disable CXX/CC for deal.II itself #159

tjhei · 2021-01-06T20:44:40Z

As described in the comment, it is not ideal to set CXX/CC.

koecher · 2021-01-08T10:26:51Z

Strange problem. Obviously this should resolve the issue reported in the comments.

I'm wondering if it will work for my compiler setting:
I have system installed gcc, which I don't use (old version, or version may switch with system updates).
With an environment module I set a user-specific gcc (non-standard location) and user-specific mpi with that. If now the C/CXX changes to the system gcc, my mpicxx (still given to deal.II) is compiled against a "wrong" base compiler. Maybe the build will work (since both base compilers are gcc in different version) but something strange can still happen.

I suggest to introduce (additionally) a new variable for the default parameter input / configuration file, something like "reset C / CXX compiler for deal.II" (default value: false)
and, as second security of the unset C, CXX, ...,
save the original C, CXX, FC compilers before a package run and reset them afterwards (as we do for CONFOPTS in candi.sh).

tjhei · 2021-01-10T01:44:03Z

With an environment module I set a user-specific gcc (non-standard location) and user-specific mpi with that.

I assume you are running CXX=/some/other/mpicxx ./candi.sh and that mpi wrapper uses your user-installed gcc? You are right, this doesn't work correctly.

It seems to me that one needs to set both of them correctly:

CXX=g++-9 cmake -D MPI_CXX_COMPILER=/my/custom/mpicxx ...

Would you be opposed to introducing a way to specify the c++ compiler and the c++ MPI wrapper (maybe in candi.cfg or in the env?)? For example:
If only CXX is set, assume CXX is set to an MPI wrapper (and behave as before). If CXX and MPI_CXX is set, assume that CXX is the compiler and MPI_CXX is the MPI wrapper.

tjhei · 2021-01-15T15:19:31Z

Let's wait for dealii/dealii#11478

koecher · 2021-01-20T08:52:03Z

With an environment module I set a user-specific gcc (non-standard location) and user-specific mpi with that.

I assume you are running CXX=/some/other/mpicxx ./candi.sh and that mpi wrapper uses your user-installed gcc? You are right, this doesn't work correctly.

Indeed, but I set the environment variables for the compiler and mpi-compiler with environment modules. I don’t think that can work, but with my approach given above, it shouldn’t be a problem.

It seems to me that one needs to set both of them correctly:
CXX=g++-9 cmake -D MPI_CXX_COMPILER=/my/custom/mpicxx ...
Would you be opposed to introducing a way to specify the c++ compiler and the c++ MPI wrapper (maybe in candi.cfg or in the env?)? For example:
If only CXX is set, assume CXX is set to an MPI wrapper (and behave as before). If CXX and MPI_CXX is set, assume that CXX is the compiler and MPI_CXX is the MPI wrapper.

Not really, this is so non-standard that I don’t think this will work for the future. Why not going for my approach, if something goes wrong, one can tryout to reset CXX/CC in the config file, if this also doesn’t work, one needs to find another solution.

We should wait for a potential patch for deal.II of course.

tjhei · 2021-05-31T17:06:29Z

We should wait for a potential patch for deal.II of course.

It seems like we got to a conclusion in deal.II but the subtle issue remains: If you configure deal.II using candi on Ubuntu 20.04, MPI_INCLUDE_DIRS is not set correctly. You can compile&run just fine, except that my IDE (qtcreator) is missing the include path for code completion.
I am not sure if the same holds on other OSes/setups, but I would not be surprised. This is a pretty common situation, so hiding the correct solution behind a flag is not ideal.
I will need to think about this some more...

koecher · 2021-06-01T09:20:30Z

well, for my user compiled mpi-compilers I set the environment variables:

MPI_INCLUDE
MPI_HOME
MPI_LIB
MPI_BIN

and some others.

What do you mean by MPI_INCLUDE_DIRS is not set correctly? An empty string, or, even worst, a wrong string? If it is an empty string, one can set up a warning, that you should set this environment variable correctly.

koecher · 2021-06-17T14:56:01Z

@tjhei @gfcas I'm fine with that PR, if it helps you.

ghost · 2021-06-17T15:43:20Z

@tjhei @koecher Yes, this patch makes candi working for 9.3.0 (just tested again). However, I noticed that it possibly may be not necessary to set the MPI_CC_COMPILER as I get the following message after dealii configuration:

CMake Warning:
Manually-specified variables were not used by the project:

MPI_CC_COMPILER

koecher · 2021-06-17T21:12:56Z

deal.II-toolchain/packages/dealii.package


 ################################################################################
 #Choose general configuration and components of deal.II

 CONFOPTS=" \
 -D CMAKE_BUILD_TYPE=DebugRelease \
 -D DEAL_II_WITH_MPI:BOOL=ON \
+-D MPI_CXX_COMPILER=${CXX} \
+-D MPI_CC_COMPILER=${CC} \


@gfcas This line should be removed, correct?

precisely line 22 here

that was a typo, fixed.

