/*
  dht.c
  Ruby/GSL: Ruby extension library for GSL (GNU Scientific Library)
    (C) Copyright 2001-2004 by Yoshiki Tsunesada

  Ruby/GSL is free software: you can redistribute it and/or modify it
  under the terms of the GNU General Public License.
  This library is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY.
*/

#include "rb_gsl.h"
#include "rb_gsl_array.h"
#include "rb_gsl_common.h"
#include <gsl/gsl_dht.h>

static VALUE rb_gsl_dht_alloc(VALUE klass, VALUE size)
{
  gsl_dht *t = NULL;
  CHECK_FIXNUM(size);
  t = gsl_dht_alloc(FIX2INT(size));
  return Data_Wrap_Struct(klass, 0, gsl_dht_free, t);
}

static VALUE rb_gsl_dht_new(int argc, VALUE *argv, VALUE klass)
{
  gsl_dht *t = NULL;
  switch (argc) {
  case 1:
    CHECK_FIXNUM(argv[0]);
    t = gsl_dht_alloc(FIX2INT(argv[0]));
    break;
  case 3:
    CHECK_FIXNUM(argv[0]);
    Need_Float(argv[1]); Need_Float(argv[2]);
    t = gsl_dht_new(FIX2INT(argv[0]), NUM2DBL(argv[1]), NUM2DBL(argv[2]));
   break;
  default:
    rb_raise(rb_eArgError, "wrong number of arguments (%d for 1 or 3)", argc);
    break;
  }
  return Data_Wrap_Struct(klass, 0, gsl_dht_free, t);
}

static VALUE rb_gsl_dht_init(VALUE obj, VALUE nu, VALUE xmax)
{
  gsl_dht *t = NULL;
  Need_Float(nu); Need_Float(xmax);
  Data_Get_Struct(obj, gsl_dht, t);
  gsl_dht_init(t, NUM2DBL(nu), NUM2DBL(xmax));
  return obj;
}

static VALUE rb_gsl_dht_apply(int argc, VALUE *argv, VALUE obj)
{
  gsl_dht *t = NULL;
  gsl_vector *vin = NULL, *vout = NULL;
  switch (argc) {
  case 2:
    Data_Get_Struct(obj, gsl_dht, t);
    Data_Get_Vector(argv[0], vin);
    Data_Get_Vector(argv[1], vout);
    return INT2FIX(gsl_dht_apply(t, vin->data, vout->data));
    break;
  case 1:
    Data_Get_Struct(obj, gsl_dht, t);
    Data_Get_Vector(argv[0], vin);
    vout = gsl_vector_alloc(vin->size);
    gsl_dht_apply(t, vin->data, vout->data);
    return Data_Wrap_Struct(VECTOR_ROW_COL(argv[0]), 0, gsl_vector_free, vout);
    break;
  default:
    rb_raise(rb_eArgError, "wrong number of arguments (%d for 1 or 2)", argc);
    break;
  }
  return Qnil; /* never reach here */
}

static VALUE rb_gsl_dht_xk_sample(VALUE obj, VALUE n, 
			       double (*sample)(const gsl_dht*, int))
{
  gsl_dht *t = NULL;
  gsl_vector_int *vi;
  gsl_vector *v;
  size_t i, size;
  int nn;
  VALUE ary;
  double val;
  Data_Get_Struct(obj, gsl_dht, t);
  if (CLASS_OF(n) == rb_cRange) n = rb_gsl_range2ary(n);
  switch (TYPE(n)) {
  case T_FIXNUM:
    return rb_float_new((*sample)(t, FIX2INT(n)));
    break;
  case T_ARRAY:
    size = RARRAY(n)->len;
    ary = rb_ary_new2(size);
    for (i = 0; i < size; i++) {
      nn = FIX2INT(rb_ary_entry(n, i));
      val = (*sample)(t, nn);
      rb_ary_store(ary, i, rb_float_new(val));
    }
    return ary;
    break;
  default:
    CHECK_VECTOR_INT(n);
    Data_Get_Struct(n, gsl_vector_int, vi);
    v = gsl_vector_alloc(vi->size);
    for (i = 0; i < v->size; i++) {
      nn = gsl_vector_int_get(vi, i);
      val = (*sample)(t, nn);
      gsl_vector_set(v, i, val);
    }
    return Data_Wrap_Struct(cgsl_vector, 0, gsl_vector_free, v);
  }
  return Qnil;
}

