Location:

  http://people.sc.fsu.edu/~jburkardt/cpp_src/clapack_sc/clapack_sc.txt

Using CLAPACK to solve Linear Algebra Problems in C or C++
(as installed at FSU Department of Scientific Computing)
----------------------------------------------------------

*) the C data types must be chosen to match Fortran conventions

  Fortran wants             C uses

  double precision complex  doublecomplex
  double precision          double
  real                      float
  complex                   complex
  integer                   long int
  character                 char

*) In Fortran, an M by N array ("matrix") is stored by columns, and is 
essentially a vector.  LAPACK also allows each column to have a length LDA that 
may be greater than M.  Your life will be easier if you use LDA = M generally.  

  Declare:  double precision A(4,3)    double A[4*3];

  Init:     data A /                   double A = {
           & 11, 21, 31, 41,           11, 21, 31, 41,
           & 12, 22, 32, 42,           12, 22, 32, 42,
           & 13, 23, 33, 43 /          13, 23, 33, 43 };

  A(I,J):  A(I,J) = 10 * I + J         A[I+J*LDA] = 10 * I + J
                                       A[I+J*M]   = 10 + I + J (if LDA = M )
 
*) If the official name of a LAPACK function is "DGESV", your C program must 
call it using lower case letters, and a final underscore:

  call dgesv ( arg1, arg2, ... )       dgesv_ ( arg1, arg2, ... );

*) All scalar arguments must be passed by reference (with an AMPERSAND
preceding their names).  Vectors and matrices are passed in the usual way.

  FORTRAN: call dgesv (   n,  nrhs, a,  lda, ipiv, b,  ldb,  info )
  C:            dgesv_ ( &n, &nrhs, a, &lda, ipiv, b, &ldb, &info ):

  Note in particular that you CANNOT PASS CONSTANT VALUES AS ARGUMENTS:

  Won't work!:  dgesv_ (  5,    1,  a, &lda, ipiv, b, &ldb, &info );

*) Your program must have the CLAPACK include statement:

  # include "clapack.h"

*) To compile (but not load) your calling program:

  gcc -c -I/usr/common/clapack myprog.c 
  g++ -c -I/usr/common/clapack myprog.cpp

*) To load your compiled program:

  gcc myprog.o -L/usr/common/clapack -lclapack -lm
  g++ myprog.o -L/usr/common/clapack -lclapack -lm

*) To run your loaded program:

  ./a.out

See also: http://people.sc.fsu.edu/~jburkardt/cpp_src/clapack_sc/clapack_sc.html