smurf: Allow convergence to be specified by max change rather than me…

…an change

Useful if you are using numiter = ast.skip + 1 (i.e. all "preparatory"
iterations and no "real" iterations).

applications/smurf/defaults/smurf_makemap.def

@@ -1555,19 +1555,32 @@ itermap = 0
 #  Type: 	real
 #  Default: 	0.05
 #  Purpose: 	Specifies when to stop iterating.
-#  Description: If the normalised mean change between the maps created on
-#		subsequent iterations falls below the value of maptol, then the
-#		map-maker performs one more iteration and then terminates. Only
-#		used if parameter "numiter" is negative. The normalised mean
-#		change between maps is defined as the mean of the absolute
-#		change in map pixel value, averaged over all pixels within the
-#		region of the AST mask (if any, see parameter "ast.zero_mask",
-#		etc), and normalised by the RMS of the square root of the
-#		pixel variances. Compared to parameter "chitol", this is much
-#		more like a "by eye" test, that will stop the solution when
-#		the map stops changing.
+#  Description: If the normalised change (either the mean or maximum change -
+#               see parameter "maptol_mean") between the maps created on
+#               subsequent iterations falls below the value of maptol, then the
+#               map-maker performs one more iteration and then terminates. Only
+#               used if parameter "numiter" is negative. The normalised mean
+#               (or maximum) change between maps is defined as the mean (or
+#               maximum) of the absolute change in map pixel value, taken
+#               over all pixels within the region of the AST mask (if any,
+#               see parameter "ast.zero_mask", etc), and normalised by the RMS
+#               of the square root of the pixel variances. Compared to parameter
+#               "chitol", this is much more like a "by eye" test, that will stop
+#               the solution when the map stops changing.
 maptol = 0.05
 
+#-----------------------------------------------------------------
+#  Name: 	maptol_mean
+#  Type: 	integer
+#  Default: 	1
+#  Purpose: 	Specifies when to stop iterating.
+#  Description: If this value is non-zero, then the value specified by
+#               parameter "maptol" defines a target value for the mean
+#               change in normalised pixel value between iterations.
+#               Otherwise, "maptol"  defines a target value for the
+#               maximum change in normalised pixel value between iterations.
+maptol_mean = 1
+
 #-----------------------------------------------------------------
 #  Name: 	maxlen
 #  Type: 	integer

applications/smurf/libsmf/smf_iteratemap.c

@@ -618,6 +618,7 @@ void smf_iteratemap( ThrWorkForce *wf, const Grp *igrp, const Grp *iterrootgrp,
   double mapchange_mean=0;      /* Mean change in map */
   double mapchange_max=0;       /* Maximum change in the map */
   double maptol=VAL__BADD;      /* map change tolerance for stopping */
+  int maptol_mean;              /* Use mean map change instead of max map change? */
   double *mapweights=NULL;      /* Weight for each pixel including chunk weight */
   double *mapweightsq=NULL;     /* Sum of bolometer weights squared */
   dim_t maxconcat;              /* Longest continuous chunk that fits in mem.*/
@@ -676,6 +677,7 @@ void smf_iteratemap( ThrWorkForce *wf, const Grp *igrp, const Grp *iterrootgrp,
   size_t try;                   /* Try to concatenate this many samples */
   size_t tstride;               /* Time stride */
   struct timeval tv1, tv2;      /* Timers */
+  double tol;                   /* Map change value to compare to maptol */
   int untilconverge=0;          /* Set if iterating to convergence */
   int varmapmethod=0;           /* Method for calculating varmap */
   dim_t whichast=0;             /* Model index of AST (must be specified) */
@@ -800,6 +802,9 @@ void smf_iteratemap( ThrWorkForce *wf, const Grp *igrp, const Grp *iterrootgrp,
                FUNC_NAME ": MAPTOL is ^MAPTOL, must be > 0", status);
       }
 
+      /* Does maptol refer to mean map change or max map change? */
+      astMapGet0I( keymap, "MAPTOL_MEAN", &maptol_mean );
+
       /* Number of iterations */
       astMapGet0I( keymap, "NUMITER", &numiter );
       if( numiter == 0 ) {
@@ -2406,8 +2411,10 @@ void smf_iteratemap( ThrWorkForce *wf, const Grp *igrp, const Grp *iterrootgrp,
              convergence has been reached (i.e. when quit=0).  We do not
              allow convergence to be reached until we have done at least
              one iteration in which the AST model was not skipped. */
+
+          tol = maptol_mean ? mapchange_mean : mapchange_max;
           if( untilconverge &&
-              ( ( (maptol!=VAL__BADD) && (mapchange_mean > maptol) ) ||
+              ( ( (maptol!=VAL__BADD) && (tol > maptol) ) ||
                 last_skipped ) && quit == -1 ) {
             /* Map hasn't converged yet */
             converged=0;