Hm - matlab [64bit] uses ILP64 mkl. You can try using the same ILP64 mkl from matlab - and compare.
for eg: ./configure PETSC_ARCH=arch-test --with-blaslapack-lib=/soft/com/packages/MATLAB/R2016abin/glnxa64/mkl.so -known-64-bit-blas-indices=1 Or use openblas: ./configure --download-openblas --download-openblas-64-bit-blas-indices=1 Satish On Wed, 20 Jun 2018, Najeeb Ahmad wrote: > Thanks for your prompt response Satish. > > I was getting difference in results precision between PETSc and MATLAB and > therefore wanted to try if PetscReal precision is an issue. Just noted that > KSP is converging with Residual norm of 9.283109e-02 although I have > specified -ksp_atol 1E-10 in my command options. Here is the solver setup > code: > > ierr = KSPCreate(PETSC_COMM_WORLD,&ksp);CHKERRQ(ierr); > ierr = KSPSetOperators(ksp,A,A);CHKERRQ(ierr); > ierr = KSPSetType(ksp, KSPGMRES);CHKERRQ(ierr); > ierr = KSPGetPC(ksp,&pc);CHKERRQ(ierr); > ierr = PCSetType(pc, PCJACOBI); > ierr = KSPSetFromOptions(ksp);CHKERRQ(ierr); > ierr = KSPSetUp(ksp);CHKERRQ(ierr); > > Thanks for your assistance. > > On Wed, Jun 20, 2018 at 1:13 PM Satish Balay <[email protected]> wrote: > > > Yes - ftp.mcs.anl.gov is down - and likely to be down for many hours. > > > > Sorry for the inconvinence. > > > > Unless quad precision is needed - system blas (on most machines) should > > work. > > > > Satish > > > > > > On Wed, 20 Jun 2018, Najeeb Ahmad wrote: > > > > > Hi, > > > > > > I am trying to configure PETSc with --download-f2cblaslapack but the > > > library couldn't be downloaded. I also tried to access the URL manually > > but > > > it is not accessible. Is the download server under maintenance? The URLs > > > tried by PETSc for the download are: > > > > > > > > http://ftp.mcs.anl.gov/pub/petsc/externalpackages/f2cblaslapack-3.4.2.q3.tar.gz > > > > > > and > > > > > > > > ftp://ftp.mcs.anl.gov/pub/petsc/externalpackages/f2cblaslapack-3.4.2.q3.tar.gz > > > > > > Thanks for your assistance. > > > > > > > > > > > >
