Changeset 36086 for trunk/psphot/src

Timestamp:

Aug 31, 2013, 6:02:26 AM (13 years ago)

Author:

eugene

Message:

merge changes from EAM branch (update tap script for galaxies; count deblended satstars for log message; scale down EXT window a bit for speed (OK?); enable interactive mode for PCM fitting; allow NONCONVERGE extended fit models to succeed; init EXT model fits with EXT_AND_SKY just in case; extra verbosity and various experiments on the index iterations)

Location:

trunk/psphot

Files:

• . (modified) (1 prop)
• src (modified) (1 prop)
• src/psphotBlendFit.c (modified) (3 diffs)
• src/psphotDeblendSatstars.c (modified) (3 diffs)
• src/psphotExtendedSourceFits.c (modified) (10 diffs)
• src/psphotRadiusChecks.c (modified) (1 diff)
• src/psphotSourceFits.c (modified) (6 diffs)
• src/psphotStackImageLoop.c (modified) (1 prop)

trunk/psphot/src/psphotBlendFit.c

@@ -273 +273 @@
         pmSource *source = sources->data[i];
 
+# if (0)
         int TEST_ON = false;
-# if (0)
 # define TEST_X 653
 # define TEST_Y 466
@@ -342 +342 @@
         if (source->mode & PM_SOURCE_MODE_EXT_LIMIT) {
             if (psphotFitBlob (readout, source, newSources, psf, fitOptions, maskVal, markVal)) {
+# if (PS_TRACE_ON)
                 if (TEST_ON) {
                     psTraceSetLevel("psLib.math.psMinimizeLMChi2", 0);
                 }
+# endif
                 psTrace ("psphot", 5, "source at %7.1f, %7.1f is ext", source->peak->xf, source->peak->yf);
                 Next ++;
@@ -351 +353 @@
         } else {
             if (psphotFitBlend (readout, source, psf, fitOptions, maskVal, markVal)) {
+# if (PS_TRACE_ON)
                 if (TEST_ON) {
                     psTraceSetLevel("psLib.math.psMinimizeLMChi2", 0);
                 }
+# endif
                 source->type = PM_SOURCE_TYPE_STAR;
                 psTrace ("psphot", 5, "source at %7.1f, %7.1f is psf", source->peak->xf, source->peak->yf);

trunk/psphot/src/psphotDeblendSatstars.c

@@ -128 +128 @@
     // int display = psphotKapaChannel (1);
     // psphotVisualScaleImage (display, (psImage *) source->pixels->parent, NULL, "image", 1.0, 0);
+
+    int Nsatstar = 0;
 
     // examine sources in decreasing SN order
@@ -179 +181 @@
         source->mode2 |= PM_SOURCE_MODE2_SATSTAR_PROFILE; // and we have in fact subtracted the profile
 
+        Nsatstar ++;
+
         // XXX visualize, model, and subtract
         // if (!psphotVisualRadialProfileSatstar (source, maskVal)) {
@@ -192 +196 @@
     psFree (index);
 
-    psLogMsg ("psphot", PS_LOG_INFO, "deblend satstar: %f sec\n", psTimerMark ("psphot.deblend.sat"));
+    psLogMsg ("psphot", PS_LOG_INFO, "deblend %d satstars: %f sec\n", Nsatstar, psTimerMark ("psphot.deblend.sat"));
     return true;
 }

trunk/psphot/src/psphotExtendedSourceFits.c

@@ -65 +65 @@
     psphotVisualShowImage(readout);
 
+    // psphotSaveImage (NULL, readout->image, "test.01.fits");
+
     pmDetections *detections = psMetadataLookupPtr (&status, readout->analysis, "PSPHOT.DETECTIONS");
     psAssert (detections, "missing detections?");
@@ -123 +125 @@
     }
 
+    // perform full extended source non-linear fits?
+    bool isInteractive = psMetadataLookupBool (&status, recipe, "EXTENDED_SOURCE_FITS_INTERACTIVE");
+    if (!status) isInteractive = false;
+
     // Define source fitting parameters for extended source fits
     pmSourceFitOptions *fitOptions = pmSourceFitOptionsAlloc();
-    fitOptions->mode           = PM_SOURCE_FIT_EXT;
+    fitOptions->mode           = PM_SOURCE_FIT_EXT_AND_SKY;
     fitOptions->saveCovariance = true;  // XXX make this a user option?
     fitOptions->covarFactor    = psImageCovarianceFactorForAperture(readout->covariance, 10.0); // Covariance matrix
@@ -134 +140 @@
     fitOptions->gainFactorMode   = gainFactorMode;
     fitOptions->chisqConvergence = chisqConvergence;
+    fitOptions->isInteractive    = isInteractive;
 
     // maskVal is used to test for rejected pixels, and must include markVal
@@ -296 +303 @@
             PS_ARRAY_ADD_SCALAR(job->args, 0, PS_TYPE_S32); // this is used as a return value for Nfail
 
-// set this to 0 to run without threading
-# if (1)            
-            if (!psThreadJobAddPending(job)) {
-                psError(PS_ERR_UNKNOWN, false, "Unable to guess model.");
-                psFree(AnalysisRegion);
-                psFree (fitOptions);
-                psFree (models);
-                psphotSersicModelClassCleanup();
-                return false;
-            } 
-# else
-            if (!psphotExtendedSourceFits_Threaded(job)) {
-                psError(PS_ERR_UNKNOWN, false, "Unable to guess model.");
-                psFree(AnalysisRegion);
-                psFree (fitOptions);
-                psFree (models);
-                psphotSersicModelClassCleanup();
-                return false;
+// XXX TEST 
+            if (!isInteractive) {
+                if (!psThreadJobAddPending(job)) {
+                    psError(PS_ERR_UNKNOWN, false, "Unable to guess model.");
+                    psFree(AnalysisRegion);
+                    psFree (fitOptions);
+                    psFree (models);
+                    psphotSersicModelClassCleanup();
+                    return false;
+                } 
+            } else {
+                // run without threading
+                if (!psphotExtendedSourceFits_Threaded(job)) {
+                    psError(PS_ERR_UNKNOWN, false, "Unable to guess model.");
+                    psFree(AnalysisRegion);
+                    psFree (fitOptions);
+                    psFree (models);
+                    psphotSersicModelClassCleanup();
+                    return false;
+                }
+                psScalar *scalar = NULL;
+                scalar = job->args->data[9];
+                Next += scalar->data.S32;
+                scalar = job->args->data[10];
+                Nconvolve += scalar->data.S32;
+                scalar = job->args->data[11];
+                NconvolvePass += scalar->data.S32;
+                scalar = job->args->data[12];
+                Nplain += scalar->data.S32;
+                scalar = job->args->data[13];
+                NplainPass += scalar->data.S32;
+                scalar = job->args->data[14];
+                Nfaint += scalar->data.S32;
+                scalar = job->args->data[15];
+                Nfail += scalar->data.S32;
+                psFree(job->args->data[3]); // iterator allocated above
+                psFree(job);
             }
-            psScalar *scalar = NULL;
-            scalar = job->args->data[9];
-            Next += scalar->data.S32;
-            scalar = job->args->data[10];
-            Nconvolve += scalar->data.S32;
-            scalar = job->args->data[11];
-            NconvolvePass += scalar->data.S32;
-            scalar = job->args->data[12];
-            Nplain += scalar->data.S32;
-            scalar = job->args->data[13];
-            NplainPass += scalar->data.S32;
-            scalar = job->args->data[14];
-            Nfaint += scalar->data.S32;
-            scalar = job->args->data[15];
-            Nfail += scalar->data.S32;
-            psFree(job->args->data[3]); // iterator allocated above
-            psFree(job);
-# endif
         }
 
@@ -378 +386 @@
     psphotSersicModelClassCleanup();
 
+    // psphotSaveImage (NULL, readout->image, "test.02.fits");
+
     psphotVisualShowResidualImage (readout, false);
 
@@ -521 +531 @@
                   psFree (source->modelFlux);
                   source->modelFlux = NULL;
+                  // if ((fabs(source->peak->xf - 2572) < 20) && (fabs(source->peak->yf - 5874) < 20)) {
+                  //   fprintf (stderr, "test object\n");
+                  // }
+
                   modelFit = psphotFitEXT (modelFit, readout, source, fitOptions, modelType, maskVal, markVal);
                   if (!modelFit) {
@@ -544 +558 @@
                       float Ymax = PAR[PM_PAR_YPOS] + 0.5*PAR[PM_PAR_LENGTH]*cos(PAR[PM_PAR_THETA]);
 
