/*
 * iexp.cpp - exponential current source class implementation
 *
 * Copyright (C) 2007, 2008 Stefan Jahn <stefan@lkcc.org>
 * Copyright (C) 2007 Gunther Kraut <gn.kraut@t-online.de>
 *
 * This is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this package; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 * $Id$
 *
 */

#if HAVE_CONFIG_H
# include <config.h>
#endif

#include "component.h"
#include "iexp.h"

using namespace qucs;

iexp::iexp () : circuit (2) {
  type = CIR_IEXP;
  setISource (true);
}

void iexp::initSP (void) {
  allocMatrixS ();
  setS (NODE_1, NODE_1, 1.0);
  setS (NODE_1, NODE_2, 0.0);
  setS (NODE_2, NODE_1, 0.0);
  setS (NODE_2, NODE_2, 1.0);
}

void iexp::initDC (void) {
  nr_double_t i = getPropertyDouble ("I1");
  allocMatrixMNA ();
  setI (NODE_1, +i); setI (NODE_2, -i);
}

void iexp::initAC (void) {
  allocMatrixMNA ();
  clearI ();
}

void iexp::initTR (void) {
  initDC ();
}

void iexp::calcTR (nr_double_t t) {
  nr_double_t i1 = getPropertyDouble ("I1");
  nr_double_t i2 = getPropertyDouble ("I2");
  nr_double_t t1 = getPropertyDouble ("T1");
  nr_double_t t2 = getPropertyDouble ("T2");
  nr_double_t tr = getPropertyDouble ("Tr");
  nr_double_t tf = getPropertyDouble ("Tf");
  nr_double_t it = 0;
  nr_double_t s  = getNet()->getSrcFactor ();

  if (t <= t1) { // before pulse
    it = i1;
  }
  else if (t > t1 && t <= t2) { // rising edge
    it = i1 + (i2 - i1) * (1 - std::exp (-(t - t1) / tr));
  }
  else { // falling edge
    it += i1;
    it += (i2 - i1) * (1 - std::exp (-(t - t1) / tr));
    it -= (i2 - i1) * (1 - std::exp (-(t - t2) / tf));
  }
  setI (NODE_1, +it * s); setI (NODE_2, -it * s);
}

// properties
PROP_REQ [] = {
  { "I1", PROP_REAL, { 0, PROP_NO_STR }, PROP_NO_RANGE },
  { "I2", PROP_REAL, { 1, PROP_NO_STR }, PROP_NO_RANGE },
  { "T1", PROP_REAL, { 0, PROP_NO_STR }, PROP_POS_RANGE },
  { "T2", PROP_REAL, { 1e-3, PROP_NO_STR }, PROP_POS_RANGE },
  PROP_NO_PROP };
PROP_OPT [] = {
  { "Tr", PROP_REAL, { 1e-9, PROP_NO_STR }, PROP_POS_RANGE },
  { "Tf", PROP_REAL, { 1e-9, PROP_NO_STR }, PROP_POS_RANGE },
  PROP_NO_PROP };
struct define_t iexp::cirdef =
  { "Iexp", 2, PROP_COMPONENT, PROP_NO_SUBSTRATE, PROP_LINEAR, PROP_DEF };