#include "rb_lapack.h"

extern VOID stbcon_(char* norm, char* uplo, char* diag, integer* n, integer* kd, real* ab, integer* ldab, real* rcond, real* work, integer* iwork, integer* info);


static VALUE
rblapack_stbcon(int argc, VALUE *argv, VALUE self){
  VALUE rblapack_norm;
  char norm; 
  VALUE rblapack_uplo;
  char uplo; 
  VALUE rblapack_diag;
  char diag; 
  VALUE rblapack_kd;
  integer kd; 
  VALUE rblapack_ab;
  real *ab; 
  VALUE rblapack_rcond;
  real rcond; 
  VALUE rblapack_info;
  integer info; 
  real *work;
  integer *iwork;

  integer ldab;
  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  rcond, info = NumRu::Lapack.stbcon( norm, uplo, diag, kd, ab, [:usage => usage, :help => help])\n\n\nFORTRAN MANUAL\n      SUBROUTINE STBCON( NORM, UPLO, DIAG, N, KD, AB, LDAB, RCOND, WORK, IWORK, INFO )\n\n*  Purpose\n*  =======\n*\n*  STBCON estimates the reciprocal of the condition number of a\n*  triangular band matrix A, in either the 1-norm or the infinity-norm.\n*\n*  The norm of A is computed and an estimate is obtained for\n*  norm(inv(A)), then the reciprocal of the condition number is\n*  computed as\n*     RCOND = 1 / ( norm(A) * norm(inv(A)) ).\n*\n\n*  Arguments\n*  =========\n*\n*  NORM    (input) CHARACTER*1\n*          Specifies whether the 1-norm condition number or the\n*          infinity-norm condition number is required:\n*          = '1' or 'O':  1-norm;\n*          = 'I':         Infinity-norm.\n*\n*  UPLO    (input) CHARACTER*1\n*          = 'U':  A is upper triangular;\n*          = 'L':  A is lower triangular.\n*\n*  DIAG    (input) CHARACTER*1\n*          = 'N':  A is non-unit triangular;\n*          = 'U':  A is unit triangular.\n*\n*  N       (input) INTEGER\n*          The order of the matrix A.  N >= 0.\n*\n*  KD      (input) INTEGER\n*          The number of superdiagonals or subdiagonals of the\n*          triangular band matrix A.  KD >= 0.\n*\n*  AB      (input) REAL array, dimension (LDAB,N)\n*          The upper or lower triangular band matrix A, stored in the\n*          first kd+1 rows of the array. The j-th column of A is stored\n*          in the j-th column of the array AB as follows:\n*          if UPLO = 'U', AB(kd+1+i-j,j) = A(i,j) for max(1,j-kd)<=i<=j;\n*          if UPLO = 'L', AB(1+i-j,j)    = A(i,j) for j<=i<=min(n,j+kd).\n*          If DIAG = 'U', the diagonal elements of A are not referenced\n*          and are assumed to be 1.\n*\n*  LDAB    (input) INTEGER\n*          The leading dimension of the array AB.  LDAB >= KD+1.\n*\n*  RCOND   (output) REAL\n*          The reciprocal of the condition number of the matrix A,\n*          computed as RCOND = 1/(norm(A) * norm(inv(A))).\n*\n*  WORK    (workspace) REAL array, dimension (3*N)\n*\n*  IWORK   (workspace) INTEGER array, dimension (N)\n*\n*  INFO    (output) INTEGER\n*          = 0:  successful exit\n*          < 0:  if INFO = -i, the i-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  rcond, info = NumRu::Lapack.stbcon( norm, uplo, diag, kd, ab, [:usage => usage, :help => help])\n");
      return Qnil;
    } 
  } else
    rblapack_options = Qnil;
  if (argc != 5 && argc != 5)
    rb_raise(rb_eArgError,"wrong number of arguments (%d for 5)", argc);
  rblapack_norm = argv[0];
  rblapack_uplo = argv[1];
  rblapack_diag = argv[2];
  rblapack_kd = argv[3];
  rblapack_ab = argv[4];
  if (argc == 5) {
  } else if (rblapack_options != Qnil) {
  } else {
  }

  norm = StringValueCStr(rblapack_norm)[0];
  diag = StringValueCStr(rblapack_diag)[0];
  if (!NA_IsNArray(rblapack_ab))
    rb_raise(rb_eArgError, "ab (5th argument) must be NArray");
  if (NA_RANK(rblapack_ab) != 2)
    rb_raise(rb_eArgError, "rank of ab (5th argument) must be %d", 2);
  ldab = NA_SHAPE0(rblapack_ab);
  n = NA_SHAPE1(rblapack_ab);
  if (NA_TYPE(rblapack_ab) != NA_SFLOAT)
    rblapack_ab = na_change_type(rblapack_ab, NA_SFLOAT);
  ab = NA_PTR_TYPE(rblapack_ab, real*);
  uplo = StringValueCStr(rblapack_uplo)[0];
  kd = NUM2INT(rblapack_kd);
  work = ALLOC_N(real, (3*n));
  iwork = ALLOC_N(integer, (n));

  stbcon_(&norm, &uplo, &diag, &n, &kd, ab, &ldab, &rcond, work, iwork, &info);

  free(work);
  free(iwork);
  rblapack_rcond = rb_float_new((double)rcond);
  rblapack_info = INT2NUM(info);
  return rb_ary_new3(2, rblapack_rcond, rblapack_info);
}

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

  rb_define_module_function(mLapack, "stbcon", rblapack_stbcon, -1);
}
