monitor.cpp

/* Copyright (C) 2005-2015 Massachusetts Institute of Technology
%
%  This program 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 program 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 program; if not, write to the Free Software Foundation,
%  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#include "meep.hpp"
#include "meep_internals.hpp"

#include "config.h"
#if defined(HAVE_LIBFFTW3)
#  include <fftw3.h>
#elif defined(HAVE_LIBDFFTW)
#  include <dfftw.h>
#elif defined(HAVE_LIBFFTW)
#  include <fftw.h>
#endif
#define HAVE_SOME_FFTW (defined(HAVE_LIBFFTW3) || defined(HAVE_LIBFFTW) || defined(HAVE_LIBDFFTW))

/* Below are the monitor point routines. */

using namespace std;

namespace meep {

monitor_point::monitor_point() {
  next = NULL;
}

monitor_point::~monitor_point() {
  if (next) delete next;
}

inline complex<double> getcm(const realnum * const f[2], int i) {
  return complex<double>(f[0][i],f[1][i]);
}

static void dumbsort(complex<double> val[8]) {
  for (int i=0;i<7;i++) {
    int lowest = i;
    for (int j=i+1;j<8;j++) if (abs(val[j]) < abs(val[lowest])) lowest = j;
    complex<double> tmp = val[i];
    val[i] = val[lowest];
    val[lowest] = tmp;
  }
}

static void dumbsort(double val[8]) {
  for (int i=0;i<7;i++) {
    int lowest = i;
    for (int j=i+1;j<8;j++) if (abs(val[j]) < abs(val[lowest])) lowest = j;
    double tmp = val[i];
    val[i] = val[lowest];
    val[lowest] = tmp;
  }
}

void fields::get_point(monitor_point *pt, const vec &loc) const {
  if (pt == NULL) abort("Error:  get_point passed a null pointer!\n");
  for (int i=0;i<10;i++) pt->f[i] = 0.0;
  pt->loc = loc;
  pt->t = time();
  FOR_COMPONENTS(c)
    if (gv.has_field(c))
      pt->f[c] = get_field(c,loc);
}

complex<double> fields::get_field(int c, const vec &loc) const {
  return (is_derived(c) ? get_field(derived_component(c), loc)
	  : get_field(component(c), loc));
}

double fields::get_field(derived_component c, const vec &loc) const {
  component c1 = Ex, c2 = Ex;
  double sum = 0;
  switch (c) {
  case Sx: case Sy: case Sz: case Sr: case Sp:
    switch (c) {
    case Sx: c1 = Ey; c2 = Hz; break;
    case Sy: c1 = Ez; c2 = Hx; break;
    case Sz: c1 = Ex; c2 = Hy; break;
    case Sr: c1 = Ep; c2 = Hz; break;
    case Sp: c1 = Ez; c2 = Hr; break;
    default: break; // never
    }
    sum += real(conj(get_field(c1, loc)) * get_field(c2, loc));
    sum -= real(conj(get_field(direction_component(Ex, component_direction(c2)), loc)) * get_field(direction_component(Hx, component_direction(c1)), loc));
    return sum;
  case EnergyDensity: case D_EnergyDensity: case H_EnergyDensity:
    if (c != H_EnergyDensity)
      FOR_ELECTRIC_COMPONENTS(c1) if (gv.has_field(c1)) {
	c2 = direction_component(Dx, component_direction(c1));
	sum += real(conj(get_field(c1, loc)) * get_field(c2, loc));
      }
    if (c != D_EnergyDensity)
      FOR_MAGNETIC_COMPONENTS(c1) if (gv.has_field(c1)) {
	complex<double> f = get_field(c1, loc);
	sum += real(conj(f) * f);
      }
    return sum * 0.5;
  default: abort("unknown derived_component in get_field");
  }
}

