Thanks for the information. But it seems SCSCP.IO_PickleToString calls IO.IO_Pickle() according to this page
http://www.gap-system.org/Manuals/pkg/scscp/doc/chap9.html#X84F055ED860120D5 and the description of the string output is that it is in ""pickled" format as OpenMath strings”. I don’t need OM output, it’s just important that it is a compact string output that can be used to reconstruct the object if necessary. This serial ID is part of a JSON record I am writing to a data file for a given group in the small groups library. Which method do I use to get the permutation group form of any given group in this library? Sandeep Murthy s.mur...@mykolab.com > On 11 Feb 2015, at 14:17, Christopher Jefferson <ca...@st-andrews.ac.uk> > wrote: > > IO_PickleToString comes from the IO package, rather than the SCSCP package. > > IO's Pickle provides a different set of methods to serialise GAP objects, > which tend to be smaller and faster to parse/unparse than openmath, but as > you saw do not implement all types. > > If you want to use open math, then use the 'OM' methods: > > gap> OMPrint(SymmetricGroup(3)); > <OMOBJ> > <OMA> > <OMS cd="permgp1" name="group"/> > <OMS cd="permutation1" name="right_compose"/> > <OMA> > <OMS cd="permut1" name="permutation"/> > <OMI>2</OMI> > <OMI>3</OMI> > <OMI>1</OMI> > </OMA> > <OMA> > <OMS cd="permut1" name="permutation"/> > <OMI>2</OMI> > <OMI>1</OMI> > </OMA> > </OMA> > </OMOBJ> > gap> OMPrint(DihedralGroup(6)); > <OMOBJ> > <OMA> > <OMS cd="pcgroup1" name="pcgroup_by_pcgscode"/> > <OMI>25</OMI> > <OMI>6</OMI> > </OMA> > </OMOBJ> > > > > > On 11/02/2015 14:05, "Sandeep Murthy" <s.mur...@mykolab.com> wrote: > >> Hi >> >> I am trying to use the IO_PickleToString() method from the SCSCP package >> to test out how GAP serialises group objects. This does not appear to be >> working as expected on the isomorphic groups Sym(3) and D_6 (dihedral >> group). >> >> gap> IO_PickleToString( SymmetricGroup( 3 ) ); >> "PRMGILIS\>2PERM\>7(1,2,3)PERM\>5(1,2)INTG\>16FAIL² >> >> This looks OK but for D_6 it fails: >> >> gap> IO_PickleToString( DihedralGroup( 6 ) ); >> Error, no method found! For debugging hints type ?Recovery from >> NoMethodFound >> Error, no 1st choice method found for `IO_Pickle' on 2 arguments called >> from >> IO_Pickle( s, obj ); called from >> <function "IO_PickleToString">( <arguments> ) >> called from read-eval loop at line 20 of *stdin* >> you can 'quit;' to quit to outer loop, or >> you can 'return;' to continue >> brk> >> >> Why is this? Both should return OpenMath strings. >> >> Sandeep >
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