int
main( int argc, char **argv )
{
  int arg;                      /* command-line argument counter */
  BOOLEAN xyz = 0;              /* whether -x, -y, or -z options were given */
  INT4 verbosity = 0;           /* verbosity level */
  REAL8 x_1 = 0.0, x_2 = 0.0, dx; /* range and increment in x */
  REAL8 y_1 = 0.0, y_2 = 0.0, dy; /* range and increment in y */
  REAL8 z_1 = 0.0, z_2 = 0.0, dz; /* range and increment in z */
  INT4 nx = 1, ny = 1, nz = 1;  /* number of steps in each direction */
  INT4 i, j, k;                 /* index in each direction */
  REAL8 x, y, z, ddx, ddy, ddz; /* position and error in each direction */
  REAL8 ddr, ddmax = 0.0;       /* overall and maximum position error */
  static LALStatus stat;        /* status structure */
  EarthPosition earth;          /* terrestrial coordinates */


  /*******************************************************************
   * PARSE ARGUMENTS (arg stores the current position)               *
   *******************************************************************/

  arg = 1;
  while ( arg < argc ) {

    /* Parse range options. */
    if ( !strcmp( argv[arg], "-x" ) ) {
      if ( argc > arg + 3 ) {
	arg++;
	xyz = 1;
	x_1 = atof( argv[arg++] );
	x_2 = atof( argv[arg++] );
	nx = atoi( argv[arg++] );
      } else {
	ERROR( GEOCENTRICGEODETICTESTC_EARG,
	       GEOCENTRICGEODETICTESTC_MSGEARG, 0 );
        LALPrintError( USAGE, *argv );
        return GEOCENTRICGEODETICTESTC_EARG;
      }
    } else if ( !strcmp( argv[arg], "-y" ) ) {
      if ( argc > arg + 3 ) {
	arg++;
	xyz = 1;
	y_1 = atof( argv[arg++] );
	y_2 = atof( argv[arg++] );
	ny = atoi( argv[arg++] );
      } else {
	ERROR( GEOCENTRICGEODETICTESTC_EARG,
	       GEOCENTRICGEODETICTESTC_MSGEARG, 0 );
        LALPrintError( USAGE, *argv );
        return GEOCENTRICGEODETICTESTC_EARG;
      }
    } else if ( !strcmp( argv[arg], "-z" ) ) {
      if ( argc > arg + 3 ) {
	arg++;
	xyz = 1;
	z_1 = atof( argv[arg++] );
	z_2 = atof( argv[arg++] );
	nz = atoi( argv[arg++] );
      } else {
	ERROR( GEOCENTRICGEODETICTESTC_EARG,
	       GEOCENTRICGEODETICTESTC_MSGEARG, 0 );
        LALPrintError( USAGE, *argv );
        return GEOCENTRICGEODETICTESTC_EARG;
      }
    }

    /* Parse verbosity option. */
    else if ( !strcmp( argv[arg], "-v" ) ) {
      if ( argc > arg + 1 ) {
	arg++;
	verbosity = atoi( argv[arg++] );
      } else {
	ERROR( GEOCENTRICGEODETICTESTC_EARG,
	       GEOCENTRICGEODETICTESTC_MSGEARG, 0 );
        LALPrintError( USAGE, *argv );
        return GEOCENTRICGEODETICTESTC_EARG;
      }
    }

    /* Parse debug level option. */
    else if ( !strcmp( argv[arg], "-d" ) ) {
      if ( argc > arg + 1 ) {
	arg++;
      } else {
	ERROR( GEOCENTRICGEODETICTESTC_EARG,
	       GEOCENTRICGEODETICTESTC_MSGEARG, 0 );
        LALPrintError( USAGE, *argv );
        return GEOCENTRICGEODETICTESTC_EARG;
      }
    }

    /* Check for unrecognized options. */
    else if ( argv[arg][0] == '-' ) {
      ERROR( GEOCENTRICGEODETICTESTC_EARG,
	     GEOCENTRICGEODETICTESTC_MSGEARG, 0 );
      LALPrintError( USAGE, *argv );
      return GEOCENTRICGEODETICTESTC_EARG;
    }
  } /* End of argument parsing loop. */

  /*******************************************************************
   * SET PARAMETERS                                                  *
   *******************************************************************/

