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scotch: add oneAPI compiler flags that disable optimizations that alter mathematical results #81

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scotch: add oneAPI compiler flags that disable optimizations that alter mathematical results #81

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30e2f2d
Add oneAPI compiler flags that disable optimizations that alter mathe…
rickgrubin-noaa Aug 14, 2026
43903c7
Simplify flags var
rickgrubin-noaa Aug 14, 2026
91f3752
Merge branch 'JCSDA:spack-stack-dev' into bugfix/scotch-div-by-zero
rickgrubin-noaa Aug 17, 2026
b06784f
Set C flags to apply to all build types
rickgrubin-noaa Aug 17, 2026
dddbc11
Explicitly set build_system based on pkg version
rickgrubin-noaa Aug 17, 2026
c06517b
Further restrain build_system when %oneapi
rickgrubin-noaa Aug 17, 2026
cd2480c
Merge branch 'spack-stack-dev' into bugfix/scotch-div-by-zero
climbfuji Aug 19, 2026
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10 changes: 9 additions & 1 deletion repos/spack_repo/builtin/packages/scotch/package.py
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Original file line number Diff line number Diff line change
Expand Up @@ -44,7 +44,9 @@ class Scotch(CMakePackage, MakefilePackage):
version("6.0.0", sha256="8206127d038bda868dda5c5a7f60ef8224f2e368298fbb01bf13fa250e378dd4")
version("5.1.10b", sha256="54c9e7fafefd49d8b2017d179d4f11a655abe10365961583baaddc4eeb6a9add")

build_system(conditional("cmake", when="@7:"), "makefile", default="cmake")
build_system("cmake", conditional("makefile", when="@:6"), default="cmake")

@climbfuji climbfuji Aug 18, 2026

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If I understand correctly, this means that for versions 6 and earlier, both cmake and makefile are an option, and the default is cmake?

The original line 47 to me reads like cmake available from version 7 and makefile available for all versions, suggesting that the cmake build wasn't available for versions 6 and earlier?

If I am right (probably not ...) and our goal is to switch from makefile for version 6 to cmake for version 7, then this is sufficient?

build_system("make", when="@:6"))
build_system("cmake", when="@7:"))

The issue with that is that line 48 effectively precludes building scotch@:6 with oneapi. But maybe that's ok. After all, we weren't able to build scotch with oneapi until recently.

@AlexanderRichert-NOAA thoughts?

@rickgrubin-noaa rickgrubin-noaa Aug 18, 2026

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If I understand correctly, this means that for versions 6 and earlier, both cmake and makefile are an option, and the default is cmake?

The original line 47 to me reads like cmake available from version 7 and makefile available for all versions, suggesting that the cmake build wasn't available for versions 6 and earlier?

7: -- only cmake for build system
:6 -- cmake or makefile, default cmake

based on your comment from JCSDA/spack-stack#2075

If I am right (probably not ...) and our goal is to switch from makefile for version 6 to cmake for version 7, then this is sufficient?

build_system("make", when="@:6"))
build_system("cmake", when="@7:"))

I was trying to allow cmake or makefile for :6 but restrict to cmake for 7: -- if it's best to only build with makefile for :6, your suggestion does that. I am certainly agnostic about it.

The issue with that is that line 48 effectively precludes building scotch@:6 with oneapi. But maybe that's ok. After all, we weren't able to build scotch with oneapi until recently.

That is the point of line 48.

@climbfuji climbfuji Aug 18, 2026

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Understood. git diff can be so confusing. Thanks for the clarification.

conflicts("build_system=makefile", when="%oneapi")

variant("threads", default=True, description="use POSIX Pthreads within Scotch and PT-Scotch")
variant(
"mpi_thread",
Expand Down Expand Up @@ -183,6 +185,12 @@ def cmake_args(self):
c_flags.append("-DINTSIZE32")
args.append(self.define("CMAKE_C_FLAGS", " ".join(c_flags)))

# oneapi C and Fortran compilers aggressively optimize floating point exception checks
if self.spec.satisfies("%oneapi@2023:"):
fcflags = "-fp-model=precise -fp-speculation=safe"
args.extend(["-DCMAKE_Fortran_FLAGS=%s" % fcflags])
args.extend(["-DCMAKE_C_FLAGS=%s" % fcflags])

return args

def is_64bit(self):
Expand Down