complex<double> fields::get_field(component c, const vec &loc) const {
  switch (c) {
  case Dielectric:
    return get_eps(loc);
  case Permeability:
    return get_mu(loc);
  default:
    ivec ilocs[8];
    double w[8];
    complex<double> val[8];
    for (int i=0;i<8;i++) val[i] = 0.0;
    gv.interpolate(c, loc, ilocs, w);
    for (int argh=0;argh<8&&w[argh];argh++)
      val[argh] = w[argh]*get_field(c,ilocs[argh]);
    dumbsort(val);
    complex<double> res = 0.0;
    for (int i=0;i<8;i++) res += val[i];
    return res;
  }
}

complex<double> fields::get_field(component c, const ivec &origloc) const {
  ivec iloc = origloc;
  complex<double> kphase = 1.0;
  locate_point_in_user_volume(&iloc, &kphase);
  for (int sn=0;sn<S.multiplicity();sn++)
    for (int i=0;i<num_chunks;i++)
      if (chunks[i]->gv.contains(S.transform(iloc,sn)))
        return S.phase_shift(c,sn)*kphase*
          chunks[i]->get_field(S.transform(c,sn),S.transform(iloc,sn));
  return 0.0;
}

complex<double> fields_chunk::get_field(component c, const ivec &iloc) const {
  complex<double> res = 0.0;
  if (f[c][0] && f[c][1]) res = getcm(f[c], gv.index(c, iloc));
  else if (f[c][0]) res = f[c][0][gv.index(c,iloc)];
  return broadcast(n_proc(), res);
}

/* Bounding box for zero-communication get_field, below.  This is the
   largest box in which you can interpolate the fields without communication.
   It is *not* necessarily non-overlapping with other chunks. */
volume fields_chunk::get_field_gv(component c) const {
  switch (c) {
  case Dielectric: case Permeability:
    c = gv.eps_component();
  default:
    return volume(gv.loc(c, 0), gv.loc(c, gv.ntot() - 1));
  }
}

/* Non-collective, zero-communication get_field... loc *must*
   be in get_field_gv(c). */
complex<double> fields_chunk::get_field(component c, const vec &loc) const {
  ivec ilocs[8];
  double w[8];
  switch (c) {
  case Permeability: abort("non-collective get_field(mu) unimplemented");
  case Dielectric: abort("non-collective get_field(eps) unimplemented");
  default: {
    gv.interpolate(c, loc, ilocs, w);
    complex<double> res = 0.0;
    for (int i = 0; i < 8 && w[i] != 0.0; ++i) {
      if (!gv.contains(ilocs[i]))
	abort("invalid loc in chunk get_field, weight = %g", w[i]);
      if (f[c][0] && f[c][1]) res += getcm(f[c], gv.index(c, ilocs[i])) * w[i];
      else if (f[c][0]) res += f[c][0][gv.index(c,ilocs[i])] * w[i];
    }
    return res;
  }
  }
}

double fields::get_chi1inv(component c, direction d,
			  const ivec &origloc) const {
  ivec iloc = origloc;
  complex<double> aaack = 1.0;
  locate_point_in_user_volume(&iloc, &aaack);
  for (int sn=0;sn<S.multiplicity();sn++)
    for (int i=0;i<num_chunks;i++)
      if (chunks[i]->gv.contains(S.transform(iloc,sn))) {
	signed_direction ds = S.transform(d,sn);
        return chunks[i]->get_chi1inv(S.transform(c,sn), ds.d,
				     S.transform(iloc,sn))
	     * (ds.flipped ^ S.transform(component_direction(c),sn).flipped
		? -1 : 1);
      }
  return 0.0;
}

double fields_chunk::get_chi1inv(component c, direction d,
			     const ivec &iloc) const {
  double res = 0.0;
  if (is_mine()) res = s->chi1inv[c][d] ? s->chi1inv[c][d][gv.index(c, iloc)]
		   : (d == component_direction(c) ? 1.0 : 0);
  return broadcast(n_proc(), res);
}

double fields::get_chi1inv(component c, direction d,
			  const vec &loc) const {
  ivec ilocs[8];
  double w[8];
  double val[8];
  for (int i=0;i<8;i++) val[i] = 0.0;
  gv.interpolate(c, loc, ilocs, w);
  for (int argh=0;argh<8&&w[argh];argh++)
    val[argh] = w[argh]*get_chi1inv(c,d,ilocs[argh]);
  dumbsort(val);
  double res = 0.0;
  for (int i=0;i<8;i++) res += val[i];
  return res;
}

