[GRASS5] Error to compile i.fft

[Markus Neteler]

Hi,

again on the "gmath"/numerical functions issue...
I need a recommendation.

Currently we face following situation:
 
 - src/libes/gmath/ has been written by David to support LAPACK/BLAS
   (it contains wrapper functions)
 - we have spreading around numerous files containing various numerical
   functions like fft, ifft, matrix operations etc.

My intention is to assemble all functionality in one library. So
I started to migrate all such functions into src/libes/gmath/ 
(as I did for i.fft and accidentially already uploaded).

A problem arises on those machines, which don't have LAPACK/BLAS and "g2c"
(requirement, which is the former f2c.h) installed.
For example you will get, when compiling "gmath":
  src/include/la.h:28: g2c.h: No such file or directory
  make: *** [OBJ.sparc-sun-solaris2.6/la.o] Error 1

Two solutions may the at our choice:
 
  (1) split the library into two libraries
         a) LAPACK/BLAS routines
         b) others
  (2) add some clever mechanism to selectively compile with/without
      LAPACK/BLAS support. So far "configure" checks already the presence
      of LAPACK/BLAS.

I would vote for (2), but don't know how to implement it. Must be some
ifdef's around "la.h"?

Assistance is welcome,

 Markus

PS: In Russia they have developed a parallelized version of s.surf.idw
    which is available here (MPI):
    http://www.tigers.ru/grass_docs/progs/DESCRIPTION.html
    Where to store this module in CVS?