I’m working on a scientific computation project in Fortran that uses Intel’s Math Kernel Library (MKL), managed through a Conda environment. I’m encountering an issue with the DLAMCH function from LAPACK.

Environment:

• OS: Ubuntu (latest LTS)
• Compiler: gfortran (version 14.1.0)
• MKL version: 2024.2.0 (intel_663 build)
• Conda environment

In my Fortran code, I’m trying to use the DLAMCH function like this:

abstol = dlamch('S')

However, I’m getting the following error:

Error: Function 'dlamch' at (1) has no IMPLICIT type

My module uses the following MKL-related modules:

module m_model
    use iso_fortran_env, only: int64, real64, character_storage_size, int8, int32
    use iso_c_binding
    use m_myio
    use m_myxyz
    use mkl_service
    use mkl_spblas
    use mkl_solvers_ee
    implicit none
    
    ! ... rest of the module ...
end module m_model

I’ve tried adding an explicit interface for DLAMCH:

interface
    function dlamch(cmach) bind(C, name='dlamch_')
        use, intrinsic :: iso_c_binding
        implicit none
        character(1), value :: cmach
        real(c_double) :: dlamch
    end function dlamch
end interface

But this didn’t resolve the issue.

My questions are:

1. How can I properly import or declare the dlamch function from LAPACK/MKL in this Conda-managed environment?
2. Is there a specific MKL module I should be using to access LAPACK functions like DLAMCH?
3. Are there any special considerations when using LAPACK functions from MKL in a Conda environment?