  /* If none of -x, -y, -z were given, generate a random position. */
  if ( !xyz ) {
    REAL4 lon, coslat, sinlat, rad; /* polar coordinates */
    RandomParams *rparams = NULL;   /* pseudorandom sequence parameters */
    SUB( LALCreateRandomParams( &stat, &rparams, 0 ), &stat );
    SUB( LALUniformDeviate( &stat, &lon, rparams ), &stat );
    lon *= LAL_TWOPI;
    SUB( LALUniformDeviate( &stat, &sinlat, rparams ), &stat );
    coslat = sqrt( 1.0 - sinlat*sinlat );
    SUB( LALUniformDeviate( &stat, &rad, rparams ), &stat );
    rad = 1.5*rad + 0.5;
    x_1 = x_2 = rad*coslat*cos( lon );
    y_1 = y_2 = rad*coslat*sin( lon );
    z_1 = z_2 = rad*sinlat;
    SUB( LALDestroyRandomParams( &stat, &rparams ), &stat );
  }

  /* Compute stepsizes. */
  dx = dy = dz = 0.0;
  if ( nx > 1 )
    dx = ( x_2 - x_1 )/( nx - 1.0 );
  if ( ny > 1 )
    dy = ( y_2 - y_1 )/( ny - 1.0 );
  if ( nz > 1 )
    dz = ( z_2 - z_1 )/( nz - 1.0 );

  /*******************************************************************
   * PERFORM TEST                                                    *
   *******************************************************************/

  /* Loop over each direction. */
  for ( i = 0; i < nx; i++ ) {
    x = LAL_REARTH_SI*( x_1 + i*dx );
    for ( j = 0; j < ny; j++ ) {
      y = LAL_REARTH_SI*( y_1 + j*dy );
      for ( k = 0; k < nz; k++ ) {
	z = LAL_REARTH_SI*( z_1 + k*dz );

	/* Do transformation. */
	earth.x = x;
	earth.y = y;
	earth.z = z;
	SUB( LALGeocentricToGeodetic( &stat, &earth ), &stat );
 	SUB( LALGeodeticToGeocentric( &stat, &earth ), &stat );

	/* Compute difference. */
	ddx = x - earth.x;
	ddy = y - earth.y;
	ddz = z - earth.z;
	ddr = sqrt( ddx*ddx + ddy*ddy + ddz*ddz );
	if ( ddr > ddmax )
	  ddmax = ddr;
	if ( verbosity == 1 )
	  fprintf( stdout, "%+23.16e\n", ddr );
	else if ( verbosity == 2 )
	  fprintf( stdout, "%+23.16e %+23.16e\n", earth.elevation, ddr );
	else if ( verbosity == 3 )
	  fprintf( stdout, "%+23.16e %+23.16e %+23.16e %+23.16e\n",
		   x, y, z, ddr );
	else if ( verbosity == 4 )
	  fprintf( stdout, "%+23.16e %+23.16e %+23.16e"
		   " %+23.16e %+23.16e %+23.16e %+23.16e\n", x, y, z,
		   earth.elevation, LAL_180_PI*earth.geodetic.latitude,
		   LAL_180_PI*earth.geodetic.longitude, ddr );
      }
    }
  }

