Cannot find libiomp5 & libpthread in MKL library

Question

Hi,

I am trying to use the MKL platform to run itensor. But I cannot find the two libraries libiomp5 & libpthread as stated in the option.mk file by

BLAS_LAPACK_LIBFLAGS=-L/opt/intel/mkl/lib/intel64 -lmkl_intel_lp64 -lmkl_intel_thread -lmkl_rt -lmkl_core -liomp5 -lpthread

What I can see in the MKL library is

mkl/lib/intel64 $ ls
libmkl_ao_worker.so             libmkl_blacs_openmpi_lp64.so  libmkl_gf_ilp64.a       libmkl_lapack95_ilp64.a    libmkl_tbb_thread.so
libmkl_avx2.so                  libmkl_blacs_sgimpt_ilp64.a   libmkl_gf_ilp64.so      libmkl_lapack95_lp64.a     libmkl_vml_avx2.so
libmkl_avx512_mic.so            libmkl_blacs_sgimpt_ilp64.so  libmkl_gf_lp64.a        libmkl_mc3.so              libmkl_vml_avx512_mic.so
libmkl_avx512.so                libmkl_blacs_sgimpt_lp64.a    libmkl_gf_lp64.so       libmkl_mc.so               libmkl_vml_avx512.so
libmkl_avx.so                   libmkl_blacs_sgimpt_lp64.so   libmkl_gnu_thread.a     libmkl_rt.so               libmkl_vml_avx.so
libmkl_blacs_intelmpi_ilp64.a   libmkl_blas95_ilp64.a         libmkl_gnu_thread.so    libmkl_scalapack_ilp64.a   libmkl_vml_cmpt.so
libmkl_blacs_intelmpi_ilp64.so  libmkl_blas95_lp64.a          libmkl_intel_ilp64.a    libmkl_scalapack_ilp64.so  libmkl_vml_def.so
libmkl_blacs_intelmpi_lp64.a    libmkl_cdft_core.a            libmkl_intel_ilp64.so   libmkl_scalapack_lp64.a    libmkl_vml_mc2.so
libmkl_blacs_intelmpi_lp64.so   libmkl_cdft_core.so           libmkl_intel_lp64.a     libmkl_scalapack_lp64.so   libmkl_vml_mc3.so
libmkl_blacs_openmpi_ilp64.a    libmkl_core.a                 libmkl_intel_lp64.so    libmkl_sequential.a        libmkl_vml_mc.so
libmkl_blacs_openmpi_ilp64.so   libmkl_core.so                libmkl_intel_thread.a   libmkl_sequential.so       locale
libmkl_blacs_openmpi_lp64.a     libmkl_def.so                 libmkl_intel_thread.so  libmkl_tbb_thread.a

Answer 1

Hi, so the exact flags you have to use varies with different installations of MKL and different versions unfortunately. On our cluster at my office, I have to include also some headers associated with the Intel compiler to get MKL to work properly (though I don't believe this is necessary in general).

As you can see in your mkl/lib/intel64 folder, there are no libiomp5.so and libpthread.so files so that's the immediate reason why you're getting the error. As to where these files actually are on your system, that sort of depends.

A very useful thing to do can be to use the Intel "Link Line Advisor" website which asks you some questions about your system then recommends linker flags:

https://software.intel.com/en-us/articles/intel-mkl-link-line-advisor

Hope that helps -

Miles