autoreconf -i && autoconf && CXX=icpc ./configure --enable-openmp

[joveh]

I tryed to build your tool using autoreconf -i && autoconf && CXX=icpc && ./configure --enable-openmp
Ended up with some errors
tensor.cpp:(.text+0x70dd): undefined reference to qflex::_multiply_MM
tensor.cpp:(.text+0x70dd): undefined reference to qflex::_multiply_Mv
tensor.cpp:(.text+0x70dd): undefined reference to qflex::_multiply_vM
tensor.cpp:(.text+0x70dd): undefined reference to qflex::_multiply_vv

I solved the issue by getting rid of the ifndef MKL_TENSOR enclosure adn replacing
reinterpret_cast<openblas_complex_float*>(C_data)); with reinterpret_cast<s_type::value_type*>(C_data)); in _multiply_vv