Zero degree variables in rings with ordering given by a matrix?

[Oleksandr]

Is the following Singular output (zero degree)correct?

> ring r = 2,(a,b), (lp, C);
> deg(a);
1
> deg(b); // 1?????!!!!
1
> ring r = 2,(a,b), (M(1,0,0,1), C); r;  // Should be the same???
//   characteristic : 2
//   number of vars : 2
//        block   1 : ordering M
//                  : names    a b
//                  : weights  1 0
//                  : weights  0 1
//        block   2 : ordering C
> deg(a);
1
> deg(b); // ZERO????? BUG?
0

btw: it seems that there are degree-relates issues (assume violations) during "std" computations wrt matrix orderings...

[Simon King]

I wouldn't call this a bug. Actually I would expect that the first row of the order matrix gives the degrees. So, in order to have both variables with degree one, I would the user expect to do:

> ring r = 2,(a,b), (M(1,1,0,1), C); r;
//   characteristic : 2
//   number of vars : 2
//        block   1 : ordering M
//                  : names    a b
//                  : weights  1 1
//                  : weights  0 1
//        block   2 : ordering C
> deg(a);
1
> deg(b);
1

[hannes]

the degree of variables is given by the first line in case of matrix orderings, and is 1 in case of block or lex orderings.