- ex a2 = cpy.m[r2*col+r1];
- for (unsigned c=0; c<col; ++c) {
- cpy.m[r2*col+c] -= a2 * cpy.m[r1*col+c];
- if (!cpy.m[r2*col+c].info(info_flags::numeric))
- cpy.m[r2*col+c] = cpy.m[r2*col+c].normal();
- tmp.m[r2*col+c] -= a2 * tmp.m[r1*col+c];
- if (!tmp.m[r2*col+c].info(info_flags::numeric))
- tmp.m[r2*col+c] = tmp.m[r2*col+c].normal();
+ if (!cpy.m[r2*col+r1].is_zero()) {
+ ex a2 = cpy.m[r2*col+r1];
+ // yes, there is something to do in this column
+ for (unsigned c=0; c<col; ++c) {
+ cpy.m[r2*col+c] -= a2 * cpy.m[r1*col+c];
+ if (!cpy.m[r2*col+c].info(info_flags::numeric))
+ cpy.m[r2*col+c] = cpy.m[r2*col+c].normal();
+ tmp.m[r2*col+c] -= a2 * tmp.m[r1*col+c];
+ if (!tmp.m[r2*col+c].info(info_flags::numeric))
+ tmp.m[r2*col+c] = tmp.m[r2*col+c].normal();
+ }