I'm getting the following error and i'm not sure why.
{ 1, 1}: On entry to PDPOTRF parameter number 2 had an illegal value
{ 1, 0}: On entry to PDPOTRF parameter number 2 had an illegal value
{ 0, 1}: On entry to PDPOTRF parameter number 2 had an illegal value
{ 0, 0}: On entry to PDPOTRF parameter number 2 had an illegal value
info < 0: If the i-th argument is an array and the j-entry had an illegal value, then INFO = -(i*100+j), if the i-th argument is a scalar and had an illegal value, then INFO = -i.
I Know what the error messages means but I followed the dated documentation available on the web as best as possible and tried to piece together a parallel cholesky factorization from working example codes on the web. I'm not sure where I went wrong.
Could some one explain where I went wrong in the code below? Here's an overview of what the code does, I'm testing with 4 processors and divide the 8x8 matrix into 2 x 2 processor block grid loads a matrix from file, heres an example 8 x 8 matrixfile ,
182 147 140 125 132 76 126 157
147 213 185 150 209 114 166 188
140 185 232 129 194 142 199 205
125 150 129 143 148 81 104 150
132 209 194 148 214 122 172 189
76 114 142 81 122 102 129 117
126 166 199 104 172 129 187 181
157 188 205 150 189 117 181 259
I followed examples to distribute the Matrix to 4 separate 4x4 local arrays one on each of the 4 nodes. I then run descinit_ and call the associated pdpotrf_ routine which yields the above error. I have no idea where i went wrong and tried to follow documentation as best as I could. A working example of a parallel cholesky decomposition in fortran would also greatly help
References for function calls
Run Parameters
code name - Meaning = Value
N - Global Rows = 8
M - Global Cols = 8
Nb - Local Block Rows = 2
Mb - Local Block Cols = 2
nrows - Local Rows = 4
ncols Local Cols= 4
lda - Leading dimension of local array = 4 (i've tried 2,4,8)
ord - Order of Matrix = 4 (i've also tried many different things here as well)
I Printed the above parameters on every node and they are the same
#include <mpi.h>
#include <iostream>
#include <iomanip>
#include <string>
#include <fstream>
#include <iostream>
#include <stdlib.h>
#include <sstream>
using namespace std;
/*
To compile:
mpic++ test.cpp -o test -L/home/admin/libs -lscalapack -lrefblas -ltmg -lreflapack -lgfortran -Wall -O2
To run:
mpirun -np 4 ./test matrixfile 8 8 2 2
*/
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_gridinfo(int, int*, int*, 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);
int numroc_(int*, int*, int*, int*, int*);
void pdpotrf_(char*, int*, double*,
int*, int*, int*, int*);
void descinit_( int *, int *, int *, int *, int *, int *, int *,
int *, int *, int *);
}
int main(int argc, char **argv){
/* MPI */
int mpirank,nprocs;
MPI_Init(&argc, &argv);
MPI_Comm_rank(MPI_COMM_WORLD, &mpirank);
MPI_Comm_size(MPI_COMM_WORLD, &nprocs);
double MPIelapsed;
double MPIt2;
double MPIt1;
/* Helping vars */
int iZERO = 0;
int verbose = 1;
bool mpiroot = (mpirank == 0);
if (argc < 6) {
if (mpiroot)
cerr << "Usage: matrixTest matrixfile N M Nb Mb"
<< endl
<< " N = Rows , M = Cols , Nb = Row Blocks , Mb = Col Blocks "
<< endl;
MPI_Finalize();
return 1;
}
/* Scalapack / Blacs Vars */
int N, M, Nb, Mb;
int descA[9];
int info = 0;
// int mla = 4;
int ord = 8;
double *A_glob = NULL, *A_glob2 = NULL, *A_loc = NULL;
/* Parse command line arguments */
if (mpiroot) {
/* Read command line arguments */
stringstream stream;
stream << argv[2] << " " << argv[3] << " " << argv[4] << " " << argv[5];
stream >> N >> M >> Nb >> Mb;
/* Reserve space and read matrix (with transposition!) */
A_glob = new double[N*M];
A_glob2 = new double[N*M];
string fname(argv[1]);
ifstream file(fname.c_str());
for (int r = 0; r < N; ++r) {
for (int c = 0; c < M; ++c) {
file >> *(A_glob + N*c + r);
}
}
/* Print matrix */
if(verbose == 1) {
cout << "Matrix A:\n";
for (int r = 0; r < N; ++r) {
for (int c = 0; c < M; ++c) {
cout << setw(3) << *(A_glob + N*c + r) << " ";
}
cout << "\n";
}
cout << endl;
}
}
/* Begin Cblas context */
int ctxt, myid, myrow, mycol, numproc;
//<TODO> make dynamic