-                      if (false && (source->peak->xf > 1100) && 
-                          (source->peak->xf < 1400) && 
-                          (source->peak->yf < 245)) {
+                      if ((fabs(source->peak->xf - 2572) < 20) && (fabs(source->peak->yf - 5874) < 20)) {
                           fprintf (stderr, "src vs fit : %d %d - %d %d | %f %f - %f %f\n", 
                                    source->pixels->col0, source->pixels->row0, 
@@ -579 +591 @@
 
             if (model->flags & (PM_MODEL_STATUS_BADARGS)) continue;
-            if (model->flags & (PM_MODEL_STATUS_NONCONVERGE)) continue;
+            // if (model->flags & (PM_MODEL_STATUS_NONCONVERGE)) continue;
             if (model->flags & (PM_MODEL_STATUS_OFFIMAGE)) continue;
 
@@ -598 +610 @@
           pmSourceCacheModel (source, maskVal);
 
+          pmModel *model = source->modelFits->data[0];
+          int flags = 0xffffffff;
+          if (model) {
+            flags = model->flags;
+          }
+
+          fprintf (stderr, "failed to fit extended source model to object %d @ %f, %f (%x)\n", source->id, source->moments->Mx, source->moments->My, flags);
           pmSourceSub (source, PM_MODEL_OP_FULL, maskVal);
 
@@ -615 +634 @@
         // cache the model flux
         if (source->modelEXT->isPCM) {
+            // fprintf (stderr, "subtract PCM extended source model for object %d @ %f, %f\n", source->id, source->moments->Mx, source->moments->My);
             pmPCMCacheModel (source, maskVal, psfSize);
         } else {
+            // fprintf (stderr, "subtract non-PCM extended source model for object %d @ %f, %f\n", source->id, source->moments->Mx, source->moments->My);
             pmSourceCacheModel (source, maskVal);
         }

trunk/psphot/src/psphotRadiusChecks.c

@@ -171 +171 @@
 # undef MIN_WINDOW
 
+// XXX EAM : 20130724 : for a test, double the window size parameters
+// # define MIN_WINDOW 10.0
+// # define SCALE1 7.0
 # define MIN_WINDOW 5.0
-# define SCALE1 5.0
+# define SCALE1 3.0
 # define PAD_WINDOW 3.0
 

trunk/psphot/src/psphotSourceFits.c

@@ -559 +559 @@
 
 # define TIMING 0
+# define EXTRA_VERBOSE 0
+
+bool psphotSersicModelGuessPCM (pmPCMdata *pcm, pmSource *source, psImageMaskType maskVal, float psfSize);
+bool psphotFitSersicShapeAndIndex (pmPCMdata *pcm, pmReadout *readout, pmSource *source, pmSourceFitOptions *fitOptions, psImageMaskType maskVal, psImageMaskType markVal, int psfSize);
+bool psphotFitSersicShapeAndIndexGrid (pmPCMdata *pcm, pmReadout *readout, pmSource *source, pmSourceFitOptions *fitOptions, psImageMaskType maskVal, psImageMaskType markVal, int psfSize);
+bool psphotFitSersicShapeAndIndexGridAuto (pmPCMdata *pcm, pmReadout *readout, pmSource *source, pmSourceFitOptions *fitOptions, psImageMaskType maskVal, psImageMaskType markVal, int psfSize);
 
 pmModel *psphotFitPCM (pmReadout *readout, pmSource *source, pmSourceFitOptions *fitOptions, pmModelType modelType, psImageMaskType maskVal, psImageMaskType markVal, int psfSize) {
@@ -580 +586 @@
 
     float t1, t2, t4, t5;
+    t1 = t2 = t4 = t5 = 0.0;
     if (TIMING) { psTimerStart ("psphotFitPCM"); }
+
+    if (modelType == pmModelClassGetType("PS_MODEL_SERSIC")) {
+        options.mode = PM_SOURCE_FIT_NO_INDEX; // XXX note that there may be a conflict with psphotExtendedSourceFits.c:133
+        options.mode = PM_SOURCE_FIT_EXT_AND_SKY;
+        // if we are ever (in a given psphot implementation) going to fit a parameter, we must set the options here to include
+        // that parameter (otherwise pmPCMupdate will fail to allocate the dmodelFlux image)
+        // thus, if the sersic analysis below uses an index fit, need to use this EXT_AND_SKY mode for init
+    } else {
+        options.mode = PM_SOURCE_FIT_EXT_AND_SKY;
+    }
 
     pmPCMdata *pcm = pmPCMinit (source, &options, model, maskVal, psfSize);
@@ -594 +611 @@
     if (modelType == pmModelClassGetType("PS_MODEL_SERSIC")) {
         // use the source moments, etc to guess basic model parameters
-        if (!psphotSersicModelClassGuessPCM (pcm, source)) {
+        if (!psphotSersicModelGuessPCM (pcm, source, maskVal, psfSize)) {
             psFree (pcm);
             model->flags |= PM_MODEL_STATUS_BADARGS;
+            return model;
+        }
+        if (TIMING) { t2 = psTimerMark ("psphotFitPCM"); }
+
+        // psphotFitSersicShapeAndIndex (pcm, readout, source, fitOptions, maskVal, markVal, psfSize);
+        options.mode = PM_SOURCE_FIT_NO_INDEX;
+        if (!psphotFitSersicShapeAndIndexGridAuto (pcm, readout, source, &options, maskVal, markVal, psfSize)) {
+            psFree (pcm);
+            model->flags |= PM_MODEL_STATUS_BADARGS;
+            psError(PS_ERR_UNKNOWN, true, "Failed to find a index & shape");
+            psErrorClear (); // clear the polynomial error
             return model;
         }
@@ -608 +636 @@
     }
 
-    if (TIMING) { t2 = psTimerMark ("psphotFitPCM"); }
-
-    if (modelType == pmModelClassGetType("PS_MODEL_SERSIC")) {
-        options.mode = PM_SOURCE_FIT_NO_INDEX;
-    } else {
-        options.mode = PM_SOURCE_FIT_EXT;
-    }
-    // update the pcm elements if we have changed the circumstance (options.mode or source->pixels)
-    pmPCMupdate(pcm, source, &options, model);
     if (TIMING) { t4 = psTimerMark ("psphotFitPCM"); }
 
@@ -629 +648 @@
         fprintf (stderr, "psphotFitPCM : nIter: %2d, radius: %6.1f, npix: %5d of %5d, t1: %6.4f, t2: %6.4f, t4: %6.4f, t5: %6.4f\n", model->nIter, model->fitRadius, model->nPix, nPixBig, t1, t2, t4, t5);
     }
-
-    // psTraceSetLevel("psLib.math.psMinimizeLMChi2", 0);
+    if (EXTRA_VERBOSE && !TIMING) {
+        int nPixBig = source->pixels->numCols * source->pixels->numRows;
+        float *PAR = model->params->data.F32;
+        fprintf (stderr, "source %d : %f - %f %f - %f %f %f - %f | nIter: %2d, radius: %6.1f, npix: %5d of %5d, chisq %f\n", source->id, PAR[7], PAR[2], PAR[3], PAR[4], PAR[5], PAR[6], PAR[1], model->nIter, model->fitRadius, model->nPix, nPixBig, model->chisqNorm);
+    }
+
     psFree (pcm);
 
