标签：lap run 并行化 sizeof comm 行存储 linux系统 main ring
在并行计算中经常需要调用scalapck(并行化的lapack)函数库里面的函数进行编程，这里简单介绍在C语言如何调用scalapck中的矩阵向量乘的函数。
注意：scalapack中的函数是用fortran写的，矩阵是按列进行存储的。
scalapack的链接需要用到blas，因此确保本机上安装好了blas、gfortran
下面是一个矩阵向量乘法的例子(为了简单计算，该程序中设定进程数为4):
#include <stdio.h> #include <string.h> #include <stdlib.h> #include "mpi.h" #define AA(i,j) AA[(i)*M+(j)]
int main(int argc, char **argv) { int i, j, k; /************ MPI ***************************/ int myrank_mpi, nprocs_mpi; MPI_Init( &argc, &argv); MPI_Comm_rank(MPI_COMM_WORLD, &myrank_mpi); MPI_Comm_size(MPI_COMM_WORLD, &nprocs_mpi); /************ BLACS ***************************/ int ictxt, nprow, npcol, myrow, mycol,nb; int info,itemp; int ZERO=0,ONE=1; nprow = 2; npcol = 2; nb = 1; Cblacs_pinfo( &myrank_mpi, &nprocs_mpi ) ; Cblacs_get( -1, 0, &ictxt ); Cblacs_gridinit( &ictxt, "Row", nprow, npcol ); Cblacs_gridinfo( ictxt, &nprow, &npcol, &myrow, &mycol ); int M = 4; int descA[9],descx[9],descy[9]; int mA = numroc_( &M, &nb, &myrow, &ZERO, &nprow ); int nA = numroc_( &M, &nb, &mycol, &ZERO, &npcol ); int nx = numroc_( &M, &nb, &myrow, &ZERO, &nprow ); int my = numroc_( &M, &nb, &myrow, &ZERO, &nprow ); descinit_(descA, &M, &M, &nb, &nb, &ZERO, &ZERO, &ictxt, &mA, &info); descinit_(descx, &M, &ONE, &nb, &ONE, &ZERO, &ZERO, &ictxt, &nx, &info); descinit_(descy, &M, &ONE, &nb, &ONE, &ZERO, &ZERO, &ictxt, &my, &info); double *x = (double*) malloc(nx*sizeof(double)); double *y = (double*) calloc(my,sizeof(double)); double *A = (double*) malloc(mA*nA*sizeof(double)); int sat,sut; for(i=0;i<mA;i++) for(j=0;j<nA;j++) A[j*mA+i]=1.0; for(i=0;i<nx;i++) x[i] = 1.0; double alpha = 1.0; double beta = 0.0; pdgemv_("N", &M, &M, &alpha, A, &ONE, &ONE, descA, x, &ONE, &ONE,descx, &ONE, &beta, y, &ONE, &ONE, descy, &ONE); for(i=0;i<my;i++) printf("rank=%d ,%f \n", myrank_mpi,y[i]); MPI_Finalize(); return 0; }
编译生成可执行文件:
mpicc -o pdgemv pdgemv.c -L/opt/scalapack/scalapck-2.0.2/ -lscalapack -lblas -lgfortran
运行：
mpirun -np 4 ./pdgemv
标签：lap run 并行化 sizeof comm 行存储 linux系统 main ring
原文地址：http://www.cnblogs.com/kuangsyx/p/7406718.html
