cohomolo on Windows

[rtange]

It would be nice if cohomolo were made to work on Windows.

At the moment when I load Cohomolo 1.6.6 on GAP 4.9.2 of 04-Jul-2018 on Windows 7 and type

G:=SymmetricGroup(5);;p:=2;;
chr:=CHR(G,2,0,Z(2)*[[[1]],[[1]]]);;
FirstCohomologyDimension(chr);

I get:

'rm' is not recognized as an internal or external command,
operable program or batch file.
Error, no method found! For debugging hints type ?Recovery from NoMethodFound
Error, no 1st choice method found for `SetPrintFormattingStatus' on 2 arguments
The 1st argument is 'fail' which might point to an earlier problem
 at /proc/cygdrive/C/gap-4.9.2/lib/methsel2.g:250 called from
SetPrintFormattingStatus( stream, false ); at /proc/cygdrive/C/gap-4.9.2/pkg/cohomolo-1.6.6/gap/coho4.g:57 called from
COHOMOLO.WritePermGroup( G, deg, base, Concatenation( filename, ".inperm" )
 ); at /proc/cygdrive/C/gap-4.9.2/pkg/cohomolo-1.6.6/gap/coho4.g:600 called from
Cohomolo( chr, false, false, true, TmpName(  )
 ); at /proc/cygdrive/C/gap-4.9.2/pkg/cohomolo-1.6.6/gap/coho4.g:899 called from
<function "FirstCohomologyDimension">( <arguments> )
 called from read-eval loop at *stdin*:4

In the past it has been noted that cohomolo can work on Windows: ""cohomolo" also runs seemingly OK on Windows with Cygwin" See https://mail.gap-system.org/pipermail/forum/2004.txt

But I could not make it work with these instructions.

Rudolf Tange

[fingolfin]

@ChrisJefferson any idea if this might work now on Windows?

It complains about rm missing but that should be fine these days?

[rtange]

In GAP 4.10.1 of 23-Feb-2019 (on Windows 10 Enterprise) I still get the same error message as above. Is this only supposed to be resolved in GAP 4.12.0? And should it then be installed using Windows Subsystem for Linux?

[fingolfin]

Might also be resolved in 4.11.1 which I think already had the "new" Windows installer.

Any particular reason you don't want to update to 4.12.0?

[ChrisJefferson]

Here's 4.12.0, the standard windows release. You can also use GAP in the "Windows Subsystem for Linux". Nowadays most things work equally well in the "proper windows" and "Windows Subsystem for Linux" releases of GAP. It is probably better to use Windows Subsystem for Linux, if you are familiar with Linux, because it tends to be faster, and it is easier to do things like installing new versions of packages.

 ┌───────┐   GAP 4.12.0 of 2022-08-18
 │  GAP  │   https://www.gap-system.org
 └───────┘   Architecture: x86_64-pc-cygwin-default64-kv8
 Configuration:  gmp 6.2.1, GASMAN, readline
 Loading the library and packages ...
 Packages:   AClib 1.3.2, Alnuth 3.2.1, AtlasRep 2.1.4, AutoDoc 2022.07.10, AutPGrp 1.11, Browse 1.8.14,
             CaratInterface 2.3.4, CRISP 1.4.5, Cryst 4.1.25, CrystCat 1.1.10, CTblLib 1.3.4, FactInt 1.6.3,
             FGA 1.4.0, Forms 1.2.8, GAPDoc 1.6.6, genss 1.6.7, IO 4.7.2, IRREDSOL 1.4.3, LAGUNA 3.9.5, orb 4.8.5,
             Polenta 1.3.10, Polycyclic 2.16, PrimGrp 3.4.2, RadiRoot 2.9, recog 1.3.2, ResClasses 4.7.3,
             SmallGrp 1.5, Sophus 1.27, SpinSym 1.5.2, TomLib 1.2.9, TransGrp 3.6.3, utils 0.76
 Try '??help' for help. See also '?copyright', '?cite' and '?authors'
gap> LoadPackage("cohomolo");
─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
Loading  cohomolo 1.6.10 (Computing Cohomology groups and Schur Multipliers)
by Derek Holt (http://homepages.warwick.ac.uk/staff/D.F.Holt/).
maintained by:
   The GAP Team (support@gap-system.org).
Homepage: https://gap-packages.github.io/cohomolo
Report issues at https://github.com/gap-packages/cohomolo/issues
─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
true
gap> G:=SymmetricGroup(5);;p:=2;;
gap> chr:=CHR(G,2,0,Z(2)*[[[1]],[[1]]]);;
gap> FirstCohomologyDimension(chr);
1
gap>

[rtange]

I installed GAP 4.12.0 via the windows installer and it works now, but the commmand "FirstCohomologyDimension(chr);" took more than 10 seconds and on a unix machine it gave the output immediately. So I will probably reinstall with WSL.