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Hi,

I have some trouble using pdhseqr from ScaLAPACK (it is supposed to compute the eigen value and Schur factorization of a matrix already in Hessenberg form). It happens for both pshseqr and pdhseqr. The same happens whether I compile with MSVC 12 or Intel 14. Here is a (as much as possible) minimal code sample. It is C++ but so far I haven't had any problem with other functions from PBLAS or ScaLAPACK.

```
#include "mpi.h"
#include <algorithm> // std::max
#include <iostream>
#include "mkl.h"
#ifdef _WIN32 /* Win32 or Win64 environment */
#define numroc_ NUMROC
#define descinit_ DESCINIT
#endif
extern "C" {
/* Cblacs declarations */
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_exit(int);
int numroc_(int*, int*, int*, int*, int*);
void descinit_(int *, int *, int *, int *, int *, int *, int *,
int *, int *, int *);
void pdhseqr_(char *job, char* compz, int* n, int* ilo, int* ihi, double* h, int* desch, double* wr, double* wi, double* z, int* descz, double* work, int* lwork, int* iwork, int* liwork, int* info);
void psgemm_(char*transa, char*transb, int*m, int*n, int*k, float*alpha, float*a, int*ia, int*ja, int*desca, float*b, int*ib, int*jb, int*descb, float*beta, float*c, int*ic, int*jc, int*descc);
```

void pdgemm_(char*transa, char*transb, int*m, int*n, int*k, double*alpha, double*a, int*ia, int*ja, int*desca, double*b, int*ib, int*jb, int*descb, double*beta, double*c, int*ic, int*jc, int*descc); void pshseqr_(char *job, char* compz, int* n, int* ilo, int* ihi, float* h, int* desch, float* wr, float* wi, float* z, int* descz, float* work, int* lwork, int* iwork, int* liwork, int* info); } inline int indxl2g(int lidx, int sblock, int nprocs, int iproc) { return nprocs*sblock*(lidx / sblock) + lidx%sblock + ((nprocs + iproc - 0) % nprocs)*sblock; } int main(int argc, char* argv[]) { // Initialize parallel stuff int ctxt, myrank, myrow, mycol, numproc; MPI::Init(); myrank = MPI::COMM_WORLD.Get_rank(); numproc = MPI::COMM_WORLD.Get_size(); char major = 'R'; // the process grid will be row-major int iZERO = 0; int iONE = 1; int iMONE = -1; double dZERO = 0.0; double dONE = 1.0; double dTWO = 2.0; float fZERO = 0.0; float fONE = 1.0; float fTWO = 2.0; Cblacs_get(0, 0, &ctxt); // get the system context Cblacs_gridinit(&ctxt, &major, numproc, 1); Cblacs_pcoord(ctxt, myrank, &myrow, &mycol); // Create a shared matrix // Size of the data on the local process int M = 10; int N = 10; int block = 10; int m = numroc_(&M, &block, &myrow, &iZERO, &numproc); int n = numroc_(&N, &block, &mycol, &iZERO, &iONE); std::cout << "m, n: " << m << ", " << n << std::endl; float* H = new float[m*n]; float* Q = new float[m*n]; // Finally fill in the BLACS array descriptor int descH[9]; int descQ[9]; int info; m = std::max(1, m); // necessary because descinit() will throw if llda is 0 descinit_(descH, &m, &n, &block, &block, &iZERO, &iZERO, &ctxt, &m, &info); descinit_(descQ, &m, &n, &block, &block, &iZERO, &iZERO, &ctxt, &m, &info); //Make H and Q upper-Hessenberg for (int j = 0; j < m; ++j) { for (int k = 0; k < n; ++k) { if (indxl2g(j, block, numproc, myrow) > indxl2g(k, block, 1, mycol) + 0) { H[j + m*k] = 0; Q[j + m*k] = 0; } else{ H[j + m*k] = 1; Q[j + m*k] = 1; } } } char op = 'N'; // Compute H <- Q*Q + H, just to check that is works psgemm_(&op, &op, &M, &N, &N, &fONE, Q, &iONE, &iONE, descQ, Q, &iONE, &iONE, descQ, &fONE, H, &iONE, &iONE, descH); // Check the output for (int j = 0; j < m; ++j) { for (int k = 0; k < n; ++k) { std::cout << H[j + m*k] << "\t"; } std::cout << std::endl; } char job = 'S'; char compz = 'I'; float * wr = new float; float * wi = new float ; float lwork = -42.0; int liwork = -42; pshseqr_(&job, &compz, &N, &iONE, &N, H, descH, wr, wi, Q, descQ, &lwork, &iMONE, &liwork, &iMONE, &info); std::cout << "lwork, liwork: " << lwork << ", " << liwork << std::endl; std::cout << "info: " << info << std::endl; int work_size = 10000; float work[10000]; int iwork[10000]; pshseqr_(&job, &compz, &N, &iONE, &N, H, descH, wr, wi, Q, descQ, work, &work_size, iwork, &work_size, &info); std::cout << "info: " << info << std::endl; Cblacs_gridexit(ctxt); Cblacs_exit(0); return 0; }

