The problem with Tobias' memory leak in the GAP interface seems to be that
GAP keeps a log of all interactive commands in the undocumented variable
"CommandLineHistory". This quickly fills up the available RAM if things are
done in a tight loop:
sage: G = DihedralGroup(6)
sage: tbl = G.character_table()
sage: gap.eval('Print(CommandLineHistory)')
'[ 124, "LoadPackage(\\"GAPDoc\\");", "LoadPackage(\\"ctbllib\\");", \n
"LoadPackage(\\"sonata\\");", "LoadPackage(\\"guava\\");", \n
"LoadPackage(\\"factint\\");", "LoadPackage(\\"gapdoc\\");", \n
"LoadPackage(\\"grape\\");", "LoadPackage(\\"design\\");", \n
"LoadPackage(\\"toric\\");", "LoadPackage(\\"laguna\\");", \n
"LoadPackage(\\"braid\\");", \n
"SaveWorkspace(\\"/home/vbraun/.sage/gap/tmpim5yyp\\");", \n
"$sage1:=Group([PermList([2, 3, 4, 5, 6, 1]), PermList([6, 5, 4, 3, 2,
1])]);;", "__SAGE_LAST__ := \\"__SAGE_LAST__\\";;",
"ConjugacyClasses($sage1);", \n "last;", "$sage2:=last;;", "__SAGE_LAST__
:= \\"__SAGE_LAST__\\";;", \n "Length($sage2);", "last;",
"$sage3:=last;;", "Print($sage3);", \n "__SAGE_LAST__ :=
\\"__SAGE_LAST__\\";;", "Irr($sage1);", "last;", \n "$sage3:=last;;",
"$sage4:=$sage3[1][1];;", "$sage5:=$sage3[1][2];;", \n
"$sage6:=$sage3[1][3];;", "$sage7:=$sage3[1][4];;", \n
"$sage8:=$sage3[1][5];;", "$sage9:=$sage3[1][6];;", \n
"$sage10:=$sage3[2][1];;", "$sage11:=$sage3[2][2];;", \n
"$sage12:=$sage3[2][3];;", "$sage13:=$sage3[2][4];;", \n
"$sage14:=$sage3[2][5];;", "$sage15:=$sage3[2][6];;", \n
"$sage16:=$sage3[3][1];;", "$sage17:=$sage3[3][2];;", \n
"$sage18:=$sage3[3][3];;", "$sage19:=$sage3[3][4];;", \n
"$sage20:=$sage3[3][5];;", "$sage21:=$sage3[3][6];;", \n
"$sage22:=$sage3[4][1];;", "$sage23:=$sage3[4][2];;", \n
"$sage24:=$sage3[4][3];;", "$sage25:=$sage3[4][4];;", \n
"$sage26:=$sage3[4][5];;", "$sage27:=$sage3[4][6];;", \n
"$sage28:=$sage3[5][1];;", "$sage29:=$sage3[5][2];;", \n
"$sage30:=$sage3[5][3];;", "$sage31:=$sage3[5][4];;", \n
"$sage32:=$sage3[5][5];;", "$sage33:=$sage3[5][6];;", \n
"$sage34:=$sage3[6][1];;", "$sage35:=$sage3[6][2];;", \n
"$sage36:=$sage3[6][3];;", "$sage37:=$sage3[6][4];;", \n
"$sage38:=$sage3[6][5];;", "$sage39:=$sage3[6][6];;", \n "__SAGE_LAST__
:= \\"__SAGE_LAST__\\";;", "Flat($sage3);", "last;", \n "$sage40:=last;;",
"__SAGE_LAST__ := \\"__SAGE_LAST__\\";;", \n "Conductor($sage40);",
"last;", "$sage41:=last;;", "$sage40:=1;;", \n "$sage40:=0;;",
"__SAGE_LAST__ := \\"__SAGE_LAST__\\";;", "gen($sage40);", \n
"__SAGE_LAST__ := \\"__SAGE_LAST__\\";;", "gen();",
"$sage40:=_an_element_;;",\n "$sage42:=pi;;", "$sage43:=1.2;;",
"Print($sage41);", "$sage44:=1*I;;", \n "$sage45:=CyclotomicField(1);;",
"$sage46:=GeneratorsOfField($sage45)[1];;",\n "__SAGE_LAST__ :=
\\"__SAGE_LAST__\\";;", "is_field();", "Print($sage4);", \n
"Print($sage5);", "Print($sage6);", "Print($sage7);", "Print($sage8);", \n
"Print($sage9);", "Print($sage10);", "Print($sage11);", "Print($sage12);",
\n "Print($sage13);", "Print($sage14);", "Print($sage15);",
