Hello, I am attempting to use dgetrf to get an LU factorization of a square matrix as part of a large mex program. When I check the output of dgetrf, I find the IPIV contains both a 0 and a number which is size of the matrix. I checked the documentation and it says the zero should not be there.
I have been able to reproduce this error in a smaller test case:
The C script (test_case.c)
#include "mex.h"
#include <mkl.h>
#include <math.h>
#include <stdbool.h>
#include <string.h>
#include <matrix.h>
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray * prhs[]) {
int N = (int) mxGetScalar(prhs[0]);
int M = (int) mxGetScalar(prhs[1]);
double * A = (double*) malloc(sizeof(double) * N * N);
memcpy(A, mxGetPr(prhs[2]), sizeof(double) * N * N);
double * B = (double*) malloc(sizeof(double) * N * M);
memcpy(B, mxGetPr(prhs[3]),sizeof(double) * N * M);
mexPrintf("\nA:\n");
for (int i = 0; i < N; i++) {
for (int j = 0; j < N; j++) {
mexPrintf("%f ", A[j * N + i]);
}
mexPrintf("\n");
}
mexPrintf("\nB:\n");
for (int i = 0; i < N; i++) {
for (int j = 0; j < M; j++) {
mexPrintf("%f ", B[j * N + i]);
}
mexPrintf("\n");
}
lapack_int * pivots = (lapack_int*)malloc(sizeof(lapack_int)*N);
int info = LAPACKE_dgetrf(CblasColMajor,N,N,A,N,pivots); //Turn HPH into is LU decomp
if (info != 0) {
fprintf(stderr,"info = %d\n",info);
mexErrMsgTxt("ERROR:smooth_history_simple-LAPACKE_dgetrf failed");
}
mexPrintf("\nLU_A\n");
for (int i = 0; i < N; i++) {
for (int j = 0; j < N; j++) {
mexPrintf("%f ", A[i + j * N]);
}
mexPrintf("\n");
}
mexPrintf("ipiv:\n");
for (int i = 0; i < N; i++) {
mexPrintf("%d ", pivots[i]);
}
LAPACKE_dgetrs(CblasColMajor,CblasTrans,N,M,A,N,pivots,B,M);
mexPrintf("Solution:\n");
for (int i = 0; i < N ; i++) {
for (int j = 0; j < M; j++) {
mexPrintf("%f ", B[i + N * j]);
}
mexPrintf("\n");
}
}My call to the Mex compiler is
mex CC="icc" CFLAGS="-D_GNU_SOURCE -fexceptions -fPIC -fno-omit-frame-pointer -pthread -std=c99 -mkl" -v -largeArrayDims -I/opt/intel/mkl/include -L/opt/intel/mkl/lib/intel64 -lmkl_core -lmkl_intel_ilp64 -lmkl_intel_thread -lpthread -lm -liomp5 test_case.c
Then running the Mex script in matlab, I get
>> A = [0,5,5;2,9,0;6,8,8]
A =
0 5 5
2 9 0
6 8 8
>> B = [1,0,0;0,1,0;0,0,1]
B =
1 0 0
0 1 0
0 0 1
>> test_case(3,3,A,B)
test_case(3,3,A,B)
A:
0.000000 5.000000 5.000000
2.000000 9.000000 0.000000
6.000000 8.000000 8.000000
B:
1.000000 0.000000 0.000000
0.000000 1.000000 0.000000
0.000000 0.000000 1.000000
LU_A
6.000000 8.000000 8.000000
0.333333 6.333333 -2.666667
0.000000 0.789474 7.105263
ipiv:
3 0 2
------------------------------------------------------------------------
Segmentation violation detected at Mon Jul 6 14:48:38 2015
------------------------------------------------------------------------
Configuration:
Crash Decoding : Disabled
Current Visual : 0x25 (class 4, depth 24)
Default Encoding : US-ASCII
GNU C Library : 2.5 stable
MATLAB Architecture: glnxa64
MATLAB Root : /opt/MATLAB/R2013a
MATLAB Version : 8.1.0.604 (R2013a)
Operating System : Linux 2.6.18-404.el5 #1 SMP Sat Mar 7 04:14:13 EST 2015 x86_64
Processor ID : x86 Family 6 Model 45 Stepping 2, GenuineIntel
Virtual Machine : Java 1.6.0_17-b04 with Sun Microsystems Inc. Java HotSpot(TM) 64-Bit Server VM mixed mode
Window System : Hummingbird - Open Text (13850), display localhost:35.0
Fault Count: 1
Abnormal termination:
Segmentation violation
Register State (from fault):
RAX = 0000000000000001 RBX = 0000000000000066
RCX = 00015858106d7848 RDX = 0000000000000003
RSP = 00002b0b75e504c8 RBP = 0000000000000070
RSI = 0000000000000003 RDI = 0000000000000000
R8 = 00002b0b00000003 R9 = 0000000000000003
R10 = 00002b0b94f288e0 R11 = 0000000000000000
R12 = 0000000000000003 R13 = 0000000000000003
R14 = 00000000106d77e0 R15 = 0000000000000003
RIP = 00002b0b9c2f1aa3 EFL = 0000000000010206
CS = 0033 FS = 0000 GS = 0000
