我正在尝试从http://acts.nersc.gov/scalapack/hands-on/etc/pddttrdrv/pddttrdrv.c.html运行一个简单的Hello World(MKL)ScaLapack示例，但我偶然发现了一个问题(我正在使用MPICH2，并且我的操作系统是Windows)。
当我运行带有MPI标志的代码时
我得到:
{ -1, -1}: On entry to
{ -1, -1}: On entry to
parameter number 1 had an illegal value
parameter number 1 had an illegal value
和
PDDTTRF, D&C alg.: only 1 block per proc我仔细检查了这些参数，并与在线引用进行了比较，以查看这些值是否正确，并且似乎没有发现问题。
代码是:
#include <mpi.h>
#define numroc_ NUMROC
#define descinit_ DESCINIT
#include <iostream>
#include <math.h>
#include <mkl_pblas.h>
#include <mkl_scalapack.h>
#include <mkl_blacs.h>
using namespace std;
extern "C" {
/* Cblacs declarations */
void Cblacs_pinfo(int*, int*);
void Cblacs_get(int, int, int*);
void Cblacs_gridinit(int*, const char*, int, int);
void Cblacs_pcoord(int, int, int*, int*);
void Cblacs_gridexit(int);
void Cblacs_barrier(int, const char*);
void Cdgerv2d(int, int, int, double*, int, int, int);
void Cdgesd2d(int, int, int, double*, int, int, int);
void Cblacs_gridmap(int*, int*, int, int, int);
void Cblacs_exit(int);
int numroc_(int*, int*, int*, int*, int*);
}
int main(int argc, char **argv)
{
int context, desca[9], descb[9], ib, info, ja, laf, lda, ldb,
lwork, mb, mype, n, nb, npcol, npe, nprow, nrhs;
double b[4], d[4], dl[4], du[4];
double *af, *work;
char trans = 'N';
/* Set array dimensions and blocking */
n = 8; /* dimension of the problem */
lda = 4; /* leading dimension of A */
ldb = 4; /* leading dimension of B */
nrhs = 1; /* number of right-hand sides */
npcol = 2; /* number of processor columns */
ja = 1; /* offset for A */
ib = ja; /* offset for B */
mb = 4; /* blocking */
nb = 4; /* blocking */
laf = 12 * npcol + 3 * nb;
af = (double *)malloc(laf*sizeof(double));
lwork = 10 * npcol + 4 * nrhs;
work = (double *)malloc(lwork*sizeof(double));
/* Start BLACS */
Cblacs_pinfo(&mype, &npe);
Cblacs_get(0, 0, &context);
Cblacs_gridinit(&context, "R", 1, npe);
if (mype == 0){
/* PE = 0 gets D(1:4), DL(1:4), DU(1:4) and B(1:4) */
d[0] = 1.8180; d[1] = 1.6602; d[2] = 1.3420; d[3] = 1.2897;
dl[0] = 0.0000; dl[1] = 0.8385; dl[2] = 0.5681; dl[3] = 0.3704;
du[0] = 0.6946; du[1] = 0.4449; du[2] = 0.5466; du[3] = 0.7027;
b[0] = 1.0; b[1] = 2.0; b[2] = 3.0; b[3] = 4.0;
}
else if (mype == 1){
/* PE = 1 gets D(5:8), DL(5:8), DU(5:8) and B(5:8) */
d[0] = 1.3412; d[1] = 1.5341; d[2] = 1.7271; d[3] = 1.3093;
dl[0] = 0.7027; dl[1] = 0.5466; dl[2] = 0.4449; dl[3] = 0.6946;
du[0] = 0.3704; du[1] = 0.5681; du[2] = 0.8385; du[3] = 0.0000;
b[0] = 5.0; b[1] = 6.0; b[2] = 7.0; b[3] = 8.0;
}
/* Array descriptor for A (D, DL and DU) */
desca[0] = 501; desca[1] = context; desca[2] = n; desca[3] = nb;
desca[4] = 0; desca[5] = lda; desca[6] = 0;
/* Array descriptor for B */
descb[0] = 502; descb[1] = context; descb[2] = n; descb[3] = nb;
descb[4] = 0; descb[5] = ldb; descb[6] = 0;
/* Factorization */
pddttrf(&n, dl, d, du, &ja, desca, af, &laf, work, &lwork, &info);
/* Solution */
//pddttrs(&trans, &n, &nrhs, dl, d, du, &ja, desca, b, &ib, descb,
// af, &laf, work, &lwork, &info);
printf("MYPE=%i: x[:] = %7.4f %7.4f %7.4f %7.4f\n",
mype, b[0], b[1], b[2], b[3]);
Cblacs_gridexit(context);
Cblacs_exit(0);
}
最佳答案
在Intel的forum中，只是一个注释(太大而无法放入注释部分)，希望它对将来有所帮助。
[yhu5@prc-mic01 scalapack]$run -np 2 ./a.out
MYPE=0: x[:] = 1.0000 2.0000 3.0000 4.0000
MYPE=1: x[:] = 5.0000 6.0000 7.0000 8.0000
它以2级运行正常。作为设计的代码。
如果以1级运行，则按预期返回错误。
[yhu5@prc-mic01 scalapack]$ mpirun -np 1 ./a.out
{ 0, 0}: On entry to
PDDTTRF, D&C alg.: only 1 block per proc parameter number 1 had an illegal value
pddttrf problem! Info -1
MYPE=0: x[:] = 1.0000 2.0000 3.0000 4.0000
乍一看，该代码似乎出错了，因为他是
Cblacs_get(0, 0, &context);。