The rank of a matrix depends on the modulus used:
With ordinary arithmetic,
m has the full rank of 3:
With arithmetic modulo 5, the rank is only 2:
The setting of
Tolerance can affect the estimated rank for numerical ill-conditioned matrices:
With machine arithmetic the default is to consider elements that are too small as zero:
With zero tolerance even small terms may be taken into account:
With a tolerance greater than the pivot in the middle row, the last two rows are considered zero: