LALInspiralPhasing1.c

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/*
*  Copyright (C) 2007 David Churches, B.S. Sathyaprakash
*
*  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 of the License, 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 with program; see the file COPYING. If not, write to the
*  Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
*  MA  02111-1307  USA
*/

/*  <lalVerbatim file="LALInspiralPhasing1CV">
Author: Sathyaprakash, B. S.
$Id: LALInspiralPhasing1.c,v 1.4 2007/06/08 14:41:49 bema Exp $
</lalVerbatim>  */

/*  <lalLaTeX>

\subsection{Module \texttt{LALInspiralPhasing1.c}}
This module is used to set the phase of the waveform so that
it is equal to the user specified phase $\phi_0$ when the `velocity' of the
system is equal to $v.$ 

\subsubsection*{Prototypes}
\vspace{0.1in}
\input{LALInspiralPhasing1CP}
\index{\verb&LALInspiralPhasing1()&}

\subsubsection*{Description}

The function \texttt{LALInspiralPhasing1} calculates the phase $\phi(v)$ using
the phasing formula,
\begin{equation}
\phi(v) =  \phi_{0} - 2 \int_{v_{0}}^{v} v^{3} \frac{E'(v)}{{\cal F}(v)} \, dv \,\,.
\label{phiofv}
\end{equation}
\texttt{LALInspiralPhasing1} calculates $\phi(v)$, given $\phi_{0}$, $v_{0}$,  
$v$, $E^{\prime}(v)$ and $\mathcal{F}(v)$.  The user can specify the phase to
be of a particular value at an arbitrary point on the waveform when the
post-Newtonian evolution variable $v$ reaches a specific value. Choosing
$v=v_0,$ the initial velocity, means that the initial phase of the wave is $\phi_0;$
Choosing $v=v_{\rm lso}$ means that the phase at the last stable orbit is $\phi_0$ and
so on. 

\subsubsection*{Algorithm}
Numerical integration.

\subsubsection*{Uses}

\texttt{LALDRombergIntegrate}

\subsubsection*{Notes}

\vfill{\footnotesize\input{LALInspiralPhasing1CV}}

</lalLaTeX>  */

#include <math.h>
#include <lal/LALStdlib.h>
#include <lal/LALInspiral.h>
#include <lal/Integrate.h>

NRCSID (LALINSPIRALPHASING1C, "$Id: LALInspiralPhasing1.c,v 1.4 2007/06/08 14:41:49 bema Exp $"); 

/*  <lalVerbatim file="LALInspiralPhasing1CP"> */
void 
LALInspiralPhasing1 (
   LALStatus *status,
   REAL8     *phiofv,
   REAL8     v,
   void      *params
   )
{ /* </lalVerbatim>  */

   void *funcParams;
   DIntegrateIn intinp;
   PhiofVIntegrandIn in2;
   InspiralPhaseIn *in1;
   REAL8 sign;
   REAL8 answer;

   INITSTATUS (status, "LALInspiralPhasing1", LALINSPIRALPHASING1C);
   ATTATCHSTATUSPTR (status);

   ASSERT (phiofv, status, LALINSPIRALH_ENULL, LALINSPIRALH_MSGENULL);
   ASSERT (params, status, LALINSPIRALH_ENULL, LALINSPIRALH_MSGENULL);
   ASSERT (v > 0., status, LALINSPIRALH_ESIZE, LALINSPIRALH_MSGESIZE);
   ASSERT (v < 1., status, LALINSPIRALH_ESIZE, LALINSPIRALH_MSGESIZE);

   sign = 1.0;

   in1 = (InspiralPhaseIn *) params;

   intinp.function = LALInspiralPhiofVIntegrand;
   intinp.xmin = in1->v0;
   intinp.xmax = v;
   intinp.type = ClosedInterval;

   in2.dEnergy = in1->dEnergy;
   in2.flux = in1->flux;
   in2.coeffs = in1->coeffs;

   funcParams = (void *) &in2;

   if (v==in1->v0) {
      *phiofv = in1->phi0;
      DETATCHSTATUSPTR (status);
      RETURN (status);
   }

   if(in1->v0 > v) {
      intinp.xmin = v;
      intinp.xmax = in1->v0;
      sign = -1.0;
   }

   LALDRombergIntegrate (status->statusPtr, &answer, &intinp, funcParams);
   CHECKSTATUSPTR (status);

   *phiofv = in1->phi0 - 2.0*sign*answer;

   DETATCHSTATUSPTR (status);
   RETURN (status);
}

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