Multiply the given matrix with this Vector3d by assuming a third row in the matrix of <code>(0, 0, 1)</code> and store the result in <code>this</code>.
@param mat the matrix @return this
See Implementation
Multiply the given matrix with this Vector3d by assuming a third row in the matrix of <code>(0, 0, 1)</code> and store the result in <code>this</code>.
@param mat the matrix @return this