"Print($sage16);", \n "Print($sage17);", "Print($sage18);",
"Print($sage19);", "Print($sage20);", \n "Print($sage21);",
"Print($sage22);", "Print($sage23);", "Print($sage24);", \n
"Print($sage25);", "Print($sage26);", "Print($sage27);",
"Print($sage28);", \n "Print($sage29);", "Print($sage30);",
"Print($sage31);", "Print($sage32);", \n "Print($sage33);",
"Print($sage34);", "Print($sage35);", "Print($sage36);", \n
"Print($sage37);", "Print($sage38);", "Print($sage39);", \n
"Print(CommandLineHistory);" ]'
On Thursday, February 13, 2014 1:24:14 PM UTC, Tobias Weich wrote:
>
> Dear all,
>
> Im doing some numerics on symmetry reduced PDEs. For this it is necessary
> to calculate the cahracters of some permutation group elments. In a precise
> example I call
>
> character(g**k)
>
>
> where character is a character of the DihedralGroup(6), g an element of
> this Group and k an integer in range(10). If the programm runs a long time
> then I get in a nonreprodicible manner different Errorrs from gap like
>
> File
> "/usr/local/sage/sage-5.12/local/lib/python2.7/site-packages/sage/groups/class_function.py"
> , line 279, in __call__ return self._base_ring(gap(g)._operation("^", self
> ._gap_classfunction))
> File
> "/usr/local/sage/sage-5.12/local/lib/python2.7/site-packages/sage/interfaces/interface.py"
> , line 1076, in _operation raise TypeError, msg
> TypeError: Gap produced error output
> Error, exceeded the permitted memory (`-o' command line option)
>
> executing $sage21:=$sage63 ^ $sage87;;
>
> Or
>
> ** Gap crashed or quit executing '$sage53:=PermList([5, 6, 4, 2, 3, 1]);;'
> **
> Restarting Gap and trying again
> Error in lines 1-3
> Traceback (most recent call last):
> File
> "/projects/323aa7f2-3ee3-43cd-ac05-4a21e6b0c3f6/.sagemathcloud/sage_server.py"
> , line 733, in execute
> exec compile(block+'\n', '', 'single') in namespace, locals
> File "", line 2, in <module>
> .......
> .some traceback of my nested funcion calls
> ......
>
> File
> "/usr/local/sage/sage-5.12/local/lib/python2.7/site-packages/sage/groups/class_function.py"
> , line 279, in __call__
> return self._base_ring(gap(g)._operation("^", self._gap_classfunction
> ))
> File
> "/usr/local/sage/sage-5.12/local/lib/python2.7/site-packages/sage/interfaces/interface.py"
> , line 1076, in _operation
> raise TypeError, msg
> TypeError: Gap produced error output
> Error, Variable: '$sage33' must have a value
>
> executing $sage45:=$sage53 ^ $sage33;;
>
> Does anybody have a clue what is happening here? Are the group elements
> not supposed to be exponentiated a lot of times independently?
>
> A possible workaround would probably be to calculate all the needed
> characters of all group elements once and store them instead of
> recalculating. I still would love to know what is going wrong here.
>
> Thanks in advance for your replies,
>
> Best,
> Tobias
>
> P.S.
> All this happend on the sage installation on sagemath-cloud if this is of
> importance.
>
>
>
>
>
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