Hi I am new to Fortran and am getting the below error when I try and compile using ifort 100.f90

/tmp/ifortN2Zshv.o: In function `MAIN__':
100.f90:(.text+0x25a2): undefined reference to `zgesv_'

I am not sure how to correct this and cannot find anything in my searches so any help would be appreciated.

zgesv_ is a variable or function you tried to use but didn't define. Hence "undefined reference"

How do I define it then sorry?

Through my crystal ball I see that you need to add -llapack -lblas to your linker command line.

ifort 100.f90 -L/Lib/blas_LINUX -L/Lib/lapack_LINUX
/tmp/ifort4orRdn.o: In function `MAIN__':
100.f90:(.text+0x27d2): undefined reference to `zgesv_'

I am still getting the same issue sorry

-L tells the linker where to look for libraries. It still needs to know which libraries to link in. That's what -l option is for.
add -llapack -lblas

So ifort 100.f90 -L/Lib/ -llapack_LINUX -lblas_LINUX ?


ifort 100.f90 -L/Lib/ -llapack_LINUX -lblas_LINUX
ld: cannot find -llapack_LINUX

You have to check your installation. For starters, linux filenames are case sensitive. Do you have a /Lib directory with the capital L? If so, what is the output of find /Lib -name "libblas*" ? If not, try the same with /lib instead of Lib.

find /Lib -name "libblas*"
find: /Lib: No such file or directory
h2:~> dir
total 41412
-rw-r--r-- 1 hpc12 h2 4280 Apr 15 08:14 100.f90
drwxr-xr-x 2 hpc12 h2 92 Apr 14 10:32 Lib
-rw-r--r-- 1 hpc12 h2 21193536 Apr 12 03:56 lapack_LINUX.a
-rw-r--r-- 1 hpc12 h2 21193536 Apr 12 03:56 liblapack_LINUX.a

> find: /Lib: No such file or directory
OK, you have no /Lib, meaning that -L/Lib/ points to nowhere.

h2:~> dir

This is even better. You do have lapack library. What is the directory name ( pwd at the command prompt)? BTW, I am positive that you absolutely need blas; do you have it? find / -name "libblas*"

Thanks so much this is driving me insane and I really need to work it out a.s.a.p.


Thank me when we reach some result.
Now, which directory liblapack resides in? Same for lapack and blas.
Just in case, are they valid libraries - what does nm liblapack_LINUX.a display?.
> this is driving me insane
Is this your first deadline? Relax, there are many more ahead. Insanity is not productive.

I got it working using ifort 100.f90 lapack_LINUX.a blas_LINUX.a and moving the libraries into the same directory as the code

Thanks for your help