XLALAddBinaryTimes: fixed root-finding accuracy to a sensible requirement

- require maximal CW-phase error of 1e-3
- fixes #1357
Original: df54e62c43ff8b67bb899c8121eb5d3586b1419f

lalpulsar/src/SSBtimes.c

@@ -30,7 +30,6 @@
 #include <gsl/gsl_roots.h>
 
 /*---------- local DEFINES ----------*/
-#define EA_ACC          1E-9                    /* the timing accuracy of LALGetBinaryTimes in seconds */
 
 /*----- Macros ----- */
 
@@ -297,6 +296,7 @@ XLALAddBinaryTimes ( SSBtimes **tSSBOut,			//!< [out] reference-time offsets in
   REAL8 sinw 	= sin ( argp );		/* the sin and cos of the argument of periapsis */
   REAL8 cosw 	= cos ( argp );
   REAL8 n    	= LAL_TWOPI / Porb;
+  REAL8 Freq    = Doppler->fkdot[0];
 
   REAL8 refTimeREAL8 = XLALGPSGetREAL8 ( &tSSBIn->refTime );
 
@@ -305,7 +305,10 @@ XLALAddBinaryTimes ( SSBtimes **tSSBOut,			//!< [out] reference-time offsets in
   REAL8 B = n * asini * sinw;			// see Eq.(eq:defB)
   REAL8 tp = XLALGPSGetREAL8 ( &(Doppler->tp) );
   REAL8 Tp = tp + asini * sinw * (1 - e);	// see Eq.(eq:defTPeri)
-  REAL8 acc = LAL_TWOPI * EA_ACC / Porb;   // root-finding accuracy, EA_ACC represents the required timing precision in seconds
+
+  REAL8 maxPhaseErr = 1e-3;			// maximal allowed CW phase-error due to error in E
+  REAL8 epsabs = maxPhaseErr / ( Freq * Porb);  // absolute root-finding accuracy required on E
+  REAL8 epsrel = 0;				// no constraint on relative accuracy
 
   /* loop over the SFTs i */
   for ( UINT4 i = 0; i < numSteps; i++ )
@@ -340,14 +343,14 @@ XLALAddBinaryTimes ( SSBtimes **tSSBOut,			//!< [out] reference-time offsets in
             E_i = gsl_root_fsolver_root(s);
             E_lo = gsl_root_fsolver_x_lower (s);
             E_hi = gsl_root_fsolver_x_upper (s);
-            status = gsl_root_test_interval ( E_lo, E_hi, acc, 0 );
+            status = gsl_root_test_interval ( E_lo, E_hi, epsabs, epsrel );
 
             if (status == GSL_SUCCESS) { XLALPrintInfo ("Converged:\n"); }
-            XLALPrintInfo ("%5d [%.7f, %.7f] %.7f %+10.7g %10.7g\n", iter, E_lo, E_hi, E_i, acc, E_hi - E_lo);
+            XLALPrintInfo ("%5d [%.7f, %.7f] %.7f %+10.7g %10.7g\n", iter, E_lo, E_hi, E_i, epsabs, E_hi - E_lo);
 
           } while ( (status == GSL_CONTINUE) && (iter < max_iter) );
 
-        XLAL_CHECK ( status == GSL_SUCCESS, XLAL_EMAXITER, "Eccentric anomaly: failed to converge within %d iterations\n", max_iter );
+        XLAL_CHECK ( status == GSL_SUCCESS, XLAL_EMAXITER, "Eccentric anomaly: failed to converge to epsabs=%g within %d iterations\n", epsabs, max_iter );
         gsl_root_fsolver_free(s);
       } // gsl-root finding block
 

lalpulsar/test/BinarySSBTimesTest.c

@@ -183,6 +183,7 @@ main ( int argc, char *argv[] )
   MultiSSBtimes *multiBinary_test = NULL;
   PulsarDopplerParams doppler;
   memset(&doppler, 0, sizeof(doppler));
+  doppler.fkdot[0] = 100;
   doppler.tp = orbit.tp;
   doppler.argp = orbit.argp;
   doppler.asini = orbit.asini;