indeed, it shouldn't be undefined.
either LAPACK is not built properly, either there is a problem in the call, either there is a mistake at linking time (that is unlikely as you just fixed it).
If you send me your lanczos.f90 and your Makefile, I can take a quick look.
At the same time, check that
- Code: Select all
nm /home/myname/lapack/liblapack.a | grep -i dstev
gives you a line like this:
0000000000000000 T _dstev_