  /* Print maximum. */
  fprintf( stdout, "Maximum error: %.16em\n", ddmax );
  if ( !xyz && ddmax > 1.0e-6 ) {
    ERROR( GEOCENTRICGEODETICTESTC_ETEST,
	   GEOCENTRICGEODETICTESTC_MSGETEST, 0 );
    return GEOCENTRICGEODETICTESTC_ETEST;
  }
  LALCheckMemoryLeaks();
  INFO( GEOCENTRICGEODETICTESTC_MSGENORM );
  return GEOCENTRICGEODETICTESTC_ENORM;
}
/**
 * \author Creighton, T. D.
 *
 * \brief Computes the response of a detector to a coherent gravitational wave.
 *
 * This function takes a quasiperiodic gravitational waveform given in
 * <tt>*signal</tt>, and estimates the corresponding response of the
 * detector whose position, orientation, and transfer function are
 * specified in <tt>*detector</tt>.  The result is stored in
 * <tt>*output</tt>.
 *
 * The fields <tt>output-\>epoch</tt>, <tt>output->deltaT</tt>, and
 * <tt>output-\>data</tt> must already be set, in order to specify the time
 * period and sampling rate for which the response is required.  If
 * <tt>output-\>f0</tt> is nonzero, idealized heterodyning is performed (an
 * amount \f$2\pi f_0(t-t_0)\f$ is subtracted from the phase before computing
 * the sinusoid, where \f$t_0\f$ is the heterodyning epoch defined in
 * \c detector).  For the input signal, <tt>signal-\>h</tt> is ignored,
 * and the signal is treated as zero at any time for which either
 * <tt>signal-\>a</tt> or <tt>signal-\>phi</tt> is not defined.
 *
 * This routine will convert <tt>signal-\>position</tt> to equatorial
 * coordinates, if necessary.
 *
 * ### Algorithm ###
 *
 * The routine first accounts for the time delay between the detector and
 * the solar system barycentre, based on the detector position
 * information stored in <tt>*detector</tt> and the propagation direction
 * specified in <tt>*signal</tt>.  Values of the propagation delay are
 * precomuted at fixed intervals and stored in a table, with the
 * intervals \f$\Delta T_\mathrm{delay}\f$ chosen such that the value
 * interpolated from adjacent table entries will never differ from the
 * true value by more than some timing error \f$\sigma_T\f$.  This implies
 * that:
 * \f[
 * \Delta T_\mathrm{delay} \leq \sqrt{
 * \frac{8\sigma_T}{\max\{a/c\}} } \; ,
 * \f]
 * where \f$\max\{a/c\}=1.32\times10^{-10}\mathrm{s}^{-1}\f$ is the maximum
 * acceleration of an Earth-based detector in the barycentric frame.  The
 * total propagation delay also includes Einstein and Shapiro delay, but
 * these are more slowly varying and thus do not constrain the table
 * spacing.  At present, a 400s table spacing is hardwired into the code,
 * implying \f$\sigma_T\approx3\mu\f$s, comparable to the stated accuracy of
 * <tt>LALBarycenter()</tt>.
 *
 * Next, the polarization response functions of the detector
 * \f$F_{+,\times}(\alpha,\delta)\f$ are computed for every 10 minutes of the
 * signal's duration, using the position of the source in <tt>*signal</tt>,
 * the detector information in <tt>*detector</tt>, and the function
 * <tt>LALComputeDetAMResponseSeries()</tt>.  Subsequently, the
 * polarization functions are estimated for each output sample by
 * interpolating these precomputed values.  This guarantees that the
 * interpolated value is accurate to \f$\sim0.1\%\f$.
 *
 * Next, the frequency response of the detector is estimated in the
 * quasiperiodic limit as follows:
 * <ul>
 * <li> At each sample point in <tt>*output</tt>, the propagation delay is
 * computed and added to the sample time, and the instantaneous
 * amplitudes \f$A_1\f$, \f$A_2\f$, frequency \f$f\f$, phase \f$\phi\f$, and polarization
 * shift \f$\Phi\f$ are found by interpolating the nearest values in
 * <tt>signal-\>a</tt>, <tt>signal-\>f</tt>, <tt>signal-\>phi</tt>, and
 * <tt>signal-\>shift</tt>, respectively.  If <tt>signal-\>f</tt> is not
 * defined at that point in time, then \f$f\f$ is estimated by differencing
