From 4237fa888f0f537f113825557a6f0c38c2efeaff Mon Sep 17 00:00:00 2001
From: Anthony Scemama <scemama@irsamc.ups-tlse.fr>
Date: Fri, 7 Jul 2023 19:05:46 +0200
Subject: [PATCH] Get total memory

---
 src/ao_two_e_ints/cholesky.irp.f | 15 +++++++++----
 src/utils/memory.irp.f           | 36 +++++++++++++++++++++++++++++++-
 2 files changed, 46 insertions(+), 5 deletions(-)

diff --git a/src/ao_two_e_ints/cholesky.irp.f b/src/ao_two_e_ints/cholesky.irp.f
index d0fa735d..4702c850 100644
--- a/src/ao_two_e_ints/cholesky.irp.f
+++ b/src/ao_two_e_ints/cholesky.irp.f
@@ -141,7 +141,7 @@ BEGIN_PROVIDER [ integer, cholesky_ao_num ]
     logical :: memory_ok
     memory_ok = .False.
 
-    s = 1.d-2
+    s = 0.1d0
 
     ! Inrease s until the arrays fit in memory
     do 
@@ -176,7 +176,7 @@ BEGIN_PROVIDER [ integer, cholesky_ao_num ]
         exit
       endif
 
-      if (nq == 0) then
+      if ((s > 1.d0).or.(nq == 0)) then
         print *,  'Not enough memory. Reduce cholesky threshold'
         stop -1
       endif
@@ -219,10 +219,15 @@ BEGIN_PROVIDER [ integer, cholesky_ao_num ]
       stop -1
     endif
 
-    Delta(:,:) = 0.d0
 
     !$OMP PARALLEL DEFAULT(SHARED) PRIVATE(m,k,p,q,j)
 
+    !$OMP DO
+    do q=1,nq
+      Delta(:,q) = 0.d0
+    enddo
+    !$OMP ENDDO NOWAIT
+
     !$OMP DO 
     do k=1,N
       do p=1,np
@@ -232,7 +237,9 @@ BEGIN_PROVIDER [ integer, cholesky_ao_num ]
         Ltmp_q(q,k) = L(Dset(q),k)
       enddo
     enddo
-    !$OMP END DO
+    !$OMP END DO NOWAIT
+
+    !$OMP BARRIER
 
     !$OMP DO  SCHEDULE(guided)
     do m=1,nq
diff --git a/src/utils/memory.irp.f b/src/utils/memory.irp.f
index 0cd2133e..7da283ec 100644
--- a/src/utils/memory.irp.f
+++ b/src/utils/memory.irp.f
@@ -4,8 +4,10 @@ BEGIN_PROVIDER [ integer, qp_max_mem ]
  ! Maximum memory in Gb
  END_DOC
  character*(128) :: env
+ integer, external :: get_total_available_memory
 
- qp_max_mem = 500
+ qp_max_mem = get_total_available_memory()
+ call write_int(6,qp_max_mem,'Total available memory (GB)')
  call getenv('QP_MAXMEM',env)
  if (trim(env) /= '') then
     call lock_io()
@@ -122,3 +124,35 @@ subroutine print_memory_usage()
     '.. >>>>> [ RES  MEM : ', rss , &
         ' GB ] [ VIRT MEM : ', mem, ' GB ] <<<<< ..'
 end
+
+integer function get_total_available_memory() result(res)
+  implicit none
+  BEGIN_DOC
+! Returns the total available memory on the current machine
+  END_DOC
+
+  character(len=128) :: line
+  integer :: status
+  integer :: iunit
+  integer*8, parameter :: KB = 1024
+  integer*8, parameter :: GiB = 1024**3
+  integer, external :: getUnitAndOpen
+
+  iunit = getUnitAndOpen('/proc/meminfo','r')
+
+  res = 512
+  do
+      read(iunit, '(A)', END=10) line
+      if (line(1:10) == "MemTotal: ") then
+        read(line(11:), *, ERR=20) res
+        res = int((res*KB) / GiB,4)
+        exit
+ 20     continue
+      end if
+  end do
+ 10 continue
+  close(iunit)
+
+end function get_total_available_memory
+
+