FTBFS with GetFEM>=5.4.3

[umlaeute]

As of gmm-5.4.3, gmm::lapack_ipvt is now a typedef to std::vector, which means that we can no longer use the .get() accessor, as in

plugins/6.x/src/linear_algebra/linear_algebra.cpp

Lines 3506 to 3507 in d614ade

	#if defined(GMM_VERSION)
	pivot->vr[i] = pivot__.get(i);

the commit that introduced the change is https://git.savannah.nongnu.org/cgit/getfem.git/commit/?id=cbe1442c4bb2b4fea804d47054ab55dc0bfe238c

the fix is to simply use the [] operator.
it's slightly complicated by the fact, that there's no preprocessor define to query for this API change. (at least none that i've found; i only found GMM_VERSION, but this is a string literal, so not usable for #if...)

[umlaeute]

so my solution for the Debian package of csound-plugins was to run a test-compilation in the configure stage, and use the result to determine whether we need the .get() accessor (by setting HAVE_LAPACK_IPVT_GET=1 in the preprocessor). We then use this define rather than GMM_VERSION to call the relevant code):

the patch can be found at https://salsa.debian.org/multimedia-team/csound-plugins/-/blob/master/debian/patches/gmm544.patch
or just here:

From 91636e262e21f22e4eb78fff1f09a54c66eacb9e Mon Sep 17 00:00:00 2001
From: Debian Multimedia Maintainers <debian-multimedia@lists.debian.org>
Date: Sun, 9 Feb 2025 22:01:03 +0100
Subject: [PATCH] Allow building with gmm-5.4.4

Origin: Debian
Bug: https://github.com/csound/plugins/issues/29
Last-Update: 2025-02-09

newer versions of gmm-5.4.4 have changed the type of gmm::lapack_ipvt to
std::vector, which means that elements now have to be accessed via the []
operator, rather than via a get() accessor
Last-Update: 2025-02-09
Gbp-Pq: Name gmm544.patch
---
 linear_algebra/CMakeLists.txt     | 5 +++++
 linear_algebra/linear_algebra.cpp | 8 ++++----
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/linear_algebra/CMakeLists.txt b/linear_algebra/CMakeLists.txt
index acb9b91..6a1c9f6 100644
--- a/linear_algebra/CMakeLists.txt
+++ b/linear_algebra/CMakeLists.txt
@@ -3,10 +3,15 @@ option(BUILD_LINEAR_ALGEBRA_OPCODES "Build the linear algebra opcodes" ON)
 check_deps(BUILD_LINEAR_ALGEBRA_OPCODES USE_DOUBLE)
 find_package(GMM)
 if(BUILD_LINEAR_ALGEBRA_OPCODES AND GMM_FOUND)
+    try_compile(HAVE_LAPACK_IPVT_GET "${PROJECT_BINARY_DIR}/compile_tests"
+        ${PROJECT_SOURCE_DIR}/debian/cmake/lapack_ipvt_get.cpp)
     make_plugin(linear_algebra linear_algebra.cpp)
     target_include_directories(linear_algebra PRIVATE ${GMM_INCLUDE_DIR})
     target_include_directories(linear_algebra PRIVATE ${CSOUND_INCLUDE_DIR})
     target_compile_options(linear_algebra PRIVATE "-DGMM_VERSION")
+    if (HAVE_LAPACK_IPVT_GET)
+        target_compile_options(linear_algebra PRIVATE "-DHAVE_LAPACK_IPVT_GET=1")
+    endif()
     if (MSVC)
         target_compile_options(linear_algebra PRIVATE "/D_SCL_SECURE_NO_DEPRECATE")
     endif()
diff --git a/linear_algebra/linear_algebra.cpp b/linear_algebra/linear_algebra.cpp
index a37da7c..9524574 100644
--- a/linear_algebra/linear_algebra.cpp
+++ b/linear_algebra/linear_algebra.cpp
@@ -3503,7 +3503,7 @@ public:
     gmm::copy(rhs->mr, lhs->mr);
     *isize = gmm::lu_factor(lhs->mr, pivot__);
     for (size_t i = 0; i < pivot_size; ++i) {
-#if defined(GMM_VERSION)
+#if HAVE_LAPACK_IPVT_GET
       pivot->vr[i] = pivot__.get(i);
 #else
       pivot->vr[i] = pivot__[i];
@@ -3540,7 +3540,7 @@ public:
     gmm::copy(rhs->mr, lhs->mr);
     *ksize = gmm::lu_factor(lhs->mr, pivot__);
     for (size_t i = 0; i < pivot_size; ++i) {
-#if defined(GMM_VERSION)
+#if HAVE_LAPACK_IPVT_GET
       pivot->vr[i] = pivot__.get(i);
 #else
       pivot->vr[i] = pivot__[i];
@@ -3574,7 +3574,7 @@ public:
     gmm::copy(rhs->mc, lhs->mc);
     *isize = gmm::lu_factor(lhs->mc, pivot__);
     for (size_t i = 0; i < pivot_size; ++i) {
-#if defined(GMM_VERSION)
+#if HAVE_LAPACK_IPVT_GET
       pivot->vr[i] = pivot__.get(i);
 #else
       pivot->vr[i] = pivot__[i];
@@ -3611,7 +3611,7 @@ public:
     gmm::copy(rhs->mc, lhs->mc);
     *ksize = gmm::lu_factor(lhs->mc, pivot__);
     for (size_t i = 0; i < pivot_size; ++i) {
-#if defined(GMM_VERSION)
+#if HAVE_LAPACK_IPVT_GET
       pivot->vr[i] = pivot__.get(i);
 #else
       pivot->vr[i] = pivot__[i];
-- 
2.47.2

this all depends on a c++ file that can be test-compiled:

#include <gmm/gmm.h>
int main() {
  size_t pivot_size = 10;
#if defined(GMM_VERSION)
  gmm::lapack_ipvt pivot;
#else
  std::vector<size_t> pivot;  
#endif
  pivot.resize(pivot_size);
  for (size_t i = 0; i < pivot_size; ++i) {
    int x = (int)pivot.get(i);
  }
  return 0;
}

i don't know where to put this file (for the debian package, i have just put it into a debian/cmake/lapack_ipvt_get.cpp file, but of course this won't work outside of the Debian packaging context)

there are probably better ways to do this with cmake, but i'm not really fluent here...