And here is the output:

D:\lib\pxhseqr_minimal\x64\Debug>mpiexec -n 1 pxhseqr_minimal.exe m, n: 10, 10 2 3 4 5 6 7 8 9 10 11 0 2 3 4 5 6 7 8 9 10 0 0 2 3 4 5 6 7 8 9 0 0 0 2 3 4 5 6 7 8 0 0 0 0 2 3 4 5 6 7 0 0 0 0 0 2 3 4 5 6 0 0 0 0 0 0 2 3 4 5 0 0 0 0 0 0 0 2 3 4 0 0 0 0 0 0 0 0 2 3 0 0 0 0 0 0 0 0 0 2 lwork, liwork: 894262, -42 info: 0 { -1, -1}: On entry to job aborted: rank: node: exit code[: error message] 0: Oz: -1073741819: process 0 exited without calling finalize

If I try to run with Visual Studio's debugger I get this when pdhseqr is called the second time:

Unhandled exception at 0x00007FF6CA2D8F1D in pxhseqr_minimal.exe: 0xC0000005: Access violation reading location 0x0000000000000007.

I don't know how MKL works, but since the error message is messed up (process coordinates are -1,-1) I think it might be based on an old source where pxerbla was called with only 2 arguments (see line 357 http://www.netlib.org/scalapack/explore-html/d3/d3a/pdhseqr_8f_source.html ).

Or am I doing something wrong?

Any help would be very welcome, I have been stuck with having to compute eigen vectors in serial for a while so I would really like to get this routine to work.

Best,

Romain

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Hi Roman,

I'm glad to notify you the issue in p?hseqr and p?gebal functions are fixed in latest release MKL 11.2 update 1, which is available from Intel Registration Center. You are welcomed to try it.

Best Regards,

Ying

Link Copied

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I think it is a problem in MKL. Here is what I did:

I copied the content of the pdhseqr.f file found on the svn rep of ScaLAPACK (https://icl.cs.utk.edu/svn/scalapack-dev/scalapack/trunk/SRC/pdhseqr.f) into a new Fortran project, I gave the routine a different name (my_pdhseqr) and compiled it as a static library.

Then I linked my program to this library, and, instead of calling pdhseqr_, I called my_pdhseqr_. It kind of works now, but there are still some issues:

sometimes the value returned as the required space for the iwork array is 0, sometimes it is a large negative number. I use the abs() of the returned value and after a few tries it hasn't crashed. Using max(0, liwork) seems to sometimes cause crashing. Also, the size lwork required for the work array and returned by the routine seems exaggeratedly large: 889416 to decompose a 6-by-6 matrix.

At least the eigen values and the Schur matrix look legit (more so than the Schur matrix from pdlahqr).

That being said, it is not very convenient to compile particular functions on the side, especially since my main code is in C++ and I created a mess trying to redefine all the bacs/pblas/... prototypes with the name that the Fortran code is looking for.

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Hi Romain F.

Sorry for the slow response. You are right,the mechanism of reporting incorrect input parameters is broken in the function.

And right, it seems there are some problem also on the workspace reported by the function, we are investigating this.

But anyway, if you allocate bigger workspace as it was reported by the first query call to the function, you will get right result.

for example,

int work_size =std::max(1,(int)lwork);

float* work =(float *)malloc(work_size*sizeof(float));

int* iwork =(int *) malloc(work_size*sizeof(int));

Then the function should be work as expected.

Best Regards,

Ying

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Hi,

Is there any news on that topic?

Best,

Romain

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Hi Romain,

Thanks for asking. I checked the issue we recorded in internal database, as I see it now,

To have some progress here we split the problem in two parts: 1) incorrect workspace sizes 2) crash on incorrect input parameter.

We will try to solve the first one for the next release, so you could at least use MKL. Hopefully then you just will not face the second problem.

I will notify you when it is available. For now, you may still need the workaround , use the bigger workspace

Best Regards,

Ying

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Hi Roman,

I heard from develop team, that the issue will be fixed in latest MKL release. You are welcomed to try it and let us know if any problem.

You should be get notify when the new release is ready or obverse the notes in forum

Thanks

Ying

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Hi Roman,

I'm glad to notify you the issue in p?hseqr and p?gebal functions are fixed in latest release MKL 11.2 update 1, which is available from Intel Registration Center. You are welcomed to try it.

Best Regards,

Ying

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That is very good news, thanks for letting me know. I will try the new version as soon as I get a chance.

Best,

Romain

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