code.
res = self.ds.get_unique_resource(
self._dataset_name, name=xlsx_filename)
excel_file = pd.ExcelFile(res)
except KeyError:
zf = self.ds.get_zipfile_resource(self._dataset_name, **partition)
excel_file = pd.ExcelFile(zf.read(xlsx_filename))
finally:
self._file_cache[xlsx_filename] = excel_file
// TODO(rousik): this _file_cache could be replaced with @cache or @memoize annotations
return self._file_cache[xlsx_filename]
def excel_filename(self, page, **partition):


Contents
Using PyClaw’s solvers: Classic and SharpClaw¶
At present, PyClaw includes two types of solvers:
- Classic: the original Clawpack algorithms, in 1/2/3D
- SharpClaw: higher-order wave propagation using WENO reconstruction and Runge-Kutta integration, in 1/2D
Solver initialization takes one argument: a Riemann solver, usually from the Riemann repository. Typically, all that is needed to select a different solver is to specify it in the problem script, e.g.
>>> from clawpack import pyclaw
>>> from clawpack import riemann
>>> solver = pyclaw.ClawSolver2D(riemann.acoustics_2D)
for the 2D acoustics equations and the Classic Clawpack solver or
>>> solver = pyclaw.SharpClawSolver2D(riemann.acoustics_2D)
for the SharpClaw solver. Most of the applications distributed with PyClaw are set up to use either solver, depending on the value of the command line option solver_type, which should be set to classic or sharpclaw.
Typically, for a given grid resolution, the SharpClaw solvers are more accurate but also more computationally expensive. For typical problems involving shocks, the Classic solvers are recommended. For problems involving high-frequency waves, turbulence, or smooth solutions, the SharpClaw solvers may give more accurate solutions at less cost. This is an active area of research and you may wish to experiment with both solvers.
Future plans include incorporation of finite-difference and discontinuous Galerkin solvers.
Key differences between the Classic and SharpClaw solvers are:
- The source term routine for the Classic solver should return the integral of the source term over a step, while the source term routine for SharpClaw should return the instantaneous value of the source term.
- The solvers have different options. For a list of options and possible values, see the documentation of the ClawSolver and SharpClawSolver classes.
SharpClaw Solvers¶
The SharpClaw solvers are a collection of solvers that contain the functionality of the Fortran code SharpClaw, developed in David Ketcheson’s thesis. The 1D SharpClaw solver contains a pure Python implementation as well as a wrapped Fortran version. The 2D solver is in progress but not available yet. The SharpClaw solvers provide an interface similar to that of the classic Clawpack solvers, but with a few different options. The superclass solvers are not meant to be used separately but are there to provide common routines for all the Clawpack solvers. Please refer to each of the inherited classes for more info about the methods and attributes they provide each class. .. The inheritance structure is:
| Example: | This is a simple example of how to instantiate and evolve a solution to a later time \(\text{t_end}\) using the 1D acoustics Riemann solver. |
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>>> from clawpack import pyclaw
>>> solver = pyclaw.SharpClawSolver1D() # Instantiate a default, 1d solver
>>> solver.evolve_to_time(solution,t_end) # Evolve the solution to t_end
pyclaw.sharpclaw¶
- class pyclaw.sharpclaw.solver.SharpClawSolver(riemann_solver=None, claw_package=None)¶
Superclass for all SharpClawND solvers.
Implements Runge-Kutta time stepping and the basic form of a semi-discrete step (the dq() function). If another method-of-lines solver is implemented in the future, it should be based on this class, which then ought to be renamed to something like “MOLSolver”.
- before_step¶
Function called before each time step is taken. The required signature for this function is:
def before_step(solver,solution)
- lim_type¶
Limiter(s) to be used. 0: No limiting. 1: TVD reconstruction. 2: WENO reconstruction. Default = 2
- weno_order¶
Order of the WENO reconstruction. From 1st to 17th order (PyWENO) Default = 5
- time_integrator¶
Time integrator to be used. Currently implemented methods:
‘Euler’ : 1st-order Forward Euler integration ‘SSP33’ : 3rd-order strong stability preserving method of Shu & Osher ‘SSP104’ : 4th-order strong stability preserving method Ketcheson ‘SSPMS32’: 2nd-order strong stability preserving 3-step linear multistep method,
using Euler for starting values- ‘SSPMS43’: 3rd-order strong stability preserving 4-step linear multistep method
- using SSPRK22 for starting values
- ‘RK’ : Arbitrary Runge-Kutta method, specified by setting solver.a
- and solver.b to the Butcher arrays of the method.
- ‘LMM’ : Arbitrary linear multistep method, specified by setting the
- coefficient arrays solver.alpha and solver.beta.
Default = 'SSP104'
- char_decomp¶
Type of WENO reconstruction. 0: conservative variables WENO reconstruction (standard). 1: Wave-slope reconstruction. 2: characteristic-wise WENO reconstruction. 3: transmission-based WENO reconstruction. Default = 0
- tfluct_solver¶
Whether a total fluctuation solver have to be used. If True the function that calculates the total fluctuation must be provided. Default = False
- aux_time_dep¶
Whether the auxiliary array is time dependent. Default = False
