IsListOfIntegers(
list ) P
IsListOfIntegers(
list )
returns IsSubset(Integers,
list )
if list
is a dense list and false
otherwise.
List2Tuples(
list,
int ) O
If Size(
list )
is divisible by int, List2Tuples(
list,
int)
returns a list list2 of size int such that
Concatenation(
list2 )=
list and every element of list2 has the
same size.
gap> List2Tuples([1..6],2); [ [ 1, 2, 3 ], [ 4, 5, 6 ] ]
MatTimesTransMat(
mat ) O
does the same as mat
*TransposedMat(
mat )
but uses slightly less
space and time for large matrices.
PartitionByFunctionNF(
list,
f ) O
PartitionByFunctionNF(
list,
f )
partitions the list list
according to the values of the function f defined on list.
If f returns fail
for some element of list,
PartitionByFunctionNF(
list,
f )
enters a break loop.
Leaving the break loop with 'return;' is safe because
PartitionByFunctionNF
treats fail
as all other results of f.
PartitionByFunction(
list,
f ) O
PartitionByFunction(
list,
f )
partitions the list list
according to the values of the function f defined on list.
All elements, for which f returns fail
are omitted, so
PartitionByFunction
does not necessarily return a partition.
If InfoLevel(InfoRDS)
indexInfoRDS@ttInfoRDS is at least 2, the number of
elements for which f returns fail
is shown
(if fail
is returned at all).
gap> PartitionByFunctionNF([-1..5],x->x^2); [ [ 0 ], [ -1, 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ] ] gap> test:=function(x) > if x>0 then return Sqrt(x); > else return fail; > fi; > end; function( x ) ... end gap> PartitionByFunction([-1..5],test); [ [ 1 ], [ 4 ], [ 5 ], [ 2 ], [ 3 ] ] gap> SetInfoLevel(InfoRDS,2); gap> PartitionByFunction([-1..5],test); #I -2- [ [ 1 ], [ 4 ], [ 5 ], [ 2 ], [ 3 ] ] gap> PartitionByFunctionNF([-1..5],test); Error, function returned <fail> called from ... brk> return; [ [ 1 ], [ 4 ], [ 5 ], [ 2 ], [ 3 ], [ -1, 0 ] ]
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