#include "rb_lapack.h"

extern VOID dtrti2_(char* uplo, char* diag, integer* n, doublereal* a, integer* lda, integer* info);


static VALUE
rblapack_dtrti2(int argc, VALUE *argv, VALUE self){
  VALUE rblapack_uplo;
  char uplo; 
  VALUE rblapack_diag;
  char diag; 
  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.dtrti2( uplo, diag, a, [:usage => usage, :help => help])\n\n\nFORTRAN MANUAL\n      SUBROUTINE DTRTI2( UPLO, DIAG, N, A, LDA, INFO )\n\n*  Purpose\n*  =======\n*\n*  DTRTI2 computes the inverse of a real upper or lower triangular\n*  matrix.\n*\n*  This is the Level 2 BLAS version of the algorithm.\n*\n\n*  Arguments\n*  =========\n*\n*  UPLO    (input) CHARACTER*1\n*          Specifies whether the matrix A is upper or lower triangular.\n*          = 'U':  Upper triangular\n*          = 'L':  Lower triangular\n*\n*  DIAG    (input) CHARACTER*1\n*          Specifies whether or not the matrix A is unit triangular.\n*          = 'N':  Non-unit triangular\n*          = 'U':  Unit triangular\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 triangular matrix A.  If UPLO = 'U', the\n*          leading n by n upper triangular part of the array A contains\n*          the upper triangular matrix, 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 the array A contains\n*          the lower triangular matrix, and the strictly upper\n*          triangular part of A is not referenced.  If DIAG = 'U', the\n*          diagonal elements of A are also not referenced and are\n*          assumed to be 1.\n*\n*          On exit, the (triangular) inverse of the original matrix, in\n*          the same storage format.\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 = -k, the k-th argument had an illegal value\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.dtrti2( uplo, diag, a, [:usage => usage, :help => help])\n");
      return Qnil;
    } 
  } else
    rblapack_options = Qnil;
  if (argc != 3 && argc != 3)
    rb_raise(rb_eArgError,"wrong number of arguments (%d for 3)", argc);
  rblapack_uplo = argv[0];
  rblapack_diag = argv[1];
  rblapack_a = argv[2];
  if (argc == 3) {
  } else if (rblapack_options != Qnil) {
  } else {
  }

  uplo = StringValueCStr(rblapack_uplo)[0];
  if (!NA_IsNArray(rblapack_a))
    rb_raise(rb_eArgError, "a (3th argument) must be NArray");
  if (NA_RANK(rblapack_a) != 2)
    rb_raise(rb_eArgError, "rank of a (3th 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*);
  diag = StringValueCStr(rblapack_diag)[0];
  {
    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__;

  dtrti2_(&uplo, &diag, &n, a, &lda, &info);

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

void
init_lapack_dtrti2(VALUE mLapack, VALUE sH, VALUE sU, VALUE zero){
  sHelp = sH;
  sUsage = sU;
  rblapack_ZERO = zero;

  rb_define_module_function(mLapack, "dtrti2", rblapack_dtrti2, -1);
}