@@ -748 +771 @@
     return true;
 }
+
+// float indexGuessInv[] = {0.5, 0.33, 0.25, 0.167, 0.125, 0.083};
+float indexGuessInv[] = {0.5, 0.4, 0.3, 0.25, 0.20, 0.15, 0.125};
+# define N_INDEX_GUESS_INV 7
+
+// float reffGuess[] = {3.0, 10.0, 20.0, 30.0, 40.0};
+float reffGuess[] = {0.5, 0.75, 1.0, 1.4, 2.0};
+# define N_REFF_GUESS 5
+
+// A sersic model is very sensitive to the index.  attempt to find the index first by grid search in just the index
+// for a sersic model, attempt to fit just the index and normalization with a modest number of iterations
+bool psphotSersicModelGuessPCM (pmPCMdata *pcm, pmSource *source, psImageMaskType maskVal, float psfSize) {
+
+    // we get a reasonable guess from:
+    // * Reff = Kron R1
+    // * Rmajor / Rminor & Theta from moments
+    // * Io from total Kron flux
+
+    // the guesses are used to fill in PAR:
+    psF32 *PAR = pcm->modelConv->params->data.F32;
+
+    // convert the moments to Major,Minor,Theta
+    psEllipseMoments moments;
+
+    if (!isfinite(source->moments->Mrf)) return false;
+    if (!isfinite(source->moments->Mxx)) return false;
+    if (!isfinite(source->moments->Mxy)) return false;
+    if (!isfinite(source->moments->Myy)) return false;
+
+    moments.x2 = source->moments->Mxx;
+    moments.y2 = source->moments->Myy;
+    moments.xy = source->moments->Mxy;
+    
+    // limit axis ratio < 20.0
+    psEllipseAxes momentAxes = psEllipseMomentsToAxes (moments, 20.0);
+
+    if (0) {
+        psEllipseAxes guessAxes;
+        guessAxes.major = source->moments->Mrf;
+        guessAxes.minor = (momentAxes.minor / momentAxes.minor) * guessAxes.major;
+        guessAxes.theta = momentAxes.theta;
+
+        if (!isfinite(guessAxes.major)) return false;
+        if (!isfinite(guessAxes.minor)) return false;
+        if (!isfinite(guessAxes.theta)) return false;
+
+        // convert the major,minor,theta to shape parameters for an Reff-like model
+        pmModelAxesToParams (&PAR[PM_PAR_SXX], &PAR[PM_PAR_SXY], &PAR[PM_PAR_SYY], guessAxes, true);
+    }
+
+    // set the model position
+    if (!pmModelSetPosition(&PAR[PM_PAR_XPOS], &PAR[PM_PAR_YPOS], source)) {
+      return false;
+    }
+
+    // sky is zero (no longer fitted, but not yet deprecated)
+    PAR[PM_PAR_SKY]  = 0.0;
+
+    // for the index loop, use Io = 1.0, use fitted values to determine Io
+    PAR[PM_PAR_I0] = 1.0;
+
+    float xMin = NAN;
+    float iMin = NAN;
+    float sMin = NAN;
+    float rMin = NAN;
+
+    // loop over index and Reff, keeping the ARatio and Theta constant?
+    // loop over index guesses and find the best fit
+    for (int j = 0; j < N_REFF_GUESS; j++) {
+
+        psEllipseAxes guessAxes;
+        guessAxes.major = reffGuess[j] * source->moments->Mrf;
+        guessAxes.minor = guessAxes.major * (momentAxes.minor / momentAxes.major);
+        guessAxes.theta = momentAxes.theta;
+
+        if (!isfinite(guessAxes.major)) return false;
+        if (!isfinite(guessAxes.minor)) return false;
+        if (!isfinite(guessAxes.theta)) return false;
+
+        // convert the major,minor,theta to shape parameters for an Reff-like model
+        pmModelAxesToParams (&PAR[PM_PAR_SXX], &PAR[PM_PAR_SXY], &PAR[PM_PAR_SYY], guessAxes, true);
+
+        for (int i = 0; i < N_INDEX_GUESS_INV; i++) {
+            PAR[PM_PAR_7] = indexGuessInv[i];
+
+            // generated the modelFlux
+            pmPCMMakeModel (source, pcm->modelConv, maskVal, psfSize);
+        
+            float YY = 0.0;
+            float YM = 0.0;
+            float MM = 0.0;
+            bool usePoisson = false;
+
+            for (int iy = 0; iy < source->pixels->numRows; iy++) {
+                for (int ix = 0; ix < source->pixels->numCols; ix++) {
+                    // skip masked points
+                    if (source->maskObj->data.PS_TYPE_IMAGE_MASK_DATA[iy][ix]) {
+                        continue;
+                    }
+                    // skip zero-variance points
+                    if (source->variance->data.F32[iy][ix] == 0) {
+                        continue;