 * the two nearest values of \f$\phi\f$, as \f$f\approx\Delta\phi/2\pi\Delta
 * t\f$.  If <tt>signal-\>shift</tt> is not defined, then \f$\Phi\f$ is treated as
 * zero.</li>
 * <li> The complex transfer function of the detector the frequency \f$f\f$
 * is found by interpolating <tt>detector-\>transfer</tt>.  The amplitude of
 * the transfer function is multiplied with \f$A_1\f$ and \f$A_2\f$, and the
 * phase of the transfer function is added to \f$\phi\f$,</li>
 * <li> The plus and cross contributions \f$o_+\f$, \f$o_\times\f$ to the
 * detector output are computed as in \eqref{eq_quasiperiodic_hpluscross}
 * of \ref PulsarSimulateCoherentGW_h, but
 * using the response-adjusted amplitudes and phase.</li>
 * <li> The final detector response \f$o\f$ is computed as
 * \f$o=(o_+F_+)+(o_\times F_\times)\f$.</li>
 * </ul>
 *
 * ### A note on interpolation: ###
 *
 * Much of the computational work in this routine involves interpolating
 * various time series to find their values at specific output times.
 * The algorithm is summarized below.
 *
 * Let \f$A_j = A( t_A + j\Delta t_A )\f$ be a sampled time series, which we
 * want to resample at new (output) time intervals \f$t_k = t_0 + k\Delta
 * t\f$.  We first precompute the following quantities:
 * \f{eqnarray}{
 * t_\mathrm{off} & = & \frac{t_0-t_A}{\Delta t_A}  \; , \\
 * dt & = & \frac{\Delta t}{\Delta t_A} \; .
 * \f}
 * Then, for each output sample time \f$t_k\f$, we compute:
 * \f{eqnarray}{
 * t & = & t_\mathrm{off} + k \times dt \; , \\
 * j & = & \lfloor t \rfloor            \; , \\
 * f & = & t - j                        \; ,
 * \f}
 * where \f$\lfloor x\rfloor\f$ is the "floor" function; i.e.\ the largest
 * integer \f$\leq x\f$.  The time series sampled at the new time is then:
 * \f[
 * A(t_k) = f \times A_{j+1} + (1-f) \times A_j \; .
 * \f]
 *
 * ### Notes ###
 *
 * The major computational hit in this routine comes from computing the
 * sine and cosine of the phase angle in
 * \eqref{eq_quasiperiodic_hpluscross} of
 * \ref PulsarSimulateCoherentGW_h.  For better online performance, these can
 * be replaced by other (approximate) trig functions.  Presently the code
 * uses the native \c libm functions by default, or the function
 * <tt>sincosp()</tt> in \c libsunmath \e if this function is
 * available \e and the constant \c ONLINE is defined.
 * Differences at the level of 0.01 begin to appear only for phase
 * arguments greater than \f$10^{14}\f$ or so (corresponding to over 500
 * years between phase epoch and observation time for frequencies of
 * around 1kHz).
 *
 * To activate this feature, be sure that <tt>sunmath.h</tt> and
 * \c libsunmath are on your system, and add <tt>-DONLINE</tt> to the
 * <tt>--with-extra-cppflags</tt> configuration argument.  In future this
 * flag may be used to turn on other efficient trig algorithms on other
 * (non-Solaris) platforms.
 *
 */
void
LALPulsarSimulateCoherentGW( LALStatus        *stat,
                       REAL4TimeSeries  *output,
                       PulsarCoherentGW       *CWsignal,
                       PulsarDetectorResponse *detector )
{
  INT4 i, n;          /* index over output->data, and its final value */
  INT4 nMax;          /* used to store limits on index ranges */
  INT4 fInit, fFinal; /* index range for which CWsignal->f is defined */
  INT4 shiftInit, shiftFinal; /* ditto for CWsignal->shift */
  UINT4 dtDelayBy2;     /* delay table half-interval (s) */
  UINT4 dtPolBy2;       /* polarization table half-interval (s) */
  REAL4 *outData;             /* pointer to output data */
  REAL8 delayMin, delayMax;   /* min and max values of time delay */
  SkyPosition source;         /* source sky position */
  BOOLEAN transfer;  /* 1 if transfer function is specified */
  BOOLEAN fFlag = 0; /* 1 if frequency left detector->transfer range */
  BOOLEAN pFlag = 0; /* 1 if frequency was estimated from phase */

