#673 closed bug (fixed)
rank incorrect over integers
Reported by: | Owned by: | somebody | |
---|---|---|---|
Priority: | minor | Milestone: | 4-1-0 and higher |
Component: | singular-kernel | Version: | 4-0-1 |
Keywords: | rank integers incorrect | Cc: |
Description
Observed by Simon Brandhorst:
- the rank function is incorrect over integers
Failing example:
ring QQ = 0,x,dp; intmat m[2][2] = 4, 6, -10, -15; rank(m); // =1, ok? ring ZZ = integer,x,dp; rank(m); //=2, wrong!!! expected 1, hint: (4 ,-10)-(6,-15) = (-2, 5) ; (4,-10)= -2*(-2,5); (6,-15)=-3*(-2,5); def stdm = matrix(std(module(matrix(m)))); stdm; ncols(stdm); //=1
output:
> ring QQ = 0,x,dp; > intmat m[2][2] = 4, 6, -10, -15; > rank(m); // =1, ok? 1 > ring ZZ = integer,x,dp; > rank(m); //=2, wrong!!! 2 > def stdm = matrix(std(module(matrix(m)))); > stdm; stdm[1,1]=-2 stdm[2,1]=5 > ncols(stdm); //=1 1 >
Remark: 'ludecomp()' is disabled over rings, but 'rank()' is not
- it is unexpected that rank(m) depends on current ring instead on type of matrix m (intmat vs matrix).
Note: See
TracTickets for help on using
tickets.
fixed with a62aaf77249f98fad26ba201fd0f646f392e5fcc concerning 2: (beside that it contradicts the condition for this tracker (only one issue per ticket)),no.