I'd deprecate `mul` and prefer `scale`, personally.  Vector multiplication (which is what `mul(a, b, c)` looks like it might be doing from its name) usually means dot product or cross product.  The `scale(a, b, c)` doesn't have any strong connotations to me (so it means what the javadoc says).  On the other hand, these are just conventions inherited from long-ago middle school math class, so if yours are different then keep what you've got.