  /* get delay table and polaristion tables half intervals if defined (>0) in
     the PulsarCoherentGW structure otherwise default to 400s for dtDelatBy2 and 300s
     for dtPolBy2 */
  dtDelayBy2 = CWsignal->dtDelayBy2 > 0 ? CWsignal->dtDelayBy2 : 400;
  dtPolBy2   = CWsignal->dtPolBy2   > 0 ? CWsignal->dtPolBy2   : 300;

  /* The amplitude, frequency, phase, polarization shift, polarization
     response, and propagation delay are stored in arrays that must be
     interpolated.  For a quantity x, we define a pointer xData to the
     data array.  At some time t measured in units of output->deltaT,
     the interpolation point in xData is given by ( xOff + t*xDt ),
     where xOff is an offset and xDt is a relative sampling rate. */
  LALDetAMResponseSeries polResponse;
  REAL8Vector *delay = NULL;
  REAL4 *aData, *fData, *shiftData, *plusData, *crossData;
  REAL8 *phiData, *delayData;
  REAL8 aOff, fOff, phiOff, shiftOff, polOff, delayOff;
  REAL8 aDt, fDt, phiDt, shiftDt, polDt, delayDt;

  /* Frequencies in the detector transfer function are interpolated
     similarly, except everything is normalized with respect to
     detector->transfer->deltaF. */
  REAL4Vector *aTransfer = NULL;
  REAL4Vector *phiTransfer = NULL;
  REAL4Vector *phiTemp = NULL;
  REAL4 *aTransData = NULL, *phiTransData = NULL;
  REAL8 f0 = 1.0;
  REAL8 phiFac = 1.0, fFac = 1.0;

  /* Heterodyning phase factor LAL_TWOPI*output->f0*output->deltaT,
     and phase offset at the start of the series
     LAL_TWOPI*output->f0*(time offset). */
  REAL8 heteroFac, phi0;

  /* Variables required by the TCENTRE() macro, above. */
  REAL8 realIndex;
  INT4 intIndex;
  REAL8 indexFrac;

  INITSTATUS(stat);
  ATTATCHSTATUSPTR( stat );

  /* Make sure parameter structures and their fields exist. */
  ASSERT( CWsignal, stat, SIMULATECOHERENTGWH_ENUL,
          SIMULATECOHERENTGWH_MSGENUL );
  if ( !( CWsignal->a ) ) {
    ABORT( stat, SIMULATECOHERENTGWH_ESIG,
           SIMULATECOHERENTGWH_MSGESIG );
  }
  ASSERT( CWsignal->a->data, stat,
          SIMULATECOHERENTGWH_ENUL, SIMULATECOHERENTGWH_MSGENUL );
  ASSERT( CWsignal->a->data->data, stat,
          SIMULATECOHERENTGWH_ENUL, SIMULATECOHERENTGWH_MSGENUL );
  if ( !( CWsignal->phi ) ) {
    ABORT( stat, SIMULATECOHERENTGWH_ESIG,
           SIMULATECOHERENTGWH_MSGESIG );
  }
  ASSERT( CWsignal->phi->data, stat,
          SIMULATECOHERENTGWH_ENUL, SIMULATECOHERENTGWH_MSGENUL );
  ASSERT( CWsignal->phi->data->data, stat,
          SIMULATECOHERENTGWH_ENUL, SIMULATECOHERENTGWH_MSGENUL );
  if ( CWsignal->f ) {
    ASSERT( CWsignal->f->data, stat,
            SIMULATECOHERENTGWH_ENUL, SIMULATECOHERENTGWH_MSGENUL );
    ASSERT( CWsignal->f->data->data, stat,
            SIMULATECOHERENTGWH_ENUL, SIMULATECOHERENTGWH_MSGENUL );
  }
  if ( CWsignal->shift ) {
    ASSERT( CWsignal->shift->data, stat,
            SIMULATECOHERENTGWH_ENUL, SIMULATECOHERENTGWH_MSGENUL );
    ASSERT( CWsignal->shift->data->data, stat,
            SIMULATECOHERENTGWH_ENUL, SIMULATECOHERENTGWH_MSGENUL );
  }
  ASSERT( detector, stat,
          SIMULATECOHERENTGWH_ENUL, SIMULATECOHERENTGWH_MSGENUL );
  if ( ( transfer = ( detector->transfer != NULL ) ) ) {
    ASSERT( detector->transfer->data, stat,
            SIMULATECOHERENTGWH_ENUL, SIMULATECOHERENTGWH_MSGENUL );
    ASSERT( detector->transfer->data->data, stat,
            SIMULATECOHERENTGWH_ENUL, SIMULATECOHERENTGWH_MSGENUL );
  }
  ASSERT( output, stat,
          SIMULATECOHERENTGWH_ENUL, SIMULATECOHERENTGWH_MSGENUL );
  ASSERT( output->data, stat,
          SIMULATECOHERENTGWH_ENUL, SIMULATECOHERENTGWH_MSGENUL );
  ASSERT( output->data->data, stat,
          SIMULATECOHERENTGWH_ENUL, SIMULATECOHERENTGWH_MSGENUL );

  /* Check dimensions of amplitude array. */
  ASSERT( CWsignal->a->data->vectorLength == 2, stat,
          SIMULATECOHERENTGWH_EDIM, SIMULATECOHERENTGWH_MSGEDIM );