As described in the comment, it is not ideal to set CXX/CC.

tjhei · 2021-06-18T02:03:43Z

I will need to do some additional testing...

tjhei · 2021-06-19T18:21:38Z

To conclude:

This fixes the problem that cmake does not allow specifying MPI wrappers as CXX, source: Setting CXX/CC confuses CMake MPI detection dealii#11478 (comment)
This is not a big issue but manifests itself in incomplete configuration of MPI_INCLUDE_DIRS that confuses IDEs (compilation works fine)
We actually broke configuration in deal.II 9.3 with Avoid underlinkage with OpenMPI on Debian/Ubuntu dealii#12358
I made a work-around for the error (see above) in fix cmake underlinkage error dealii#12478 which is obviously not in 9.3

I think this is good to go.

Setting the compiler wrapper in CMake instead of in CC and CXX is recommended, but only works for recent CMake versions (one configuration I tested requires CMake 3.20 for the intel compiler). With 9.3.1 deal.II supports setting CXX=mpicxx again, so only do the above when a setting in candi.cfg is specified. Works around dealii#202 and fixes feature introduced in dealii#159

Setting the compiler wrapper in CMake instead of in CC and CXX is recommended, but only works for recent CMake versions (one configuration I tested requires CMake 3.20 for the intel compiler). With 9.3.1 deal.II supports setting CXX=mpicxx again, so only do the above when a setting in candi.cfg is specified. Works around #202 and fixes feature introduced in #159

Setting the compiler wrapper in CMake instead of in CC and CXX is recommended, but only works for recent CMake versions (one configuration I tested requires CMake 3.20 for the intel compiler). With 9.3.1 deal.II supports setting CXX=mpicxx again, so only do the above when a setting in candi.cfg is specified. Works around dealii#202 and fixes feature introduced in dealii#159

tjhei mentioned this pull request Jan 7, 2021

Setting CXX/CC confuses CMake MPI detection dealii/dealii#11478

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tjhei force-pushed the dealii_without_mpicxx branch from 1f2c1cf to 50a61e2 Compare January 9, 2021 19:09

ghost mentioned this pull request Jun 17, 2021

updates deal.II stable version to 9.3.0 and adds early deprecation #186

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koecher reviewed Jun 17, 2021

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disable CXX/CC for deal.II itself

985f649

As described in the comment, it is not ideal to set CXX/CC.

tjhei force-pushed the dealii_without_mpicxx branch from 50a61e2 to 985f649 Compare June 18, 2021 01:57

ghost mentioned this pull request Jun 18, 2021

Candi development #191

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ghost mentioned this pull request Jun 21, 2021

on the master branch always use dev deal.II version #195

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koecher merged commit c6943d0 into dealii:master Jun 21, 2021

tjhei mentioned this pull request Jun 23, 2021

configuration with Intel compilers is broken #202

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tjhei mentioned this pull request Jun 28, 2021

only set MPI_CXX_COMPILER if requested #207

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koecher mentioned this pull request Jul 9, 2021

Compiler cmake issue #245

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disable CXX/CC for deal.II itself #159

disable CXX/CC for deal.II itself #159

tjhei commented Jan 6, 2021

koecher commented Jan 8, 2021

tjhei commented Jan 10, 2021

tjhei commented Jan 15, 2021

koecher commented Jan 20, 2021

tjhei commented May 31, 2021

koecher commented Jun 1, 2021

koecher commented Jun 17, 2021

ghost commented Jun 17, 2021

koecher Jun 17, 2021

koecher Jun 17, 2021

tjhei Jun 18, 2021

tjhei commented Jun 18, 2021

tjhei commented Jun 19, 2021 •

edited

disable CXX/CC for deal.II itself #159

disable CXX/CC for deal.II itself #159

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tjhei commented Jan 6, 2021

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tjhei commented Jan 10, 2021

tjhei commented Jan 15, 2021

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tjhei commented May 31, 2021

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tjhei commented Jun 19, 2021 • edited

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