#include "rb_lapack.h"

extern VOID dpotrf_(char* uplo, integer* n, doublereal* a, integer* lda, integer* info);


static VALUE
rblapack_dpotrf(int argc, VALUE *argv, VALUE self){
  VALUE rblapack_uplo;
  char uplo; 
  VALUE rblapack_a;
  doublereal *a; 
  VALUE rblapack_info;
  integer info; 
  VALUE rblapack_a_out__;
  doublereal *a_out__;

  integer lda;
  integer n;

  VALUE rblapack_options;
  if (argc > 0 && TYPE(argv[argc-1]) == T_HASH) {
    argc--;
    rblapack_options = argv[argc];
    if (rb_hash_aref(rblapack_options, sHelp) == Qtrue) {
      printf("%s\n", "USAGE:\n  info, a = NumRu::Lapack.dpotrf( uplo, a, [:usage => usage, :help => help])\n\n\nFORTRAN MANUAL\n      SUBROUTINE DPOTRF( UPLO, N, A, LDA, INFO )\n\n*  Purpose\n*  =======\n*\n*  DPOTRF computes the Cholesky factorization of a real symmetric\n*  positive definite matrix A.\n*\n*  The factorization has the form\n*     A = U**T * U,  if UPLO = 'U', or\n*     A = L  * L**T,  if UPLO = 'L',\n*  where U is an upper triangular matrix and L is lower triangular.\n*\n*  This is the block version of the algorithm, calling Level 3 BLAS.\n*\n\n*  Arguments\n*  =========\n*\n*  UPLO    (input) CHARACTER*1\n*          = 'U':  Upper triangle of A is stored;\n*          = 'L':  Lower triangle of A is stored.\n*\n*  N       (input) INTEGER\n*          The order of the matrix A.  N >= 0.\n*\n*  A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)\n*          On entry, the symmetric matrix A.  If UPLO = 'U', the leading\n*          N-by-N upper triangular part of A contains the upper\n*          triangular part of the matrix A, and the strictly lower\n*          triangular part of A is not referenced.  If UPLO = 'L', the\n*          leading N-by-N lower triangular part of A contains the lower\n*          triangular part of the matrix A, and the strictly upper\n*          triangular part of A is not referenced.\n*\n*          On exit, if INFO = 0, the factor U or L from the Cholesky\n*          factorization A = U**T*U or A = L*L**T.\n*\n*  LDA     (input) INTEGER\n*          The leading dimension of the array A.  LDA >= max(1,N).\n*\n*  INFO    (output) INTEGER\n*          = 0:  successful exit\n*          < 0:  if INFO = -i, the i-th argument had an illegal value\n*          > 0:  if INFO = i, the leading minor of order i is not\n*                positive definite, and the factorization could not be\n*                completed.\n*\n\n*  =====================================================================\n*\n\n");
      return Qnil;
    }
    if (rb_hash_aref(rblapack_options, sUsage) == Qtrue) {
      printf("%s\n", "USAGE:\n  info, a = NumRu::Lapack.dpotrf( uplo, a, [:usage => usage, :help => help])\n");
      return Qnil;
    } 
  } else
    rblapack_options = Qnil;
  if (argc != 2 && argc != 2)
    rb_raise(rb_eArgError,"wrong number of arguments (%d for 2)", argc);
  rblapack_uplo = argv[0];
  rblapack_a = argv[1];
  if (argc == 2) {
  } else if (rblapack_options != Qnil) {
  } else {
  }

  uplo = StringValueCStr(rblapack_uplo)[0];
  if (!NA_IsNArray(rblapack_a))
    rb_raise(rb_eArgError, "a (2th argument) must be NArray");
  if (NA_RANK(rblapack_a) != 2)
    rb_raise(rb_eArgError, "rank of a (2th argument) must be %d", 2);
  lda = NA_SHAPE0(rblapack_a);
  n = NA_SHAPE1(rblapack_a);
  if (NA_TYPE(rblapack_a) != NA_DFLOAT)
    rblapack_a = na_change_type(rblapack_a, NA_DFLOAT);
  a = NA_PTR_TYPE(rblapack_a, doublereal*);
  {
    na_shape_t shape[2];
    shape[0] = lda;
    shape[1] = n;
    rblapack_a_out__ = na_make_object(NA_DFLOAT, 2, shape, cNArray);
  }
  a_out__ = NA_PTR_TYPE(rblapack_a_out__, doublereal*);
  MEMCPY(a_out__, a, doublereal, NA_TOTAL(rblapack_a));
  rblapack_a = rblapack_a_out__;
  a = a_out__;

  dpotrf_(&uplo, &n, a, &lda, &info);

  rblapack_info = INT2NUM(info);
  return rb_ary_new3(2, rblapack_info, rblapack_a);
}

void
init_lapack_dpotrf(VALUE mLapack, VALUE sH, VALUE sU, VALUE zero){
  sHelp = sH;
  sUsage = sU;
  rblapack_ZERO = zero;

  rb_define_module_function(mLapack, "dpotrf", rblapack_dpotrf, -1);
}
