gives the Smith normal form decomposition of an integer matrix.
.wl リファレンスとの相違: `SchurDecomposition` and `SmithDecomposition` factors are non-unique
SmithDecomposition[m]
SmithDecomposition[{{1, 0}, {0, 1}}]
→ {{{1, 0}, {0, 1}}, {{1, 0}, {0, 1}}, {{1, 0}, {0, 1}}}