How to use Intel fortran compiler with MKL on command line - xcode

Question

I've freshly installed the Intel® Parallel Studio XE Composer Edition for Fortran OS X* (student version). It comes with the Math Kernel Library, which is why I bought it. I'm having a hard time getting started with MKL. Here's what I've done step-by-step.
1) Installed Intel® Parallel Studio XE Composer Edition for Fortran OS X* (no problem). I can run a 'hello world' script using ifort and throw the -mkl link command on at the end with no problem (not calling any mkl commands just yet).
2) Following these instructions I set my environment variables using a script provided by intel (located in opt/intel/bin to be precise). I have the intel 64-bit architecture (according to ifort -V) so I use bash mklvars.sh intel64 mod ilp64. It runs without error (or any output).
3) I write the following code to use MKL's gemm command for fortran95. Just multiplying 2 matrices.
program test
implicit none
real, dimension(2,2) :: testA, testB, testC
testA = 1
testB = 1
testC = 0 ! I don't think I need this line, but it shouldn't matter
call gemm(testA, testB, testC)
write(*,*) testC
end program test
4) I compile with ifort test_mkl.f90 -o test -mkl. I get the following error:
Undefined symbols for architecture x86_64:
"_gemm_", referenced from:
_MAIN__ in ifortSTVOrB.o
ld: symbol(s) not found for architecture x86_64
5) I try ifort test_mkl.f90 -o test -L/opt/intel/mkl/lib -mkl and get the same result.
I notice a lot of people using MKL begin their code with USE mkl95_blas, ONLY: gemm, so I put that in above implicit none in both of the above examples and get:
test_mkl.f90(4): error #7002: Error in opening the compiled module file. Check INCLUDE paths. [MKL95_BLAS]
USE mkl95_blas, ONLY: gemm
--------^
test_mkl.f90(12): error #6406: Conflicting attributes or multiple declaration of name. [GEMM]
call gemm(testA, testB, testC )
---------^
test_mkl.f90(4): error #6580: Name in only-list does not exist. [GEMM]
USE mkl95_blas, ONLY: gemm
--------------------------^
compilation aborted for test_mkl.f90 (code 1)
Any ideas as to what the problem is or how to fix this? I have successfully run a simple script in XCODE using MKL, so it's definitely something I'm doing and not my installation.

Answer 1

The documentation tells you to use the "source" command on the provided compilervars.sh script to make all the resources available. For example:
source //bin/compilervars.sh
This will add MKL to the include and library paths so that the compiler and linker can find them. If you need more help, please ask in https://software.intel.com/en-us/forums/intel-fortran-compiler-for-linux-and-mac-os-x You can get MKL-specific help in https://software.intel.com/en-us/forums/intel-math-kernel-library

Answer 2

I think your program has some bugs, first, you have to include blas95 at the beginning of your code, then, you can't use gemm, you have to choose the specific version of gemm. For example, to do real number matrix multiplication, you have to use dgemm, here is my code(Which I called test.f90), which compiles successfully using ifort -mkl test.f90 -o test.exe
program test
use blas95
implicit none
real*8,dimension(2,2)::testA,testB,testC
integer::i,j
testA=1d0
testB=1d0
testC=1d0
call dgemm("N", "N", 2, 2, 2, 1d0, A, 2, B, 2, 0, C, 2)
print *, testC
end program test