  /* Make sure we never divide by zero. */
  ASSERT( CWsignal->a->deltaT != 0.0, stat,
          SIMULATECOHERENTGWH_EBAD, SIMULATECOHERENTGWH_MSGEBAD );
  ASSERT( CWsignal->phi->deltaT != 0.0, stat,
          SIMULATECOHERENTGWH_EBAD, SIMULATECOHERENTGWH_MSGEBAD );
  aDt = output->deltaT / CWsignal->a->deltaT;
  phiDt = output->deltaT / CWsignal->phi->deltaT;
  ASSERT( aDt != 0.0, stat,
          SIMULATECOHERENTGWH_EBAD, SIMULATECOHERENTGWH_MSGEBAD );
  ASSERT( phiDt != 0.0, stat,
          SIMULATECOHERENTGWH_EBAD, SIMULATECOHERENTGWH_MSGEBAD );
  if ( CWsignal->f ) {
    ASSERT( CWsignal->f->deltaT != 0.0, stat,
            SIMULATECOHERENTGWH_EBAD, SIMULATECOHERENTGWH_MSGEBAD );
    fDt = output->deltaT / CWsignal->f->deltaT;
    ASSERT( fDt != 0.0, stat,
            SIMULATECOHERENTGWH_EBAD, SIMULATECOHERENTGWH_MSGEBAD );
  } else
    fDt = 0.0;
  if ( CWsignal->shift ) {
    ASSERT( CWsignal->shift->deltaT != 0.0, stat,
            SIMULATECOHERENTGWH_EBAD, SIMULATECOHERENTGWH_MSGEBAD );
    shiftDt = output->deltaT / CWsignal->shift->deltaT;
    ASSERT( shiftDt != 0.0, stat,
            SIMULATECOHERENTGWH_EBAD, SIMULATECOHERENTGWH_MSGEBAD );
  } else
    shiftDt = 0.0;
  if ( transfer ) {
    ASSERT( detector->transfer->deltaF != 0.0, stat,
            SIMULATECOHERENTGWH_EBAD, SIMULATECOHERENTGWH_MSGEBAD );
    fFac = 1.0 / detector->transfer->deltaF;
    phiFac = fFac / ( LAL_TWOPI*CWsignal->phi->deltaT );
    f0 = detector->transfer->f0/detector->transfer->deltaF;
  }
  heteroFac = LAL_TWOPI*output->f0*output->deltaT;
  phi0 = (REAL8)( output->epoch.gpsSeconds -
                  detector->heterodyneEpoch.gpsSeconds );
  phi0 += 0.000000001*(REAL8)( output->epoch.gpsNanoSeconds -
                               detector->heterodyneEpoch.gpsNanoSeconds );
  phi0 *= LAL_TWOPI*output->f0;
  if ( phi0 > 1.0/LAL_REAL8_EPS ) {
    LALWarning( stat, "REAL8 arithmetic is not sufficient to maintain"
                " heterodyne phase to within a radian." );
  }

  /* Check units on input, and set units on output. */
  {
    ASSERT( XLALUnitCompare( &(CWsignal->f->sampleUnits), &lalHertzUnit ) == 0, stat, SIMULATECOHERENTGWH_EUNIT, SIMULATECOHERENTGWH_MSGEUNIT );
    ASSERT( XLALUnitCompare( &(CWsignal->phi->sampleUnits), &lalDimensionlessUnit ) == 0, stat, SIMULATECOHERENTGWH_EUNIT, SIMULATECOHERENTGWH_MSGEUNIT );
    if( CWsignal->shift ) {
      ASSERT( XLALUnitCompare( &(CWsignal->shift->sampleUnits), &lalDimensionlessUnit ) == 0, stat, SIMULATECOHERENTGWH_EUNIT, SIMULATECOHERENTGWH_MSGEUNIT );
    }
    if ( transfer ) {
      if ( XLALUnitMultiply( &(output->sampleUnits), &(CWsignal->a->sampleUnits), &(detector->transfer->sampleUnits) ) == NULL ) {
        ABORT( stat, SIMULATECOHERENTGWH_EUNIT, SIMULATECOHERENTGWH_MSGEUNIT );
      }
    } else {
      output->sampleUnits = CWsignal->a->sampleUnits;
    }
    snprintf( output->name, LALNameLength, "response to %s", CWsignal->a->name );
  }

  /* Define temporary variables to access the data of CWsignal->a,
     CWsignal->f, and CWsignal->phi. */
  aData = CWsignal->a->data->data;
  INT4 aLen = CWsignal->a->data->length * CWsignal->a->data->vectorLength;
  phiData = CWsignal->phi->data->data;
  INT4 phiLen = CWsignal->phi->data->length;
  outData = output->data->data;
  INT4 fLen=0, shiftLen=0;
  if ( CWsignal->f )
    {
      fData = CWsignal->f->data->data;
      fLen = CWsignal->f->data->length;
    }
  else
    {
      fData = NULL;
    }

  if ( CWsignal->shift )
    {
      shiftData = CWsignal->shift->data->data;
      shiftLen = CWsignal->shift->data->length;
    }
  else
    {
      shiftData = NULL;
    }

  /* Convert source position to equatorial coordinates, if
     required. */
  if ( detector->site ) {
    source = CWsignal->position;
    if ( source.system != COORDINATESYSTEM_EQUATORIAL ) {
      ConvertSkyParams params; /* parameters for conversion */
      EarthPosition location;  /* location of detector */
      params.gpsTime = &( output->epoch );
      params.system = COORDINATESYSTEM_EQUATORIAL;
      if ( source.system == COORDINATESYSTEM_HORIZON ) {
        params.zenith = &( location.geodetic );
        location.x = detector->site->location[0];
        location.y = detector->site->location[1];
        location.z = detector->site->location[2];
        TRY( LALGeocentricToGeodetic( stat->statusPtr, &location ),
             stat );
      }
      TRY( LALConvertSkyCoordinates( stat->statusPtr, &source,
                                     &source, &params ), stat );
    }
  }

  /* Generate the table of propagation delays.
     dtDelayBy2 = (UINT4)( 38924.9/sqrt( output->f0 +
     1.0/output->deltaT ) ); */
  delayDt = output->deltaT/( 2.0*dtDelayBy2 );
  nMax = (UINT4)( output->data->length*delayDt ) + 3;
  TRY( LALDCreateVector( stat->statusPtr, &delay, nMax ), stat );
  delayData = delay->data;

  /* Compute delay from solar system barycentre. */
  if ( detector->site && detector->ephemerides ) {
    LIGOTimeGPS gpsTime;   /* detector time when we compute delay */
    EarthState state;      /* Earth position info at that time */
    BarycenterInput input; /* input structure to LALBarycenter() */
    EmissionTime emit;     /* output structure from LALBarycenter() */

    /* Arrange nested pointers, and set initial values. */
    gpsTime = input.tgps = output->epoch;
    gpsTime.gpsSeconds -= dtDelayBy2;
    input.tgps.gpsSeconds -= dtDelayBy2;
    input.site = *(detector->site);
    for ( i = 0; i < 3; i++ )
      input.site.location[i] /= LAL_C_SI;
    input.alpha = source.longitude;
    input.delta = source.latitude;
    input.dInv = 0.0;
    delayMin = delayMax = 1.1*LAL_AU_SI/( LAL_C_SI*output->deltaT );
    delayMax *= -1;

    /* Compute table. */
    for ( i = 0; i < nMax; i++ ) {
      REAL8 tDelay; /* propagation time */
      LALBarycenterEarth( stat->statusPtr, &state, &gpsTime,
                          detector->ephemerides );
      BEGINFAIL( stat )
        TRY( LALDDestroyVector( stat->statusPtr, &delay ), stat );
      ENDFAIL( stat );
      LALBarycenter( stat->statusPtr, &emit, &input, &state );
      BEGINFAIL( stat )
        TRY( LALDDestroyVector( stat->statusPtr, &delay ), stat );
      ENDFAIL( stat );
      delayData[i] = tDelay = emit.deltaT/output->deltaT;
      if ( tDelay < delayMin )
        delayMin = tDelay;
      if ( tDelay > delayMax )
        delayMax = tDelay;
      gpsTime.gpsSeconds += 2*dtDelayBy2;
      input.tgps.gpsSeconds += 2*dtDelayBy2;
    }
  }

  /* No information from which to compute delays. */
  else {
    LALInfo( stat, "Detector site and ephemerides absent; simulating hplus with no"
             " propagation delays" );
    memset( delayData, 0, nMax*sizeof(REAL8) );
    delayMin = delayMax = 0.0;
  }

