GAP libsing in Sage

How to install libsing in GAP in Sage

• Install gap-4.5.5 in Sage, if needed (see 13211)

• Open a Sage shell (sage -sh)

• Issue the commands

  cd $SAGE_LOCAL/gap-newest/pkg
  hg clone ssh://hg@hg.gap-system.org/libsingular
  cd libsingular
  ./fetchsingular
  

  TODO: Can we use Singular-3.1.5 from the spkg at 13237?

• Edit makesingular: It should be

  export CFLAGS="-O0 -g $CFLAGS"
  export CXXFLAGS="-O0 -g $CXXFLAGS"
  

• Issue the commands

  export LDFLAGS="-L$SAGE_LOCAL/lib -ldl -lpthread"
  export CFLAGS="-I$SAGE_LOCAL/include"
  export CPPFLAGS="-I$SAGE_LOCAL/include"
  makesingular
  

• Edit $SAGE_LOCAL/gap-newest/src/gmpints.h, comment out the lines 54-58

  #ifndef __GNU_MP_RELEASE
   #if __GMP_MP_RELEASE < 50002
   #error Aborting compile: GAP requires GMP 5.0.2 or newer
   #endif
  #endif
  

• Issue the commands

  ./configure --with-gaproot=$SAGE_LOCAL/gap-newest
  export LDFLAGS="-L$SAGE_LOCAL/lib -ldl -lpthread -L$SAGE_LOCAL/gap-newest/pkg/libsingular/Singular-3-1-5/Singular"
  make
  

• Edit the GAP starter script (`which gap`) and add the line (say, in line 12)

  export LD_LIBRARY_PATH="$SAGE_LOCAL/gap-newest/pkg/libsingular/Singular-3-1-5/Singular:$LD_LIBRARY_PATH"
  

• Run some example, such as the one in $SAGE_LOCAL/gap-newest/pkg/libsingular/example