static VALUE rb_gsl_dht_x_sample(VALUE obj, VALUE n)
{
  return rb_gsl_dht_xk_sample(obj, n, gsl_dht_x_sample);
}

static VALUE rb_gsl_dht_k_sample(VALUE obj, VALUE n)
{
  return rb_gsl_dht_xk_sample(obj, n, gsl_dht_k_sample);
}

static VALUE rb_gsl_dht_j(VALUE obj)
{
  gsl_dht *t = NULL;
  gsl_vector_view *v = NULL;
  Data_Get_Struct(obj, gsl_dht, t);
  v = rb_gsl_make_vector_view(t->j, (t->size+2), 1);
  return Data_Wrap_Struct(cgsl_vector_view_ro, 0, free, v);
}

static VALUE rb_gsl_dht_zero(VALUE obj)
{
  gsl_dht *t = NULL;
  gsl_vector_view *v = NULL;
  Data_Get_Struct(obj, gsl_dht, t);
  v = rb_gsl_make_vector_view(t->j+1, (t->size+1), 1);
  return Data_Wrap_Struct(cgsl_vector_view_ro, 0, free, v);
}

static VALUE rb_gsl_dht_Jjj(VALUE obj)
{
  gsl_dht *t = NULL;
  gsl_vector_view *v = NULL;
  Data_Get_Struct(obj, gsl_dht, t);
  v = rb_gsl_make_vector_view(t->Jjj, t->size*(t->size+1)/2, 1);
  return Data_Wrap_Struct(cgsl_vector_view_ro, 0, free, v);
}

static VALUE rb_gsl_dht_sample(int argc, VALUE *argv, VALUE obj)
{
  gsl_dht *t = NULL;
  gsl_matrix *mm = NULL;
  size_t n, m;
  double val;
  Data_Get_Struct(obj, gsl_dht, t);
  switch (argc) {
  case 0:
    mm = gsl_matrix_alloc(t->size, t->size);
    for (n = 0; n < t->size; n++) {
      for (m = 0; m < t->size; m++) {
	val =  t->j[n+1]*gsl_dht_x_sample(t, m)/t->xmax;
	gsl_matrix_set(mm, n, m, val);
      }
    }
    return Data_Wrap_Struct(cgsl_matrix, 0, gsl_matrix_free, mm);
    break;
  case 2:
    n = FIX2INT(argv[0]);
    m = FIX2INT(argv[1]);
    val = t->j[n+1]*gsl_dht_x_sample(t, m)/t->xmax;
    return rb_float_new(val);
    break;
  default:
    rb_raise(rb_eArgError, "wrong number of arguments (%d for 0 or 2)", argc);
    break;
  }
  return Qnil;
}

static VALUE rb_gsl_dht_num(int argc, VALUE *argv, VALUE obj)
{
  gsl_dht *t = NULL;
  gsl_matrix *mm = NULL;
  size_t n, m;
  double val;
  Data_Get_Struct(obj, gsl_dht, t);
  switch (argc) {
  case 0:
    mm = gsl_matrix_alloc(t->size, t->size);
    for (n = 0; n < t->size; n++) {
      for (m = 0; m < t->size; m++) {
	val = gsl_sf_bessel_Jnu(t->nu, t->j[n+1]*gsl_dht_x_sample(t, m)/t->xmax);
	gsl_matrix_set(mm, n, m, val);
      }
    }
    return Data_Wrap_Struct(cgsl_matrix, 0, gsl_matrix_free, mm);
    break;
  case 2:
    n = FIX2INT(argv[0]);
    m = FIX2INT(argv[1]);
    val = gsl_sf_bessel_Jnu(t->nu, t->j[n+1]*gsl_dht_x_sample(t, m)/t->xmax);
    return rb_float_new(val);
    break;
  default:
    rb_raise(rb_eArgError, "wrong number of arguments (%d for 0 or 2)", argc);
    break;
  }
  return Qnil;
}

static VALUE rb_gsl_dht_J2(VALUE obj)
{
  gsl_dht *t = NULL;
  gsl_vector_view *v = NULL;
  Data_Get_Struct(obj, gsl_dht, t);
  v = rb_gsl_make_vector_view(t->J2, t->size+1, 1);
  return Data_Wrap_Struct(cgsl_vector_view_ro, 0, free, v);
}

