Dear all,
I have a small nonsymmetric linear system that is represented by a matrix in csr format (file fort.106). The task is to solve the system. To this end, I applied three different approaches. At first, I transformed the three csr-vectors to a dense matrix with the help of mkl_ddnscsr. Using getrf/getrs (methbutton=6) solves the system and produces reasonable results. Using the sparsity of the system, I applied intel dss (methbutton=7). However, the results obtained with this method differ from the results of getrf/getrs far beyond machine precision. Going one step further to intel pardiso (methbutton=8), produces:
forrtl: severe (174): SIGSEGV, segmentation fault occurred
Things, I have tried to avoid the problems:
-https://software.intel.com/en-us/articles/determining-root-cause-of-sigs...
-checked the sparse matrix with sparse matrix checker routines (no error)
In principle, I would have said that my matrix is the problem. However, then I would guess that getrf/getrs doesn't work either. However, since it does work, I guess the solvers are somehow the issue.
You can find my code attached (2Modes.f90). The vectors representing the matrix can be found in fort.106. The program automatically reads the vector, so you can just compile and run it. Compiling works fine with ifort -o 2Modes.out 2Modes.f90 ${MKLROOT}/lib/intel64/libmkl_blas95_ilp64.a ${MKLROOT}/lib/intel64/libmkl_lapack95_ilp64.a -Wl,--start-group ${MKLROOT}/lib/intel64/libmkl_intel_ilp64.a ${MKLROOT}/lib/intel64/libmkl_intel_thread.a ${MKLROOT}/lib/intel64/libmkl_core.a -Wl,--end-group -liomp5 -lpthread -lm -ldl -i8 -I${MKLROOT}/include/intel64/ilp64 -I${MKLROOT}/include .
The methods can be switched with the methbutton in line 41. I tried to keep the code as simple as possible. In principle, I have extracted the code from the examples which intel provides. It would be nice, if someone could take a look at this. Thank you in advance.
Best,
Horst K.