  /* Generate the table of polarization response functions. */
  polDt = output->deltaT/( 2.0*dtPolBy2 );
  nMax = (UINT4)( output->data->length*polDt ) + 3;
  memset( &polResponse, 0, sizeof( LALDetAMResponseSeries ) );
  polResponse.pPlus = (REAL4TimeSeries *)
    LALMalloc( sizeof(REAL4TimeSeries) );
  polResponse.pCross = (REAL4TimeSeries *)
    LALMalloc( sizeof(REAL4TimeSeries) );
  polResponse.pScalar = (REAL4TimeSeries *)
    LALMalloc( sizeof(REAL4TimeSeries) );
  if ( !polResponse.pPlus || !polResponse.pCross ||
       !polResponse.pScalar ) {
    if ( polResponse.pPlus )
      LALFree( polResponse.pPlus );
    if ( polResponse.pCross )
      LALFree( polResponse.pCross );
    if ( polResponse.pScalar )
      LALFree( polResponse.pScalar );
    TRY( LALDDestroyVector( stat->statusPtr, &delay ), stat );
    ABORT( stat, SIMULATECOHERENTGWH_EMEM,
           SIMULATECOHERENTGWH_MSGEMEM );
  }
  memset( polResponse.pPlus, 0, sizeof(REAL4TimeSeries) );
  memset( polResponse.pCross, 0, sizeof(REAL4TimeSeries) );
  memset( polResponse.pScalar, 0, sizeof(REAL4TimeSeries) );
  LALSCreateVector( stat->statusPtr, &( polResponse.pPlus->data ),
                    nMax );
  BEGINFAIL( stat ) {
    LALFree( polResponse.pPlus );
    LALFree( polResponse.pCross );
    LALFree( polResponse.pScalar );
    TRY( LALDDestroyVector( stat->statusPtr, &delay ), stat );
  } ENDFAIL( stat );
  LALSCreateVector( stat->statusPtr, &( polResponse.pCross->data ),
                    nMax );
  BEGINFAIL( stat ) {
    TRY( LALSDestroyVector( stat->statusPtr,
                            &( polResponse.pPlus->data ) ), stat );
    LALFree( polResponse.pPlus );
    LALFree( polResponse.pCross );
    LALFree( polResponse.pScalar );
    TRY( LALDDestroyVector( stat->statusPtr, &delay ), stat );
  } ENDFAIL( stat );
  LALSCreateVector( stat->statusPtr, &( polResponse.pScalar->data ),
                    nMax );
  BEGINFAIL( stat ) {
    TRY( LALSDestroyVector( stat->statusPtr,
                            &( polResponse.pPlus->data ) ), stat );
    TRY( LALSDestroyVector( stat->statusPtr,
                            &( polResponse.pCross->data ) ), stat );
    LALFree( polResponse.pPlus );
    LALFree( polResponse.pCross );
    LALFree( polResponse.pScalar );
    TRY( LALDDestroyVector( stat->statusPtr, &delay ), stat );
  } ENDFAIL( stat );
  plusData = polResponse.pPlus->data->data;
  crossData = polResponse.pCross->data->data;
  INT4 plusLen = polResponse.pPlus->data->length;
  INT4 crossLen = polResponse.pCross->data->length;
  if ( plusLen != crossLen ) {
    XLALPrintError ("plusLen = %d != crossLen = %d\n", plusLen, crossLen );
    ABORT ( stat, SIMULATECOHERENTGWH_EBAD, SIMULATECOHERENTGWH_MSGEBAD );
  }

  if ( detector->site ) {
    LALSource polSource;     /* position and polarization angle */
    LALDetAndSource input;            /* response input structure */
    LALTimeIntervalAndNSample params; /* response parameter structure */

    /* Arrange nested pointers, and set initial values. */
    polSource.equatorialCoords = source;
    polSource.orientation = (REAL8)( CWsignal->psi );
    input.pSource = &polSource;
    input.pDetector = detector->site;
    params.epoch = output->epoch;
    params.epoch.gpsSeconds -= dtPolBy2;
    params.deltaT = 2.0*dtPolBy2;
    params.nSample = nMax;

    /* Compute table of responses. */
    LALComputeDetAMResponseSeries( stat->statusPtr, &polResponse,
                                   &input, &params );
    BEGINFAIL( stat ) {
      TRY( LALSDestroyVector( stat->statusPtr,
                              &( polResponse.pPlus->data ) ), stat );
      TRY( LALSDestroyVector( stat->statusPtr,
                              &( polResponse.pCross->data ) ), stat );
      TRY( LALSDestroyVector( stat->statusPtr,
                              &( polResponse.pScalar->data ) ), stat );
      LALFree( polResponse.pPlus );
      LALFree( polResponse.pCross );
      LALFree( polResponse.pScalar );
      TRY( LALDDestroyVector( stat->statusPtr, &delay ), stat );
    } ENDFAIL( stat );
  } else {