ktye / svd Goto Github PK

In svd.go:194:

The last loop iteration is L=0, and in this case S[-1] is attempted to be accessed, which is undefined behaviour.

Additionally, after the L=0 loop, L will be decremented to L=-1, which causes the loop condition to fail, and thus exit the loop. The following loop on line 203 sets i=L=-1, and thus attempts to access t[-1], which is undefined behaviour.

Suggested fix for line 190 is to make it closer to the original Fortran:

L = k
for LL = 1; LL <= k; LL++ {
    L = k + 1 - LL

Interestingly, an older C translation of SVD from the ACM 1969 issue has the same bug, but not the original Fortran...
http://www.geocities.ws/hjsmithh/Algo358GDa.zip

Can I use your code as template and translate it to C#?