int procrows = 2, proccols = 2;
Cblacs_pinfo(&myid, &numproc);
Cblacs_get(0, 0, &ctxt);
Cblacs_gridinit(&ctxt, "Row-major", procrows, proccols);
Cblacs_gridinfo( ctxt, &procrows, &proccols, &myrow, &mycol );
/* process coordinates for the process grid */
// Cblacs_pcoord(ctxt, myid, &myrow, &mycol);
/* Broadcast of the matrix dimensions */
int dimensions[4];
if (mpiroot) {
dimensions[0] = N;//Global Rows
dimensions[1] = M;//Global Cols
dimensions[2] = Nb;//Local Rows
dimensions[3] = Mb;//Local Cols
}
MPI_Bcast(dimensions, 4, MPI_INT, 0, MPI_COMM_WORLD);
MPI_Bcast(&ord, 1, MPI_INT, 0, MPI_COMM_WORLD);
N = dimensions[0];
M = dimensions[1];
Nb = dimensions[2];
Mb = dimensions[3];
int nrows = numroc_(&N, &Nb, &myrow, &iZERO, &procrows);
int ncols = numroc_(&M, &Mb, &mycol, &iZERO, &proccols);
int lda = max(1,nrows);
MPI_Bcast(&lda, 1, MPI_INT, 0, MPI_COMM_WORLD);
/* Print grid pattern */
if (myid == 0)
cout << "Processes grid pattern:" << endl;
for (int r = 0; r < procrows; ++r) {
for (int c = 0; c < proccols; ++c) {
Cblacs_barrier(ctxt, "All");
if (myrow == r && mycol == c) {
cout << myid << " " << flush;
}
}
Cblacs_barrier(ctxt, "All");
if (myid == 0)
cout << endl;
}
if(myid == 0){
cout <<"Run Parameters"<<endl;
cout <<"Global Rows = " << M <<endl;
cout <<"Global Cols = " << N <<endl;
cout <<"Local Block Rows = " << Mb <<endl;
cout <<"Local Block Cols = " << Nb <<endl;
cout << "nrows = "<<nrows<<endl;
cout << "ncols = "<<ncols<<endl;
cout << "lda = "<<lda<<endl;
cout <<"Order = "<<ord<<endl;
}
for (int id = 0; id < numproc; ++id) {
Cblacs_barrier(ctxt, "All");
}
A_loc = new double[nrows*ncols];
for (int i = 0; i < nrows*ncols; ++i) *(A_loc+i)=0.;
/* Scatter matrix */
int sendr = 0, sendc = 0, recvr = 0, recvc = 0;
for (int r = 0; r < N; r += Nb, sendr=(sendr+1)%procrows) {
sendc = 0;
int nr = Nb;
if (N-r < Nb)
nr = N-r;
for (int c = 0; c < M; c += Mb, sendc=(sendc+1)%proccols) {
int nc = Mb;
if (M-c < Mb)
nc = M-c;
if (mpiroot) {
Cdgesd2d(ctxt, nr, nc, A_glob+N*c+r, N, sendr, sendc);
}
if (myrow == sendr && mycol == sendc) {
Cdgerv2d(ctxt, nr, nc, A_loc+nrows*recvc+recvr, nrows, 0, 0);
recvc = (recvc+nc)%ncols;
}
}
if (myrow == sendr)
recvr = (recvr+nr)%nrows;
}
/* Print local matrices */
if(verbose == 1) {
for (int id = 0; id < numproc; ++id) {
if (id == myid) {
cout << "A_loc on node " << myid << endl;
for (int r = 0; r < nrows; ++r) {
for (int c = 0; c < ncols; ++c)
cout << setw(3) << *(A_loc+nrows*c+r) << " ";
cout << endl;
}
cout << endl;
}
Cblacs_barrier(ctxt, "All");
}
}
for (int id = 0; id < numproc; ++id) {
Cblacs_barrier(ctxt, "All");
}
/* DescInit */
info=0;
descinit_(descA, &N, &M, &Nb, &Mb,&iZERO,&iZERO,&ctxt, &lda, &info);
if(mpiroot){
if(verbose == 1){
if (info == 0){
cout<<"Description init sucesss!"<<endl;
}
if(info < 0){
cout <<"Error Info < 0: if INFO = -i, the i-th argument had an illegal value"<< endl
<<"Info = " << info<<endl;
}
}
// Cblacs_barrier(ctxt, "All");
}
//psgesv_(n, 1, al, 1,1,idescal, ipiv, b, 1,1,idescb, info) */
// psgesv_(&n, &one, al, &one,&one,idescal, ipiv, b, &one,&one,idescb, &info);
//pXelset http://www.netlib.org/scalapack/tools/pdelset.f
/* CHOLESKY HERE */
info = 0;
MPIt1=MPI_Wtime();
pdpotrf_("L",&ord,A_loc,&Nb,&Mb,descA,&info);
for (int id = 0; id < numproc; ++id) {
Cblacs_barrier(ctxt, "All");
}
MPIt2 = MPI_Wtime();
MPIelapsed=MPIt2-MPIt1;
if(mpiroot){
std::cout<<"Cholesky MPI Run Time" << MPIelapsed<<std::endl;
if(info == 0){
std::cout<<"SUCCESS"<<std::endl;
}
if(info < 0){
cout << "info < 0: If the i-th argument is an array and the j-entry had an illegal value, then INFO = -(i*100+j), if the i-th argument is a scalar and had an illegal value, then INFO = -i. " << endl;
cout<<"info = " << info << endl;
}
if(info > 0){
std::cout<<"matrix is not positve definte"<<std::endl;
}
}
//sanity check set global matrix to zero before it's recieved by nodes
if(mpiroot){
for (int r = 0; r < N; ++r) {
for (int c = 0; c < M; ++c) {
A_glob2[c *N + r] = 0;
}
}
}
/* Gather matrix */
sendr = 0;
for (int r = 0; r < N; r += Nb, sendr=(sendr+1)%procrows) {
sendc = 0;
// Number of rows to be sent
// Is this the last row block?
