The new module arrlib replaces the old duo arr and
The differences are:
arr/geom supports uppercase names like XYf, XYZi, M33f
etc. Also untyped names like rot and xlat. Special (float) matrices
can be constructed by Ident, Identf and Identd.
arrlib supports only lowercase names like xyf, xyzi, m33f
etc. rotf and xlatf replaces the untyped names. The larger matrices
are generated by identfMat and identdMat.
Otherwise arrlib has a more complete set of functions,
operators etc., i.e. extensions to arr/geom.