how to mex free fortran 90 format with the last matlab release

Hi every on.

It seems that by default fixed format is expected even with the file extension f90 or F90.

How to change the setting /fixed which is probably within a config file. There is no more mexopts.bat file!?

I am running R2023a release using the last intel fortran compiler. No problem with fortran 77 files and their mex gateway.

I have probably missed something but it is very strange that fortran 90 95 ... were not recognized by default.

Within mathworks doc I have not found any exemple with a such fortran code (only the same f77 code like timestwo yprime since several tens of years)

Best regards

Alain

Answer 1

[dpb]

" ... but it is very strange that fortran 90 95 ... were not recognized by default."

Oh, indeed! Add your complaint to official Mathworks support about the abominable Fortran support that is some 40+ years out of date!!! :(

To fix that problem, find the .xml file for the particular compiler release you have installed. They will be under the root MATLAB install directory under /bin/win64/mexopts.

Then remove the stupid "/fixed" switch.

There will be a line like the following in the file...that's where the problem lies -- why Mathworks can't get into at least this century is beyond ken.

COMPFLAGS="/nologo /fpp /Qprec /fixed /MD /fp:source /assume:bscc $INCLUDE $COMPDEFINES"

There's also an issue with default naming -- be sure to use the lowercase 'f' in the file names so the fortran preprocessor will run to expand the macros TMW uses for type definitions (which also still are the nonStandard and archaic REAL*N form)

[Alain Barraud]

Hi

Thanks a lot I see you agree my deception!! I am administrator of my laptop however I can't modify the xml file!!

I have used wordpad to edit the requuired file.

A workaround?

best regards

alain

[dpb]

Oh, yeah. That's MS has increased security on application folders. Start with the easy way if it is only skin deep ...<MS Link to Use controlled folder access>. I forget now just what I had to do to be able to get there; there are more if that isn't enough.

I never have managed to get the Intel compiler recognized by setup; apparently I downloaded a newer version than the supported one and haven't been able to mung on a new xml file to find it...somewhere MATLAB/TMW puts the currently selected compiler setup in the user area that mex uses; if can find it, then it should be editable I think...why TMW has to make this so complicated is just infuriating....just tell us which libraries to link to, etc., etc., and let us have at it.

[Alain Barraud]

hi again

I have only found the 2 following file "intel_fortran_23_vs2019.xml" and intel_fortran_23_vs2022.xml. I first made a copy and suppress the /fixed within the 2 original ones. Within matlab I have the following information

Building with 'Intel oneAPI 2023 for Fortran with Microsoft Visual Studio 2019'.

so the first xml file is a priori the good one.

I have also modified the same file (vs2019) found within my "user" folder.

I have always the same error!!

Surprisingly the fortran 90 syntax is accepted if I use the fix format (f77)

Until I find a solution I'll consider that it is a workaround to work with "modern" fortran

I'll write to mathworks support solve this question. Many thanks for the time you have spent to answer.

Having McAfee the idea to change folder property does not work. However using the folder properties (windows explorer) it has been possible to set a read an write property.

Best regards

[dpb]

"I have always the same error!!"

What specific error are you getting? Have you used the -verbose flag to echo the compile step to make sure getting what think are? Did you redo the "mex -setup" with the updated xml files?

Also note that if the /fixed option is not specified, Intel still follows the naming convention on what it assumes is the format--

• Files with an extension of .f90, .F90, or .i90 are free-format source files.
• Files with an extension of .f, .for, .FOR, .ftn, .FTN, .fpp, .FPP, or .i are fixed-format files.

"Surprisingly the fortran 90 syntax is accepted if I use the fix format (f77)"

That's not surprising; Fortran syntax is not dependent upon source format; only the compiler has to know which file format to parse. There are only a few rules to create source code that is acceptable either way, but there is no restriction placed on any Fortran syntax by the use of fixedform format; that is dependent only upon the level of compliance of the particular compiler to a given Standard. I believe Intel is current to the F2018 Standard so you can use anything there in your mex code; you only have to ensure to use consistent argument calling in the gateway routine to interact with the mex libraries to get data in/out of MATLAB itself--once you have the data, then "no holds barred" in how you write your other called routines.

If you don't have it handy, <Intel Fortran Doc Home Page> is here.

[James Tursa]

FYI, I submitted a bug report, again, for TMW to remove the /fixed option. I think they may finally do it in the next release.

[dpb]

We can only hope...then getting them to support the newer OneAPI compiler instead of only the legacy compiler that is no longer being updated.

While I've not tried with mex, it should also just be changing the compiler name in the xml file to make the switch (I think, I've not completely verified switches are all the same between the two, but base program compile/link/run is transparent so unless get to the more exotic things I think it should work transparently for mex). But, the better solution would be to have two sets of xml files; one for each so could pick/choose which to use if have specific reason to prefer one over the other.

Then, of course, there's still the thing of not supporting gfortran even though it is built as frontend to gcc which is supported. The lack of Fortran community support is simply appalling.

[Alain Barraud]

Thanks to every body,

I have forgotten to run again the mex -setup Fortran!!!

Now matlab finds several fortran compilers according to the different xml files i have modified or created. I have selected the adhoc one which is for me

mex -setup:'G:\Program Files\MATLAB\R2023a\bin\win64\mexopts\intel_fortran_23_vs2019.xml' FORTRAN

Now free format is recognized!!

When a solution has been found it always seems quite natural.

Within windows 11 ( profesionnel for workstation edition)it is easy to change the required folder property from read to read/write. (with windows explorer)

I have McAfee installed so the solution proposed is inactive..<MS Link to Use controlled folder access>.

May be it would be useful to put somewhere this discussion. I am sure that other matlab users can have some difficulties with modern fortran mexfile.

Best regards

Alain

[dpb]

Great! Glad to hear you got it to work successfully...

Now matlab finds several fortran compilers according to the different xml files i have modified or created"

Did you have any luck in creating a new one that the mex -setup search logic found for a different version of the Intel compiler? I somehow haven't yet figured out the link to download/install one of the older releases (although it seems others have, I have not been successful so far); I have downloaded/installed and it runs either at command line or from Visual Studio the last 2023 release, but I have not been able to create a new xml file successfully that the -setup option finds it. I don't follow which pieces of data the search actually needs in the file and from whence those magic locations/versions, etc., are obtained to make the search succeed.

[Alain Barraud]

In my mexopt folder i have a list of xml file corresponding to the set of intel fortran compilers supported by the current matlab release. I have renamed the original file corresponding to the installed intel version and suppressed the /fixed within a xml file with the original name. Once done when mex -setup Fortran is executed I see two fortran compilers one which is restricted to the fixed format the other compatible with f90 free format. Now I can select the compiler I want to use. My conclusion is that if you install several compatible intel Fortran compiler versions you can choose among them and adding new modified xml files incresses the possible choices.

Best regards

Alain

[dpb]

Agreed, that's how the -setup option works with the xml files -- my problem is I have a newer version of the Intel compiler than that which the present version of MATLAB supports and I haven't been able to manage to create a new one that works to find that version...and I don't want to switch horses in midstream of some other work on upgrading MATLAB just now and so far I've not been able to figure out how to get to the earlier Intel compiler download.