I'm trying to use the diagonalization routine TQLI, which calls the function PYTHAG from a module called NR. The problem is that NR seem to be an interface only, which uses another module called NRTYPE. Except there is no function PYTHAG anywhere. So does anyone know where I can find PYTHAG??

Hi,

pythag.f90 is in the same recipes directory as tqli.f90. Its interface is in the module nr.f90 to allow separate compilation. In the text, pythag.f90 appears after svdcmp, on p. 1029.

Saul Teukolsky