Computes the condition number of the sum function.
[c,y] = condnb_sumcond ( x )
a n-by-m matrix of doubles
a n-by-m matrix of doubles, the condition number
a n-by-m, matrix of doubles, the function values
Computes the condition number of the sum function. The sum function has a large condition number if the sum is small, but the values are of opposite sign and of very different magnitudes.
where