int nr = Nb;
if (N-r < Nb)
nr = N-r;
for (int c = 0; c < M; c += Mb, sendc=(sendc+1)%proccols) {
// Number of cols to be sent
// Is this the last col block?
int nc = Mb;
if (M-c < Mb)
nc = M-c;
if (myrow == sendr && mycol == sendc) {
// Send a nr-by-nc submatrix to process (sendr, sendc)
Cdgesd2d(ctxt, nr, nc, A_loc+nrows*recvc+recvr, nrows, 0, 0);
recvc = (recvc+nc)%ncols;
}
if (mpiroot) {
// Receive the same data
// The leading dimension of the local matrix is nrows!
Cdgerv2d(ctxt, nr, nc, A_glob2+N*c+r, N, sendr, sendc);
}
}
if (myrow == sendr)
recvr = (recvr+nr)%nrows;
}
/* Print test matrix */
if (mpiroot) {
if(verbose == 1){
cout << "Matrix A test:\n";
for (int r = 0; r < N; ++r) {
for (int c = 0; c < M; ++c) {
cout << setw(3) << *(A_glob2+N*c+r) << " ";
}
cout << endl;
}
}
}
/* Release resources */
delete[] A_glob;
delete[] A_glob2;
delete[] A_loc;
Cblacs_gridexit(ctxt);
MPI_Finalize();
}
Right - I solved this. Here's what you have to do (I checked the result of the modified MPI program against a Cholesky decomp of your matrix in Octave -- it works.).
I found the following LAPACK reference by IBM to be more helpful than the one in your link: http://publib.boulder.ibm.com/infocenter/clresctr/vxrx/index.jsp?topic=%2Fcom.ibm.cluster.pessl.v4r2.pssl100.doc%2Fam6gr_lpotrf.htm
PDPOTRF( UPLO, N, A, IA, JA, DESCA, INFO )
You are passing Mb and Nb as IA and JA. However, those parameters are meant to provide the starting row and column of your global matrix inside a larger matrix. They are only relevant if you have a big matrix and only want the Cholesky decomp of a submatrix. In your case, IA and JA both have to be 1!
So all you need to do is:
int IA = 1;
int JA = 1;
pdpotrf_("L",&ord,A_loc,&IA,&JA,descA,&info);
You may also want to change your hardcoded int ord = 8; so that it depends on the value read from the command line, otherwise you'll run into problems later.
Output of your program modified as described above:
Cholesky MPI Run Time0.000659943
SUCCESS
Matrix A test:
13.4907 147 140 125 132 76 126 157
10.8964 9.70923 185 150 209 114 166 188
10.3775 7.4077 8.33269 129 194 142 199 205
9.26562 5.0507 -0.548194 5.59806 148 81 104 150
9.78449 10.5451 1.72175 0.897537 1.81524 122 172 189
5.63349 5.41911 5.20784 0.765767 0.0442447 3.63139 129 117
9.33974 6.61543 6.36911 -2.22569 1.03941 2.48498 1.79738 181
11.6376 6.30249 4.50561 2.28799 -0.627688 -2.17633 7.27182 0.547228
Octave output for comparison:
octave:1> A=dlmread("matrixfile4")
A =
182 147 140 125 132 76 126 157
147 213 185 150 209 114 166 188
140 185 232 129 194 142 199 205
125 150 129 143 148 81 104 150
132 209 194 148 214 122 172 189
76 114 142 81 122 102 129 117
126 166 199 104 172 129 187 181
157 188 205 150 189 117 181 259
octave:2> C=chol(A)
C =
13.49074 10.89636 10.37749 9.26562 9.78449 5.63349 9.33974 11.63761
0.00000 9.70923 7.40770 5.05070 10.54508 5.41911 6.61543 6.30249
0.00000 0.00000 8.33269 -0.54819 1.72175 5.20784 6.36911 4.50561
0.00000 0.00000 0.00000 5.59806 0.89754 0.76577 -2.22569 2.28799
0.00000 0.00000 0.00000 0.00000 1.81524 0.04424 1.03941 -0.62769
0.00000 0.00000 0.00000 0.00000 0.00000 3.63139 2.48498 -2.17633
0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 1.79738 7.27182
0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.54723
(My earlier comment -now deleted- about matrices being wrongly copied to the nodes does not apply, the rest of your program seems fine to me.)
来源：https://stackoverflow.com/questions/14147705/cholesky-decomposition-scalapack-error