[s0,s1,br] = shearfind(L,a,M,lt);
[s0,s1,br]=shearfind(L,a,M,lt) computes three numbers, the first two represent a frequency and time shear respectively. With the returned choices of \(s_0\) and \(s_1\) one can transform an initial lattice given by a, M and lt into a separable (rectangular) lattice given by
If \(s_0\) is non-zero, the transformation from general to separable lattice requires a frequency-side shear. Similarly, if \(s_1\) is non-zero, a time-side shear is required.