Stack Trace (from fault):
[ 0] 0x00002b0b9c2f1aa3 /opt/intel/composer_xe_2013.2.146/mkl/lib/intel64/libmkl_intel_ilp64.so+03218083 LAPACKE_dge_nancheck+00000035
[ 1] 0x00002b0b9c1eccdd /opt/intel/composer_xe_2013.2.146/mkl/lib/intel64/libmkl_intel_ilp64.so+02149597 LAPACKE_dgetrs+00000141
[ 2] 0x00002b0b9ab62c4e /lcl/mq/home/m1tjm01/projects/Hess/Kalman_Filter/test_case.mexa64+00007246 mexFunction+00000670
[ 3] 0x00002b0b6cdeff8a /opt/MATLAB/R2013a/bin/glnxa64/libmex.so+00110474 mexRunMexFile+00000090
[ 4] 0x00002b0b6cdec0f9 /opt/MATLAB/R2013a/bin/glnxa64/libmex.so+00094457
[ 5] 0x00002b0b6cdecf1c /opt/MATLAB/R2013a/bin/glnxa64/libmex.so+00098076
[ 6] 0x00002b0b646e36b2 /opt/MATLAB/R2013a/bin/glnxa64/libmwm_dispatcher.so+00562866 _ZN8Mfh_file11dispatch_fhEiPP11mxArray_tagiS2_+00000594
[ 7] 0x00002b0b64b33256 /opt/MATLAB/R2013a/bin/glnxa64/libmwm_interpreter.so+02245206
[ 8] 0x00002b0b64abf09d /opt/MATLAB/R2013a/bin/glnxa64/libmwm_interpreter.so+01769629
[ 9] 0x00002b0b64ae7b0e /opt/MATLAB/R2013a/bin/glnxa64/libmwm_interpreter.so+01936142
[ 10] 0x00002b0b64ae4993 /opt/MATLAB/R2013a/bin/glnxa64/libmwm_interpreter.so+01923475
[ 11] 0x00002b0b64ae5797 /opt/MATLAB/R2013a/bin/glnxa64/libmwm_interpreter.so+01927063
[ 12] 0x00002b0b64b50e50 /opt/MATLAB/R2013a/bin/glnxa64/libmwm_interpreter.so+02367056
[ 13] 0x00002b0b646e36b2 /opt/MATLAB/R2013a/bin/glnxa64/libmwm_dispatcher.so+00562866 _ZN8Mfh_file11dispatch_fhEiPP11mxArray_tagiS2_+00000594
[ 14] 0x00002b0b64b1fdcb /opt/MATLAB/R2013a/bin/glnxa64/libmwm_interpreter.so+02166219
[ 15] 0x00002b0b64add7cc /opt/MATLAB/R2013a/bin/glnxa64/libmwm_interpreter.so+01894348
[ 16] 0x00002b0b64ad9e1d /opt/MATLAB/R2013a/bin/glnxa64/libmwm_interpreter.so+01879581
[ 17] 0x00002b0b64ada255 /opt/MATLAB/R2013a/bin/glnxa64/libmwm_interpreter.so+01880661
[ 18] 0x00002b0b6cbbdfae /opt/MATLAB/R2013a/bin/glnxa64/libmwbridge.so+00139182
[ 19] 0x00002b0b6cbbe111 /opt/MATLAB/R2013a/bin/glnxa64/libmwbridge.so+00139537
[ 20] 0x00002b0b6cbbece5 /opt/MATLAB/R2013a/bin/glnxa64/libmwbridge.so+00142565 _Z8mnParserv+00000725
[ 21] 0x00002b0b644183d2 /opt/MATLAB/R2013a/bin/glnxa64/libmwmcr.so+00447442 _ZN11mcrInstance30mnParser_on_interpreter_threadEv+00000034
[ 22] 0x00002b0b643f79ac /opt/MATLAB/R2013a/bin/glnxa64/libmwmcr.so+00313772
[ 23] 0x00002b0b643f7b88 /opt/MATLAB/R2013a/bin/glnxa64/libmwmcr.so+00314248
[ 24] 0x00002b0b6f5f15c6 /opt/MATLAB/R2013a/bin/glnxa64/libmwuix.so+00480710
[ 25] 0x00002b0b6f5fedf2 /opt/MATLAB/R2013a/bin/glnxa64/libmwuix.so+00536050
[ 26] 0x00002b0b63d68862 /opt/MATLAB/R2013a/bin/glnxa64/libmwservices.so+01845346
[ 27] 0x00002b0b63d6950f /opt/MATLAB/R2013a/bin/glnxa64/libmwservices.so+01848591 _Z25svWS_ProcessPendingEventsiib+00001615
[ 28] 0x00002b0b643f85ef /opt/MATLAB/R2013a/bin/glnxa64/libmwmcr.so+00316911
[ 29] 0x00002b0b643f8f5c /opt/MATLAB/R2013a/bin/glnxa64/libmwmcr.so+00319324
[ 30] 0x00002b0b643f2592 /opt/MATLAB/R2013a/bin/glnxa64/libmwmcr.so+00292242
[ 31] 0x000000347dc0683d /lib64/libpthread.so.0+00026685
[ 32] 0x000000347d0d4fcd /lib64/libc.so.6+00872397 clone+00000109
This error was detected while a MEX-file was running. If the MEX-file
is not an official MathWorks function, please examine its source code
for errors. Please consult the External Interfaces Guide for information
on debugging MEX-files.
If this problem is reproducible, please submit a Service Request via:
http://www.mathworks.com/support/contact_us/
A technical support engineer might contact you with further information.
Thank you for your help.** This crash report has been saved to disk as /mq/home/m1tjm01/matlab_crash_dump.21353-1 **
MATLAB is exiting because of fatal errorFrom the output, it doesn't appear to be a MATLAB or Mex error. Instead, we see that IPIV produces both a 0 and a 3 where the matrix is 3x3. Does anyone know what is going on here?