/*
 * call-seq: -(b)
 *
 * Matrix subtraction
 *
 *   a - b
 *
 * +DimensionError+ is raised unless
 *
 *   a.dimensions == b.dimensions
 *
 */
VALUE rb_dmatrix_minus(VALUE self, VALUE rb)
{
    return rb_dmatrix_minus_inplace(rb_dmatrix_clone(self),rb) ;
}