About confusion.m function

Reading confusion.m function of nnet toolbox I observed the FNR and FPR computations. Matlab code shows:

per(i,1) = sum((yi ~= 1)&(ti == 1))/sum(yi ~= 1);

per(i,2) = sum((yi == 1)&(ti ~= 1))/sum(yi == 1);

The first line computes FNR and the second computes FPR

I have read some literature and I think computations should be:

per(i,1) = sum((yi ~= 1)&(ti == 1))/sum(yi == 1);

per(i,2) = sum((yi == 1)&(ti ~= 1))/sum(yi ~= 1);

And also, the denominator in both equations should be ti instead of yi?

am I correct? need help...!

Fernando