From 04e1b3c9db019d2052c41401f54b27035065e594 Mon Sep 17 00:00:00 2001
From: Franck HOUSSEN <fghoussen@users.noreply.github.com>
Date: Sat, 13 Aug 2022 10:29:25 +0200
Subject: [PATCH] parpack: no ILP64 support.

---
 .github/workflows/jobs.yml | 2 +-
 CHANGES                    | 1 +
 CMakeLists.txt             | 8 ++------
 README.md                  | 1 +
 configure.ac               | 8 ++------
 5 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/.github/workflows/jobs.yml b/.github/workflows/jobs.yml
index 0a7a2b0..41ccaff 100644
--- a/.github/workflows/jobs.yml
+++ b/.github/workflows/jobs.yml
@@ -153,7 +153,7 @@ jobs:
       - name: Run job
         run: |
           ./bootstrap
-          ./configure --enable-mpi --enable-icb --with-blas=mkl_gf_ilp64 --with-lapack=mkl_gf_ilp64
+          ./configure --enable-icb --with-blas=mkl_gf_ilp64 --with-lapack=mkl_gf_ilp64
           make all
           make check
         env:
diff --git a/CHANGES b/CHANGES
index c5167c4..bd924f3 100644
--- a/CHANGES
+++ b/CHANGES
@@ -30,6 +30,7 @@ arpack-ng - 3.9.0
 * [BUG FIX] Make sure iseed is always initialized to values allowed by lapack ?larnv.
 * [BUG FIX] According to lapack doc of ?larnv, iseed(4) must be odd.
 * [BUG FIX] Use MPI ICB types (mpi_f08) instead of integer(kind=i_int).
+* parpack: no ILP64 support.
 
 [ Haoyang Liu ]
  * CMake: minimum required version changed to 3.0
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0d6c386..d1041a6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -406,13 +406,9 @@ if (INTERFACE64)
       message(WARNING "build script does not know how to make your Fortran compiler use 64-bit integers: set it manually via FFLAGS.")
     endif ()
 
-    # Compiling with INTERFACE64 means you need to have control on integer type.
-    # If MPI is also required, then MPI types must be consistent with ILP64:
-    # to make sure of this, we must use the ISO_C_BINDING API provided by MPI.
+    # TODO: this needs full re-write of parpack to support ILP64...
     if (MPI)
-      if (NOT HAVE_MPI_ICB)
-        message(FATAL_ERROR "ILP64 support require use of MPI library which provides ISO_C_BINDING support.")
-      endif()
+      message(FATAL_ERROR "Parallel arpack does not support ILP64.")
     endif()
 else ()
     set(INTERFACE64 0)
diff --git a/README.md b/README.md
index 045a530..5578735 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,7 @@ Important Features:
 * arpackmm: utility to test arpack with matrix market files.
   Note: to run this utility, you need the eigen library (to handle RCI).
 * ILP64 support:
+  * Sequential arpack supports ILP64, but, parallel arpack doesn't.
   * reminder: you can NOT mix ILP64 with LP64. If you compile arpack-ng with ILP64
     (resp. LP64) support, you MUST insure your BLAS/LAPACK is compliant with ILP64
     (resp. LP64).
diff --git a/configure.ac b/configure.ac
index be93960..52e0a87 100644
--- a/configure.ac
+++ b/configure.ac
@@ -190,14 +190,10 @@ AS_IF([test x"$enable_mpi" != x"no"], [
   AC_LANG_POP([Fortran])
 ])
 
-dnl Compiling with INTERFACE64 means you need to have control on integer type.
-dnl If MPI is also required, then MPI types must be consistent with ILP64:
-dnl to make sure of this, we must use the ISO_C_BINDING API provided by MPI.
+dnl TODO: this needs full re-write of parpack to support ILP64...
 if test x"$INTERFACE64" == x"1"; then
   if test x"$enable_mpi" != x"no"; then
-    if test x"$enable_mpi_icb" == x"no"; then
-      AC_MSG_ERROR([ILP64 support require use of MPI library which provides ISO_C_BINDING support])
-    fi
+    AC_MSG_ERROR([Parallel arpack does not support ILP64.])
   fi
 fi