Installation

0) Edit make.inc to fit your system
   Important things to change are :
    - ROOT_DIR : where make.inc is
    - BLASLIB : the blas library
    - LAPACKLIB : the lapack library
    - CBLASLIB : the cblas library
    - INCLUDE : you need to point to the cblas source directory. If you do not want to build the examples, just leave it blank.
    - LASRCDIR : lapack source directory, used by the script that generates the wrapper

1) Generate the c wrapper
    make source

    This will generate the .c files for every lapack function in src, and the .h in include. Will also generate the testing wrapper code in testing (more below).

2) Compile the c wrapper
    make library

    This will build lapack_wrapper.a in lib.

3) Compile and execute the test program
    make test

    This will build libtesting_wrapper_wrapper.a in testing, and execute
the testing program.
	

Usage

    To use the LAPACK c wrapper, just link your program with the lapack_wrapper.a library in the lib directory. 
The function names of the c functions are the name of the lapack routines, lowercase, with lapack_ 
in front of them (so, DGESV will be called by lapack_dgesv). The parameters obey the following rules :
    - complex and complex*16 are respectively, arrays of size 2 of float or double.
    - scalar input parameter that are not complex are passed by value. Other parameters are passed by adress.
    - A parameter that is a LOGICAL in Fortran is a long int in C. Just set it to 1 or 0, for .TRUE. or .FALSE. .

    If in any doubt, just have a look at the lapack_function.c, where function is the name of the subroutine you want to call.
 The code is really straightforward.
	

Examples

• An example of call (DGESV) :

  int n, k, lda, ldb, info;
  double *A, *b;
  /* malloc and initialization here */
  lapack_dgesv( n, k, A, lda, ipiv, b, ldb, &info);
  		

• The code behind lapack_dgesv : lapack_dgesv.c :

  #include "../include/lapack_f77.h"
  #include "../include/lapack_enum.h"
  #include "../include/lapack_aux.h"
  
  void lapack_dgesv(const int n, const int nrhs, double * a, const int lda, int * ipiv, double * b, const int ldb, int * info )
  {
  #ifdef F77_INT
      F77_INT F77_n=n, F77_nrhs=nrhs, F77_lda=lda, F77_ldb=ldb;
      int i_local;
      F77_INT F77_ipiv[n*1];
      for(i_local=0;i_local<n*1;i_local++) {
          F77_ipiv[i_local]=(F77_INT) ipiv[i_local];
      }
      F77_INT F77_info[1];
  #else
      #define F77_n n
      #define F77_nrhs nrhs
      #define F77_lda lda
      #define F77_ipiv ipiv
      #define F77_ldb ldb
      #define F77_info info
  #endif
  
      f77_dgesv(&F77_n, &F77_nrhs, a, &F77_lda, F77_ipiv, b, &F77_ldb, F77_info);
  
  #ifdef F77_INT
      for(i_local=0;i_local<n*1;i_local++) {
          ipiv[i_local]=(int) F77_ipiv[i_local];
      }
  
      info[0]=(int) F77_info[0];
  #endif
  
  }
  		

Documentation

presentation_wrapper_C.pdf: the slides on the C wrapper used during the talk at ICL, on the 03/17/2006. May contain some useful information on the choices that were made, and on how things work.