L=dgtlength(Ls,a,M); L=dgtlength(Ls,a,M,lt);
dgtlength(Ls,a,M) returns the length of a Gabor system that is long enough to expand a signal of length Ls. Please see the help on dgt for an explanation of the parameters a and M.
If the returned length is longer than the signal length, the signal will be zero-padded by dgt.
A valid transform length must be divisable by both a and M. This means that the minumal admissable transform length is
Lsmallest = lcm(a,M);
and all valid transform lengths are multipla of Lsmallest
dgtlength(Ls,a,M,lt) does as above for a non-separable lattice with lattice-type lt. For non-separable lattices, there is the additinal requirement on the transform length, that the structure of the lattice must be periodic. This gives a minimal transform length of
Lsmallest = lcm(a,M)*lt(2);