- kernel_language¶
Specifies whether to use wrapped Fortran routines (‘Fortran’) or pure Python (‘Python’). Default = 'Fortran'.
- num_ghost¶
Number of ghost cells. Default = 3
- fwave¶
Whether to split the flux jump (rather than the jump in Q) into waves; requires that the Riemann solver performs the splitting. Default = False
- cfl_desired¶
Desired CFL number. Default = 2.45
- cfl_max¶
Maximum CFL number. Default = 2.50
- dq_src¶
Whether a source term is present. If it is present the function that computes its contribution must be provided. Default = None
- call_before_step_each_stage¶
Whether to call the method self.before_step before each RK stage. Default = False
- dq(state)¶
Evaluate dq/dt * (delta t)
- dqdt(state)¶
Evaluate dq/dt. This routine is used for implicit time stepping.
- get_cfl_max()¶
Set maximum CFL number for current step depending on time integrator
- get_dt_new()¶
Set time-step for next step depending on time integrator
- setup(solution)¶
Allocate RK stage arrays or previous step solutions and fortran routine work arrays.
- step(solution)¶
Evolve q over one time step.
Take one step with a Runge-Kutta or multistep method as specified by solver.time_integrator.
Pyclaw Classic Clawpack Solvers¶
The pyclaw classic clawpack solvers are a collection of solvers that represent the functionality of the older versions of clawpack. It comes in two forms, a pure python version and a python wrapping of the fortran libraries. All of the solvers available provide the same basic interface and provide the same options as the old versions of clawpack. The superclass solvers are not meant to be used separately but there to provide common routines for all the Clawpack solvers. Please refer to each of the inherited classes for more info about the methods and attributes they provide each class. .. The inheritance structure is:
| Example: | This is a simple example of how to instantiate and evolve a solution to a later time \(\text{t_end}\) using the linearized 1d acoustics Riemann solver |
|---|
>>> from clawpack import pyclaw
>>> solver = pyclaw.ClawSolver1D() # Instantiate a default, 1d solver
>>> solver.limiters = pyclaw.limiters.tvd.vanleer # Use the van Leer limiter
>>> solver.dt = 0.0001 # Set the initial time step
>>> solver.max_steps = 500 # Set the maximum number of time steps
>>> solver.evolve_to_time(solution,t_end) # Evolve the solution to t_end
pyclaw.classic.solver¶
- class clawpack.pyclaw.classic.solver.ClawSolver(riemann_solver=None, claw_package=None)¶
Generic classic Clawpack solver
All Clawpack solvers inherit from this base class.
- mthlim¶
Limiter(s) to be used. Specified either as one value or a list. If one value, the specified limiter is used for all wave families. If a list, the specified values indicate which limiter to apply to each wave family. Take a look at pyclaw.limiters.tvd for an enumeration. Default = limiters.tvd.minmod
- order¶
Order of the solver, either 1 for first order (i.e., Godunov’s method) or 2 for second order (Lax-Wendroff-LeVeque). Default = 2
- source_split¶
Which source splitting method to use: 1 for first order Godunov splitting and 2 for second order Strang splitting. Default = 1
- fwave¶
Whether to split the flux jump (rather than the jump in Q) into waves; requires that the Riemann solver performs the splitting. Default = False
- step_source¶
Handle for function that evaluates the source term. The required signature for this function is:
def step_source(solver,state,dt)
- before_step¶
Function called before each time step is taken. The required signature for this function is:
def before_step(solver,solution)
- kernel_language¶
Specifies whether to use wrapped Fortran routines (‘Fortran’) or pure Python (‘Python’). Default = 'Fortran'.
- verbosity¶
The level of detail of logged messages from the Fortran solver. Default = 0.
- setup(solution)¶
Perform essential solver setup. This routine must be called before solver.step() may be called.
- step(solution)¶
Evolve solution one time step
The elements of the algorithm for taking one step are:
- The before_step() function is called
- A half step on the source term step_source() if Strang splitting is being used (source_split = 2)
- A step on the homogeneous problem \(q_t + f(q)_x = 0\) is taken
- A second half step or a full step is taken on the source term step_source() depending on whether Strang splitting was used (source_split = 2) or Godunov splitting (source_split = 1)
This routine is called from the method evolve_to_time defined in the pyclaw.solver.Solver superclass.
Input: - solution - (Solution) solution to be evolved
Output: - (bool) - True if full step succeeded, False otherwise
- step_hyperbolic(solution)¶
Take one homogeneous step on the solution.
This is a dummy routine and must be overridden.


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object --+ | Facts
This class should only attempt to populate those facts that are mostly generic to all systems. This includes platform facts, service facts (e.g. ssh keys or selinux), and distribution facts. Anything that requires extensive code or may have more than one possible implementation to establish facts for a given topic should subclass Facts.
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| Generated by Epydoc 3.0.1 on Fri Jul 29 13:11:38 2016 | http://epydoc.sourceforge.net |


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