#include "rb_lapack.h"

extern VOID zhetd2_(char* uplo, integer* n, doublecomplex* a, integer* lda, doublereal* d, doublereal* e, doublecomplex* tau, integer* info);


static VALUE
rblapack_zhetd2(int argc, VALUE *argv, VALUE self){
  VALUE rblapack_uplo;
  char uplo; 
  VALUE rblapack_a;
  doublecomplex *a; 
  VALUE rblapack_d;
  doublereal *d; 
  VALUE rblapack_e;
  doublereal *e; 
  VALUE rblapack_tau;
  doublecomplex *tau; 
  VALUE rblapack_info;
  integer info; 
  VALUE rblapack_a_out__;
  doublecomplex *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  d, e, tau, info, a = NumRu::Lapack.zhetd2( uplo, a, [:usage => usage, :help => help])\n\n\nFORTRAN MANUAL\n      SUBROUTINE ZHETD2( UPLO, N, A, LDA, D, E, TAU, INFO )\n\n*  Purpose\n*  =======\n*\n*  ZHETD2 reduces a complex Hermitian matrix A to real symmetric\n*  tridiagonal form T by a unitary similarity transformation:\n*  Q' * A * Q = T.\n*\n\n*  Arguments\n*  =========\n*\n*  UPLO    (input) CHARACTER*1\n*          Specifies whether the upper or lower triangular part of the\n*          Hermitian matrix A is stored:\n*          = 'U':  Upper triangular\n*          = 'L':  Lower triangular\n*\n*  N       (input) INTEGER\n*          The order of the matrix A.  N >= 0.\n*\n*  A       (input/output) COMPLEX*16 array, dimension (LDA,N)\n*          On entry, the Hermitian 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*          On exit, if UPLO = 'U', the diagonal and first superdiagonal\n*          of A are overwritten by the corresponding elements of the\n*          tridiagonal matrix T, and the elements above the first\n*          superdiagonal, with the array TAU, represent the unitary\n*          matrix Q as a product of elementary reflectors; if UPLO\n*          = 'L', the diagonal and first subdiagonal of A are over-\n*          written by the corresponding elements of the tridiagonal\n*          matrix T, and the elements below the first subdiagonal, with\n*          the array TAU, represent the unitary matrix Q as a product\n*          of elementary reflectors. See Further Details.\n*\n*  LDA     (input) INTEGER\n*          The leading dimension of the array A.  LDA >= max(1,N).\n*\n*  D       (output) DOUBLE PRECISION array, dimension (N)\n*          The diagonal elements of the tridiagonal matrix T:\n*          D(i) = A(i,i).\n*\n*  E       (output) DOUBLE PRECISION array, dimension (N-1)\n*          The off-diagonal elements of the tridiagonal matrix T:\n*          E(i) = A(i,i+1) if UPLO = 'U', E(i) = A(i+1,i) if UPLO = 'L'.\n*\n*  TAU     (output) COMPLEX*16 array, dimension (N-1)\n*          The scalar factors of the elementary reflectors (see Further\n*          Details).\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*  Further Details\n*  ===============\n*\n*  If UPLO = 'U', the matrix Q is represented as a product of elementary\n*  reflectors\n*\n*     Q = H(n-1) . . . H(2) H(1).\n*\n*  Each H(i) has the form\n*\n*     H(i) = I - tau * v * v'\n*\n*  where tau is a complex scalar, and v is a complex vector with\n*  v(i+1:n) = 0 and v(i) = 1; v(1:i-1) is stored on exit in\n*  A(1:i-1,i+1), and tau in TAU(i).\n*\n*  If UPLO = 'L', the matrix Q is represented as a product of elementary\n*  reflectors\n*\n*     Q = H(1) H(2) . . . H(n-1).\n*\n*  Each H(i) has the form\n*\n*     H(i) = I - tau * v * v'\n*\n*  where tau is a complex scalar, and v is a complex vector with\n*  v(1:i) = 0 and v(i+1) = 1; v(i+2:n) is stored on exit in A(i+2:n,i),\n*  and tau in TAU(i).\n*\n*  The contents of A on exit are illustrated by the following examples\n*  with n = 5:\n*\n*  if UPLO = 'U':                       if UPLO = 'L':\n*\n*    (  d   e   v2  v3  v4 )              (  d                  )\n*    (      d   e   v3  v4 )              (  e   d              )\n*    (          d   e   v4 )              (  v1  e   d          )\n*    (              d   e  )              (  v1  v2  e   d      )\n*    (                  d  )              (  v1  v2  v3  e   d  )\n*\n*  where d and e denote diagonal and off-diagonal elements of T, and vi\n*  denotes an element of the vector defining H(i).\n*\n*  =====================================================================\n*\n\n");
      return Qnil;
    }
    if (rb_hash_aref(rblapack_options, sUsage) == Qtrue) {
      printf("%s\n", "USAGE:\n  d, e, tau, info, a = NumRu::Lapack.zhetd2( 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_DCOMPLEX)
    rblapack_a = na_change_type(rblapack_a, NA_DCOMPLEX);
  a = NA_PTR_TYPE(rblapack_a, doublecomplex*);
  {
    na_shape_t shape[1];
    shape[0] = n;
    rblapack_d = na_make_object(NA_DFLOAT, 1, shape, cNArray);
  }
  d = NA_PTR_TYPE(rblapack_d, doublereal*);
  {
    na_shape_t shape[1];
    shape[0] = n-1;
    rblapack_e = na_make_object(NA_DFLOAT, 1, shape, cNArray);
  }
  e = NA_PTR_TYPE(rblapack_e, doublereal*);
  {
    na_shape_t shape[1];
    shape[0] = n-1;
    rblapack_tau = na_make_object(NA_DCOMPLEX, 1, shape, cNArray);
  }
  tau = NA_PTR_TYPE(rblapack_tau, doublecomplex*);
  {
    na_shape_t shape[2];
    shape[0] = lda;
    shape[1] = n;
    rblapack_a_out__ = na_make_object(NA_DCOMPLEX, 2, shape, cNArray);
  }
  a_out__ = NA_PTR_TYPE(rblapack_a_out__, doublecomplex*);
  MEMCPY(a_out__, a, doublecomplex, NA_TOTAL(rblapack_a));
  rblapack_a = rblapack_a_out__;
  a = a_out__;

  zhetd2_(&uplo, &n, a, &lda, d, e, tau, &info);

  rblapack_info = INT2NUM(info);
  return rb_ary_new3(5, rblapack_d, rblapack_e, rblapack_tau, rblapack_info, rblapack_a);
}

void
init_lapack_zhetd2(VALUE mLapack, VALUE sH, VALUE sU, VALUE zero){
  sHelp = sH;
  sUsage = sU;
  rblapack_ZERO = zero;

  rb_define_module_function(mLapack, "zhetd2", rblapack_zhetd2, -1);
}
