From fe7a5ba5d258e3fc2ef48f150915a2d79ecfae97 Mon Sep 17 00:00:00 2001
From: "Igor S. Gerasimov" <>
Date: Mon, 16 May 2022 15:33:10 +0900
Subject: [PATCH] OpenMP and MKL initialization

---
 Makefile     |  4 ++--
 Multiwfn.f90 | 22 +++++++++++++++++-----
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/Makefile b/Makefile
index 33b2243..daaa8b3 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 SIMD = -msse3
-OPT = -O2 -qopenmp -qopenmp-link=static -threads -qopt-matmul $(SIMD) -diag-disable 8290,8291,6371,10316 -fpp -mkl -static-intel
-OPT1 = -O1 -qopenmp -qopenmp-link=static -threads $(SIMD) -diag-disable 8290,8291,6371,10316 -fpp -mkl -static-intel
+OPT = -O2 -qopenmp -qopenmp-link=static -threads -qopt-matmul $(SIMD) -diag-disable 8290,8291,6371,10316 -fpp -mkl -DINTEL_MKL -static-intel
+OPT1 = -O1 -qopenmp -qopenmp-link=static -threads $(SIMD) -diag-disable 8290,8291,6371,10316 -fpp -mkl -DINTEL_MKL -static-intel
 #Options in the next line is for debugging purpose
 #OPTDBG = -O0 -qopenmp -diag-disable 8290,8291,6371 -threads -qopenmp-link=static -debug all -g -traceback -check all -fstack-protector -fpp -mkl -static-intel
 
diff --git a/Multiwfn.f90 b/Multiwfn.f90
index b1737fc..5d77558 100644
--- a/Multiwfn.f90
+++ b/Multiwfn.f90
@@ -10,7 +10,9 @@ real*8,allocatable :: tmparr(:),tmparr2(:),tmpmat(:,:),tmpmat2(:,:),tmpmat3D(:,:
 integer,allocatable :: tmparri(:),tmparr2i(:),tmpmati(:,:),tmpmat2i(:,:)
 real*8 tmpv1(3),tmpv2(3)
 
+#if defined(__INTEL_COMPILER) || defined(__INTEL_LLVM_COMPILER)
 call kmp_set_warnings_off() !In rare case, "Cannot open message catalog "1041\libiomp5ui.dll"" may occurs, this calling avoid this problem, or user should set KMP_WARNINGS environment variable to 0
+#endif
 
 !Try to get input file name from argument, which should be the first argument
 filename=" "
@@ -40,15 +42,25 @@ call date_and_time(nowdate,nowtime)
 write(*,"(/,' ( Number of parallel threads:',i4,'  Current date: ',a,'-',a,'-',a,'  Time: ',a,':',a,':',a,' )')") &
 nthreads,nowdate(1:4),nowdate(5:6),nowdate(7:8),nowtime(1:2),nowtime(3:4),nowtime(5:6)
 
-!For Linux/MacOS version, it seems the only way to set stacksize of each thread is to define KMP_STACKSIZE environment variable
-if (isys==1) then !Set via ompstacksize in settings.ini
+!For general non-compiler spicified Windows/Linux/MacOS version, it seems the only way to set stacksize of each thread is to define OMP_STACKSIZE environment variable
+if (isys==1) then
+#if defined(__INTEL_COMPILER) || defined(__INTEL_LLVM_COMPILER)
+    ! Intel OpenMP runtime can re-set OpenMP stacksize via internal call before running any OpenMP sections.
+    !Set via ompstacksize in settings.ini
     call KMP_SET_STACKSIZE_S(ompstacksize)
-else if (isys==2) then !The size should have been defined by KMP_STACKSIZE
-    CALL getenv('KMP_STACKSIZE',c200tmp)
-    if (c200tmp==" ") write(*,"(/,a)") " Warning: You should set ""KMP_STACKSIZE"" environment variable as mentioned in Section 2.1.2 of Multiwfn manual!"
+#else
+    ! Other compilers may use Intel OpenMP runtime somehow, but I (Igor S. Gerasimov) do not know how to link it, so use the way, similar to Linux
+    CALL get_environment_variable('OMP_STACKSIZE',c200tmp)
+    if (c200tmp==" ") write(*,"(/,a)") " Warning: You should set ""OMP_STACKSIZE"" environment variable as mentioned in Section 2.1.2 of Multiwfn manual!"
+#endif
+else if (isys==2) then !The size should have been defined by OMP_STACKSIZE
+    CALL get_environment_variable('OMP_STACKSIZE',c200tmp)
+    if (c200tmp==" ") write(*,"(/,a)") " Warning: You should set ""OMP_STACKSIZE"" environment variable as mentioned in Section 2.1.2 of Multiwfn manual!"
 end if
 !write(*,"(' OpenMP stacksize for each thread: ',f10.2,' MB')") dfloat(KMP_GET_STACKSIZE_S())/1024/1024
+#if defined(INTEL_MKL)
 call mkl_set_num_threads(nthreads) !Use this to set number of cores used in MKL library (e.g. function matmul_blas)
+#endif
 
 !!-------- Load input file
 write(*,*)
-- 
2.25.1