On Mon, Dec 14, 2015 at 9:33 AM, Alexander Konovalov <al...@mcs.st-and.ac.uk > wrote:
> > > On 14 Dec 2015, at 14:00, Sven Reichard <sven.reich...@tu-dresden.de> > wrote: > > > > Hello Benoit, > > > > matrices are tuples of tuples, so we can use the combinatorial > > functions. As we do not want to store the complete list of matrices we > > use an iterator. > > > > gap> n := 3;; F := GF(3);; > > gap> rows := Tuples(F, n); > > gap> matrices := IteratorOfTuples(rows, n); > > gap> for matrix in matrices do > >> process(matrix); > >> od; > > > > Hope this helps. > > > > If the set of rows is too large to be stored, the set of matrices is > > likely too large to be processed. However maybe there is also a way of > > avoiding storage of the rows. > > Yes, one way to avoid storage of rows is to iterate over the full matrix > algebra: > > n := 3;; F := GF(3);; > M:=FullMatrixAlgebra(F,n); > for matrix in M do > process(matrix); > od; > Many thanks for this. Here's why I didn't find this myself when I searched for it, in case it might help future documentation work: - I searched "matrix set" and "matrix ring", not "matrix algebra". - I read the pages on matrices <http://www.gap-system.org/Manuals/doc/ref/chap24.html> and on matrix rings <http://www.math.uiuc.edu/Software/GAP-Manual/Matrix_Rings.html>, not on algebras <http://www.gap-system.org/Manuals/doc/ref/chap62.html>. - It is no clear to me which GAP objects can be readily iterated over by a "for x in object" construct. In other words, even reading the page on algebras <http://www.gap-system.org/Manuals/doc/ref/chap62.html>, it would have been not be obvious to me that I could write M:=FullMatrixAlgebra(F,n); for matrix in M do... . I did read about the concept of a "collection" but it wasn't obvious to me whether the return value of FullMatrixAlgebra is a collection, and if collections can over be iterated over like this, or if one needs to explicitly construct an iterator first. Thanks again! Benoit > > Hope this helps > Alexander > > > _______________________________________________ Forum mailing list Forum@mail.gap-system.org http://mail.gap-system.org/mailman/listinfo/forum
