Linking LAPACK and Fortran 90

[alemundo]

I am running 12.04 on a 64-bit machine and I am trying to compile a Fortran 90 program. I installed the LAPACK files through Synaptic but when I try to compile the program I am told:
"Fatal Error Can't find module file 'lapack.mod' for reading at (1): No such file or directory."

My original attempt to link:
gfortran test.f90 -L/usr/lib/lapack -liblapack.a

The file locations are correct. I'm just happy to take whatever information you can offer.

 

[xwb]

Find out where lapack.mod lives - say it lives in /xxx/yyy/zzz. Change your build line to

gfortran test.f90 -I/xxx/yyy/zzz -L/usr/lib/lapack -llapack

You do know that the executable will be called a.out unless you specify a -o parameter.
It is not a good idea on Linux to name your programs test since there is a sh/bash command called test.

 

[alemundo]

Alright, xwb. So I typed "whereis lapack.mod" and my output was "/usr/lib/lapack /usr/share/man/man3/lapack.3lapack.gz" However, I do not see the plain lapack.mod file when I visit them.

I did try the new build line anyway with both the directories shown pointing to the same place but I got the same error that I had before.

Noted!

 

[xwb]

Could you modify the test program and remove the use lapack statement? At a guess the lapack library is written as f77: not f90 so there probably isn't a mod file.

 

[alemundo]

In that case should I just find the f90 version for it?

 

[salgerman]

alemundo:

did you see the difference between your command and xwb's ?

when using a library, you do not specify the entire name "-liblapack.a"; you simply pass the "-l" flag followed by the name of the library without the prefix "lib" and without the extension ".a"

So, for starters, try a command along the lines of:

gfortran -llapack -L/usr/lib/lapack myprogram.f90

and the actual file liblapack.a must be in the directory specified by -L