double fields::get_eps(const vec &loc) const {
  double tr = 0;
  int nc = 0;
  FOR_ELECTRIC_COMPONENTS(c)
    if (gv.has_field(c)) {
      tr += get_chi1inv(c, component_direction(c), loc);
      ++nc;
    }
  return nc / tr;
}

double fields::get_mu(const vec &loc) const {
  double tr = 0;
  int nc = 0;
  FOR_MAGNETIC_COMPONENTS(c)
    if (gv.has_field(c)) {
      tr += get_chi1inv(c, component_direction(c), loc);
      ++nc;
    }
  return nc / tr;
}

double structure::get_chi1inv(component c, direction d,
			     const ivec &origloc) const {
  ivec iloc = origloc;
  for (int sn=0;sn<S.multiplicity();sn++)
    for (int i=0;i<num_chunks;i++)
      if (chunks[i]->gv.contains(S.transform(iloc,sn))) {
	signed_direction ds = S.transform(d,sn);
        return chunks[i]->get_chi1inv(S.transform(c,sn), ds.d,
				      S.transform(iloc,sn))
	  * (ds.flipped ^ S.transform(component_direction(c),sn).flipped
		? -1 : 1);
      }
  return 0.0;
}

double structure_chunk::get_chi1inv(component c, direction d,
				    const ivec &iloc) const {
  double res = 0.0;
  if (is_mine()) res = chi1inv[c][d] ? chi1inv[c][d][gv.index(c, iloc)] 
		   : (d == component_direction(c) ? 1.0 : 0);
  return broadcast(n_proc(), res);
}

double structure::get_chi1inv(component c, direction d,
			      const vec &loc) const {
  ivec ilocs[8];
  double w[8];
  double val[8];
  for (int i=0;i<8;i++) val[i] = 0.0;
  gv.interpolate(c, loc, ilocs, w);
  for (int argh=0;argh<8&&w[argh];argh++)
    val[argh] = w[argh]*get_chi1inv(c,d,ilocs[argh]);
  dumbsort(val);
  double res = 0.0;
  for (int i=0;i<8;i++) res += val[i];
  return res;
}

double structure::get_eps(const vec &loc) const {
  double tr = 0;
  int nc = 0;
  FOR_ELECTRIC_COMPONENTS(c)
    if (gv.has_field(c)) {
      tr += get_chi1inv(c, component_direction(c), loc);
      ++nc;
    }
  return nc / tr;
}

double structure::get_mu(const vec &loc) const {
  double tr = 0;
  int nc = 0;
  FOR_MAGNETIC_COMPONENTS(c)
    if (gv.has_field(c)) {
      tr += get_chi1inv(c, component_direction(c), loc);
      ++nc;
    }
  return nc / tr;
}

monitor_point *fields::get_new_point(const vec &loc, monitor_point *the_list) const {
  monitor_point *p = new monitor_point();
  get_point(p, loc);
  p->next = the_list;
  return p;
}

complex<double> monitor_point::get_component(component w) {
  return f[w];
}
  
double monitor_point::poynting_in_direction(direction d) {
  direction d1 = cycle_direction(loc.dim, d, 1);
  direction d2 = cycle_direction(loc.dim, d, 2);

  // below Ex and Hx are used just to say that we want electric or magnetic component
  complex<double> E1 = get_component(direction_component(Ex, d1));
  complex<double> E2 = get_component(direction_component(Ex, d2));
  complex<double> H1 = get_component(direction_component(Hx, d1));
  complex<double> H2 = get_component(direction_component(Hx, d2));

  return (real(E1)*real(H2) - real(E2)*real(H1)) + (imag(E1)*imag(H2) - imag(E2)*imag(H1));
}

double monitor_point::poynting_in_direction(vec dir) {
  if (dir.dim != loc.dim)
    abort("poynting_in_direction: dir.dim != loc.dim\n");
  dir = dir / abs(dir);
  double result = 0.0;
  LOOP_OVER_DIRECTIONS(dir.dim, d)
    result += dir.in_direction(d) * poynting_in_direction(d);
  return result;
}