static VALUE rb_gsl_dht_den(VALUE obj)
{
  gsl_dht *t = NULL;
  gsl_vector_view *v = NULL;
  Data_Get_Struct(obj, gsl_dht, t);
  v = rb_gsl_make_vector_view(t->J2+1, t->size, 1);
  return Data_Wrap_Struct(cgsl_vector_view_ro, 0, free, v);
}

static VALUE rb_gsl_dht_size(VALUE obj)
{
  gsl_dht *t = NULL;
  Data_Get_Struct(obj, gsl_dht, t);
  return INT2FIX(t->size);
}

static VALUE rb_gsl_dht_nu(VALUE obj)
{
  gsl_dht *t = NULL;
  Data_Get_Struct(obj, gsl_dht, t);
  return rb_float_new(t->nu);
}

static VALUE rb_gsl_dht_xmax(VALUE obj)
{
  gsl_dht *t = NULL;
  Data_Get_Struct(obj, gsl_dht, t);
  return rb_float_new(t->xmax);
}

static VALUE rb_gsl_dht_kmax(VALUE obj)
{
  gsl_dht *t = NULL;
  Data_Get_Struct(obj, gsl_dht, t);
  return rb_float_new(t->kmax);
}

static VALUE rb_gsl_dht_coef(int argc, VALUE *argv, VALUE obj)
{
  gsl_dht *t = NULL;
  gsl_matrix *mm = NULL;
  size_t n, m;
  double val;
  Data_Get_Struct(obj, gsl_dht, t);
  switch (argc) {
  case 0:
    mm = gsl_matrix_alloc(t->size, t->size);
    for (n = 0; n < t->size; n++) {
      for (m = 0; m < t->size; m++) {
	val = gsl_sf_bessel_Jnu(t->nu, t->j[n+1]*gsl_dht_x_sample(t, m)/t->xmax);
	val *= (2.0/t->xmax/t->xmax)/t->J2[m+1];
	gsl_matrix_set(mm, n, m, val);
      }
    }
    return Data_Wrap_Struct(cgsl_matrix, 0, gsl_matrix_free, mm);
    break;
  case 2:
    n = FIX2INT(argv[0]);
    m = FIX2INT(argv[1]);
    val = gsl_sf_bessel_Jnu(t->nu, t->j[n+1]*gsl_dht_x_sample(t, m)/t->xmax);
    val *= (2.0/t->xmax/t->xmax)/t->J2[m+1];
    return rb_float_new(val);
    break;
  default:
    rb_raise(rb_eArgError, "wrong number of arguments (%d for 0 or 2)", argc);
    break;
  }
  return Qnil;
}

void Init_gsl_dht(VALUE module)
{
  VALUE cgsl_dht;
  cgsl_dht = rb_define_class_under(module, "Dht", rb_cObject);
  rb_define_singleton_method(cgsl_dht, "alloc", rb_gsl_dht_alloc, 1);
  rb_define_singleton_method(cgsl_dht, "new", rb_gsl_dht_new, -1);
  rb_define_method(cgsl_dht, "init", rb_gsl_dht_init, 2);
  rb_define_method(cgsl_dht, "apply", rb_gsl_dht_apply, -1);
  rb_define_method(cgsl_dht, "x_sample", rb_gsl_dht_x_sample, 1);
  rb_define_method(cgsl_dht, "k_sample", rb_gsl_dht_k_sample, 1);

  rb_define_method(cgsl_dht, "size", rb_gsl_dht_size, 0);
  rb_define_method(cgsl_dht, "nu", rb_gsl_dht_nu, 0);
  rb_define_method(cgsl_dht, "xmax", rb_gsl_dht_xmax, 0);
  rb_define_method(cgsl_dht, "kmax", rb_gsl_dht_kmax, 0);

  rb_define_method(cgsl_dht, "j", rb_gsl_dht_j, 0);
  rb_define_method(cgsl_dht, "Jjj", rb_gsl_dht_Jjj, 0);
  rb_define_method(cgsl_dht, "J2", rb_gsl_dht_J2, 0);

  rb_define_method(cgsl_dht, "zero", rb_gsl_dht_zero, 0);
  rb_define_alias(cgsl_dht, "zeros", "zero");
  rb_define_method(cgsl_dht, "sample", rb_gsl_dht_sample, -1);
  rb_define_method(cgsl_dht, "num", rb_gsl_dht_num, -1);
  rb_define_method(cgsl_dht, "den", rb_gsl_dht_den, 0);
  rb_define_method(cgsl_dht, "coef", rb_gsl_dht_coef, -1);
}
