thereby forcing the processes on the sending side to wait until the receiving side is ready in Java

Drawer Data Matrix ECC200 in Java thereby forcing the processes on the sending side to wait until the receiving side is ready
thereby forcing the processes on the sending side to wait until the receiving side is ready
Creating DataMatrix In Java
Using Barcode maker for Java Control to generate, create DataMatrix image in Java applications.
Figure 610 Example of an MPI program with an update that requires mutual exclusion A single process is dedicated to the update of this data structure
Bar Code Creation In Java
Using Barcode generation for Java Control to generate, create barcode image in Java applications.
Code View: Scroll / Show All
Barcode Decoder In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
#include <mpih> // MPI include file #include <stdioh> #define N 1000 extern void consume_results(int, double, double * ); extern double big_computation(int, int); int main(int argc, char **argv) { int Tag1 = 1; int Tag2 = 2; // message tags int num_procs; // number of processes in group int ID; // unique identifier from 0 to (num_Procs-1) double local_result, global_result[N]; int i, ID_CRIT; MPI_Status stat; // MPI status parameter // Initialize MPI and set up the SPMD program MPI_Init(&argc,&argv); MPI_Comm_rank(MPI_COMM_WORLD, &ID); MPI_Comm_size (MPI_COMM_WORLD, &num_procs); // Need at least two processes for this method to work if(num_procs < 2) MPI_Abort(MPI_COMM_WORLD,-1); // Dedicate the last process to managing update of final result ID_CRIT = num_procs-1; if (ID == ID_CRIT) { int ID_sender; // variable to hold ID of sender for(i=0;i<N;i++){ MPI_Recv(&local_result, 1, MPI_DOUBLE, MPI_ANY_SOURCE, MPI_ANY_TAG, MPI_COMM_WORLD, &stat); ID_sender = statMPI_SOURCE; consume_results(ID_sender, local_result, global_result); } } else { num_procs--; for(i=ID;i<N;i+=num_procs){ // cyclic distribution of loop iterations local_result = big_computation(ID, i); // carry out UE's work // Send local result using a synchronous Send - a send that doesn't // return until a matching receive has been posted MPI_Ssend (&local_result, 1, MPIDOUBLE, ID_CRIT, ID, MPI_COMM_WORLD); } } MPI_Finalize(); return 0; }
Encode Data Matrix 2d Barcode In C#.NET
Using Barcode creation for .NET Control to generate, create Data Matrix image in Visual Studio .NET applications.
64 COMMUNICATION
Painting Data Matrix ECC200 In .NET
Using Barcode generator for ASP.NET Control to generate, create Data Matrix 2d barcode image in ASP.NET applications.
In most parallel algorithms, UEs need to exchange information as the computation proceeds Shared memory environments provide this capability by default, and the challenge in these systems is to synchronize access to shared memory so that the results are correct regardless of how the UEs are scheduled In distributed memory systems, however, it is the other way around: Because there are few, if any, shared resources, the need for explicit synchronization to protect these resources is rare Communication, however, becomes a major focus of the programmer's effort 641 Message Passing A message is the most basic communication element A message consists of a header containing data about the message (for example, source, destination, and a tag) and a series of bits to be communicated Message passing is typically two sided, meaning that a message is explicitly sent between a pair of UEs, from a specific source to a specific destination In addition to direct message passing, there are communication events that involve multiple UEs (usually all of them) in a single communication event We call this collective communication These collective communication events often include computation as well, the classic example being a global summation where a set of values distributed about the system is summed into a single value on each node In the following sections, we will explore communication mechanisms in more detail We start with basic message passing in MPI, OpenMP, and Java Then, we consider collective communication, looking in particular at the reduction operation in MPI and OpenMP We close with a brief look at other approaches to managing communication in parallel programs
DataMatrix Generator In VS .NET
Using Barcode maker for .NET Control to generate, create ECC200 image in .NET framework applications.
MPI: message passing
Data Matrix ECC200 Printer In Visual Basic .NET
Using Barcode generation for .NET framework Control to generate, create DataMatrix image in Visual Studio .NET applications.
Message passing between a pair of UEs is the most basic of the communication operations and provides a natural starting point for our discussion A message is sent by one UE and received by another In its most basic form, the send and the receive operation are paired As an example, consider the MPI program in Fig 611 and 612 In this program, a ring of processors work together to iteratively compute the elements within a field (field in the program) To keep the problem simple, we assume the dependencies in the update operation are such that each UE only needs information from its neighbor to the left to update the field We show only the parts of the program relevant to the communication The details of the actual update operation, initialization of the field, or even the structure of the field and boundary data are omitted The program in Fig 611 and 612 declares its variables and then initializes the MPI environment This is an instance of the SPMD pattern where the logic within the parallel algorithm will be driven by the process rank ID and the number of processes in the team After initializing field, we set up the communication pattern by computing two variables, left
GTIN - 12 Creation In Java
Using Barcode creator for Java Control to generate, create UCC - 12 image in Java applications.
and right, that identify which processes are located to the left and the right In this example, the computation is straightforward and implements a ring communication pattern In more complex programs, however, these index computations can be complex, obscure, and the source of many errors The core loop of the program executes a number of steps At each step, the boundary data is collected and communicated to its neighbors by shifting around a ring, and then the local block of the field controlled by the process is updated
EAN-13 Creator In Java
Using Barcode generation for Java Control to generate, create EAN 13 image in Java applications.
Figure 611 MPI program that uses a ring of processors and a communication pattern where information is shifted to the right The functions to do the computation do not affect the communication itself so they are not shown (Continued in Fig 612)
Painting EAN / UCC - 14 In Java
Using Barcode encoder for Java Control to generate, create UCC - 12 image in Java applications.
Drawing Bar Code In Java
Using Barcode creation for Java Control to generate, create bar code image in Java applications.
Make Code11 In Java
Using Barcode maker for Java Control to generate, create Code 11 image in Java applications.
Drawing Barcode In Visual Studio .NET
Using Barcode generator for ASP.NET Control to generate, create bar code image in ASP.NET applications.
Reading UPC-A Supplement 5 In Visual Studio .NET
Using Barcode recognizer for .NET Control to read, scan read, scan image in .NET framework applications.
Bar Code Generation In .NET Framework
Using Barcode creation for ASP.NET Control to generate, create barcode image in ASP.NET applications.