void monitor_point::fourier_transform(component w,
                                      complex<double> **a, complex<double> **f,
                                      int *numout, double fmin, double fmax,
                                      int maxbands) {
  int n = 1;
  monitor_point *p = next;
  double tmax = t, tmin = t;
  while (p) {
    n++;
    if (p->t > tmax) tmax = p->t;
    if (p->t < tmin) tmin = p->t;
    p = p->next;
  }
  p = this;
  complex<double> *d = new complex<double>[n];
  for (int i=0;i<n;i++,p=p->next) {
    d[i] = p->get_component(w);
  }
  if (fmin > 0.0) { // Get rid of any static fields_chunk!
    complex<double> mean = 0.0;
    for (int i=0;i<n;i++) mean += d[i];
    mean /= n;
    for (int i=0;i<n;i++) d[i] -= mean;
  }
#if HAVE_SOME_FFTW
  if ((fmin > 0.0 || fmax > 0.0) && maxbands > 0) {
#else
  if ((fmin <= 0.0 && fmax <= 0.0) || maxbands <= 0) {
    maxbands = n;
    fmin = 0; fmax = (n-1)*(1.0/(tmax-tmin));
  }
#endif
    *a = new complex<double>[maxbands];
    *f = new complex<double>[maxbands];
    *numout = maxbands;
    delete[] d;
    for (int i = 0;i<maxbands;i++) {
      double df = (maxbands == 1) ? 0.0 : (fmax-fmin)/(maxbands-1);
      (*f)[i] = fmin + i*df;
      (*a)[i] = 0.0;
      p = this;
      while (p) {
        double inside = 2*pi*real((*f)[i])*p->t;
        (*a)[i] += p->get_component(w)*complex<double>(cos(inside),sin(inside));
        p = p->next;
      }
      (*a)[i] /= (tmax-tmin);
    }
#if HAVE_SOME_FFTW
  } else {
    *numout = n;
    *a = new complex<double>[n];
    *f = d;
    fftw_complex *in = (fftw_complex *) d, *out = (fftw_complex *) *a;
    fftw_plan p;
#ifdef HAVE_LIBFFTW3
    p = fftw_plan_dft_1d(n, in, out, FFTW_FORWARD, FFTW_ESTIMATE);
    fftw_execute(p);
    fftw_destroy_plan(p);
#else
    p = fftw_create_plan(n, FFTW_FORWARD, FFTW_ESTIMATE);
    fftw_one(p, in, out);
    fftw_destroy_plan(p);
#endif
    for (int i=0;i<n;i++) {
      (*f)[i] = i*(1.0/(tmax-tmin));
      if (real((*f)[i]) > 0.5*n/(tmax-tmin)) (*f)[i] -= n/(tmax-tmin);
      (*a)[i] *= (tmax-tmin)/n;
    }
  }
#endif
}

void monitor_point::harminv(component w,
                            complex<double> **a, complex<double> **f,
                            int *numout, double fmin, double fmax,
                            int maxbands) {
  int n = 1;
  monitor_point *p = next;
  double tmax = t, tmin = t;
  while (p) {
    n++;
    if (p->t > tmax) tmax = p->t;
    if (p->t < tmin) tmin = p->t;
    p = p->next;
  }
  p = this;
  complex<double> *d = new complex<double>[n];
  for (int i=0;i<n;i++,p=p->next) {
    d[i] = p->get_component(w);
  }
  *a = new complex<double>[n];
  double *f_re = new double[n];
  double *f_im = new double[n];
  *numout = do_harminv(d, n, (tmax-tmin)/(n-1), fmin, fmax, maxbands,
                       *a, f_re, f_im, NULL);
  *f = new complex<double>[*numout];
  for (int i=0;i<*numout;i++)
    (*f)[i] = complex<double>(f_re[i],f_im[i]);
  delete[] f_re;
  delete[] f_im;
  delete[] d;
}

} // namespace meep