Testing the reduction of a general 3#3-by-4#4 band matrix A to bidiagonal form is done in the following stages:
For each pair of matrix dimensions 499#499 and each selected matrix type, an 3#3-by-4#4 matrix 16#16 and an 3#3-by-500#500 matrix 67#67 are generated. The problem dimensions are as follows
| 16#16 | 3#3-by-4#4 |
| 64#64 | 3#3-by-501#501 (but 3#3-by-3#3 if nrhs 502#502 0) |
| 73#73 | 501#501-by-4#4 |
| 97#97 | 501#501-by-501#501 |
| 67#67 | 3#3-by-500#500 |
To check these calculations, the following test ratios are computed: