Fixes for self-installed MKL from intel oneAPI (#99)

* Fixes for self-installed MKL from intel oneAPI

* introduces Pardiso.mkl_is_available() for use in runtests.jl
* test load mkl in __init__ (like pardiso)
* some link updates, hint at LD_LIBRARY_PATH
* use mkl_is_available() everywhere
* make error msg less specific if it is not available.
* introduce MKL_LOAD_FAILED flag
* set to true in __init__ if libmkl_rt cannot be loaded
* checked by mkl_is_available(), so MKLPardisoSolver()
  cannot be instantiated if load failed

---------

Co-authored-by: Kristoffer Carlsson <kcarlsson89@gmail.com>

README.md

@@ -18,20 +18,21 @@ library.
 
 ### MKL PARDISO
 
-By default Julia, will automatically install a suitable MKL for your platform.
+By default Julia, will automatically install a suitable MKL for your platform by loading `MKL_jll.jl`.
 Note that if you use a mac you will need to pin `MKL_jll` to version 2023.
 
-If you rather use a self installed MKL follow these instructions:
+If you instead use a self installed MKL, follow these instructions:
 
-* Set the `MKLROOT` environment variable. See the [MKL getting started
-  manual](https://software.intel.com/en-us/articles/intel-mkl-103-getting-started)
+* Set the `MKLROOT` environment variable. See the [MKL set environment variables
+  manual](https://www.intel.com/content/www/us/en/docs/onemkl/developer-guide-linux/2024-0/scripts-to-set-environment-variables.html)
   for a thorough guide how to set this variable correctly, typically done by
-  executing something like `source /opt/intel/mkl/bin/mklvars.sh intel64` or
+  executing something like `source /opt/intel/oneapi/setvars.sh intel64` or
   running `"C:\Program Files (x86)\IntelSWTools\compilers_and_libraries\windows\mkl\bin\mklvars.bat" intel64`
-* Run `Pkg.build("Pardiso")`
+* Run `Pkg.build("Pardiso", verbose=true)`
 * Run `Pardiso.show_build_log()` to see the build log for additional
   information.
-* Note that the `MKLROOT` environment variable must be set whenever using the library.
+* Note that the `MKLROOT` environment variable must be set, and `LD_LIBRARY_PATH` must contain `$MKLROOT/lib`  
+  whenever using the library.
 
 ### PARDISO 6.0
 

deps/build.jl

@@ -68,10 +68,10 @@ println("\nMKL Pardiso")
 println("=============")
 function find_mklparadiso()
     if haskey(ENV, "MKLROOT")
-        println("found MKLROOT environment varaible, enabling local MKL")
+        println("found MKLROOT environment variable, enabling local MKL")
         return true
     end
-    println("did not find MKLROOT environment variable, using provided MKL")
+    println("did not find MKLROOT environment variable, using MKL_jll")
     return false
 end
 

src/Pardiso.jl

@@ -26,6 +26,10 @@ if !LOCAL_MKL_FOUND
     import MKL_jll
 end
 
+MKL_LOAD_FAILED = false
+
+mkl_is_available() = (LOCAL_MKL_FOUND || MKL_jll.is_available()) && !MKL_LOAD_FAILED 
+
 if LinearAlgebra.BLAS.vendor() === :mkl && LinearAlgebra.BlasInt == Int64
     const MklInt = Int64
     const PARDISO_FUNC = :pardiso_64
@@ -109,17 +113,19 @@ const pardiso_get_schur_f = Ref{Ptr}()
 const PARDISO_LOADED = Ref(false)
 
 function __init__()
-    if MKL_jll.is_available()
-        libmkl_rt[] = MKL_jll.libmkl_rt_path
-    elseif LOCAL_MKL_FOUND
+    global MKL_LOAD_FAILED
+    if LOCAL_MKL_FOUND
         if Sys.iswindows()
             libmkl_rt[] = "mkl_rt"
         elseif Sys.isapple()
             libmkl_rt[] = "@rpath/libmkl_rt.dylib"
         else
             libmkl_rt[] = "libmkl_rt"
         end
+    elseif MKL_jll.is_available()
+        libmkl_rt[] = MKL_jll.libmkl_rt_path
     end
+
     if !haskey(ENV, "PARDISOLICMESSAGE")
         ENV["PARDISOLICMESSAGE"] = 1
     end
@@ -128,6 +134,16 @@ function __init__()
         @warn "MKLROOT not set, MKL Pardiso solver will not be functional"
     end
 
+    if mkl_is_available() 
+        try
+            libmklpardiso = Libdl.dlopen(libmkl_rt[])
+            mklpardiso_f = Libdl.dlsym(libmklpardiso, "pardiso")
+        catch e
+            @error("MKL Pardiso did not manage to load, error thrown was: $(sprint(showerror, e))")
+            MKL_LOAD_FAILED = true
+        end
+    end
+
     # This is apparently needed for MKL to not get stuck on 1 thread when
     # libpardiso is loaded in the block below...
     if libmkl_rt[] !== ""

src/mkl_pardiso.jl

@@ -13,8 +13,8 @@ mutable struct MKLPardisoSolver <: AbstractPardisoSolver
 end
 
 function MKLPardisoSolver()
-    if !MKL_jll.is_available()
-        error("MKL is not available no this platform")
+    if !(mkl_is_available())
+        error("MKL is not available")
     end
     pt = zeros(Int, 64)
     iparm = zeros(MklInt, 64)

test/runtests.jl

@@ -1,10 +1,12 @@
 ENV["OMP_NUM_THREADS"] = 2
 
+
 using Pkg
 if Sys.isapple()
     Pkg.add(name="MKL_jll"; version = "2023")
 end
 
+
 using Test
 using Pardiso
 using Random
@@ -14,7 +16,7 @@ using LinearAlgebra
 Random.seed!(1234)
 
 available_solvers = empty([Pardiso.AbstractPardisoSolver])
-if Pardiso.MKL_jll.is_available()
+if Pardiso.mkl_is_available()
     push!(available_solvers, MKLPardisoSolver)
 else
     @warn "Not testing MKL Pardiso solver"
@@ -71,7 +73,7 @@ for solver in available_solvers
     example_hermitian_psd(solver)
 end
 
-if Pardiso.MKL_jll.is_available()
+if Pardiso.mkl_is_available()
     if Sys.CPU_THREADS >= 4
         @testset "procs" begin
             ps = MKLPardisoSolver()