+                    }
+                    // skip nan value points
+                    if (!isfinite(source->pixels->data.F32[iy][ix])) {
+                        continue;
+                    }
+
+                    float fy = source->pixels->data.F32[iy][ix];
+                    float fm = source->modelFlux->data.F32[iy][ix];
+                    float wt = (usePoisson) ? 1.0 / source->variance->data.F32[iy][ix] : 1.0;
+
+                    YY += PS_SQR(fy) * wt;
+                    YM += fm * fy * wt;
+                    MM += PS_SQR(fm) * wt;
+                }
+            }
+
+            float Io = YM / MM;
+            float Chisq = YY - 2 * Io * YM + Io * Io * MM;
+            if (isnan(xMin) || (Chisq < xMin)) {
+                xMin = Chisq;
+                iMin = Io;
+                sMin = indexGuessInv[i];
+                rMin = reffGuess[j];
+            }
+            // fprintf (stderr, "%d | %f %f %f %f | %f %f %f %f", i, indexGuessInv[i], reffGuess[j], Io, Chisq, sMin, rMin, iMin, xMin);
+            // fprintf (stderr, "\n");
+        }
+    }
+
+    {
+        psEllipseAxes guessAxes;
+        guessAxes.major = rMin * source->moments->Mrf;
+        guessAxes.minor = guessAxes.major * (momentAxes.minor / momentAxes.major);
+        guessAxes.theta = momentAxes.theta;
+
+        if (!isfinite(guessAxes.major)) return false;
+        if (!isfinite(guessAxes.minor)) return false;
+        if (!isfinite(guessAxes.theta)) return false;
+
+        // convert the major,minor,theta to shape parameters for an Reff-like model
+        pmModelAxesToParams (&PAR[PM_PAR_SXX], &PAR[PM_PAR_SXY], &PAR[PM_PAR_SYY], guessAxes, true);
+    }
+
+    PAR[PM_PAR_I0] = iMin;
+    PAR[PM_PAR_7] = sMin;
+
+    return true;
+}
+
+// we have a set of guess parameters, do a small number of iterations fitting only SHAPE then only INDEX 
+bool psphotFitSersicShapeAndIndex (pmPCMdata *pcm, pmReadout *readout, pmSource *source, pmSourceFitOptions *fitOptions, psImageMaskType maskVal, psImageMaskType markVal, int psfSize) {
+
+    pmModel *model = pcm->modelConv;
+
+    assert (model->type == pmModelClassGetType("PS_MODEL_SERSIC"));
+
+    pmSourceFitOptions options = *fitOptions;
+    
+    for (int i = 0; i < 3; i++) {
+      // fit EXT (not PSF) model (set/unset the pixel mask)
+      options.mode = PM_SOURCE_FIT_SHAPE;
+      options.nIter = 2;
+
+      // update the pcm elements if we have changed the circumstance (here, options.mode)
+      pmPCMupdate(pcm, source, &options, model);
+      
+      pmSourceFitPCM (pcm, source, &options, maskVal, markVal, psfSize);
+      if (EXTRA_VERBOSE) {
+        float *PAR = model->params->data.F32;
+        fprintf (stderr, "%d >>> %d %f : %f - %f %f - %f %f %f - %f\n", source->id, model->nIter, model->chisqNorm, PAR[7], PAR[2], PAR[3], PAR[4], PAR[5], PAR[6], PAR[1]);
+      }
+      
+      // fit EXT (not PSF) model (set/unset the pixel mask)
+      options.mode = PM_SOURCE_FIT_INDEX;
+      // options.mode = PM_SOURCE_FIT_EXT_AND_SKY;
+      options.nIter = 30;
+      
+      // update the pcm elements if we have changed the circumstance (here, options.mode)
+      pmPCMupdate(pcm, source, &options, model);
+      
+      pmSourceFitPCM (pcm, source, &options, maskVal, markVal, psfSize);
+      if (EXTRA_VERBOSE) {
+        float *PAR = model->params->data.F32;
+        fprintf (stderr, "%d >>> %d %f : %f - %f %f - %f %f %f - %f\n", source->id, model->nIter, model->chisqNorm, PAR[7], PAR[2], PAR[3], PAR[4], PAR[5], PAR[6], PAR[1]);
+      }
+    }
+
+    // update the pcm elements if we have changed the circumstance (here, options.mode)
+    pmPCMupdate(pcm, source, fitOptions, model);
+
+    return true;
+}
+
+// we have a set of guess parameters, do a small number of iterations fitting only SHAPE then only INDEX 
+bool psphotFitSersicShapeAndIndexGridAuto (pmPCMdata *pcm, pmReadout *readout, pmSource *source, pmSourceFitOptions *fitOptions, psImageMaskType maskVal, psImageMaskType markVal, int psfSize) {
+
+    pmModel *model = pcm->modelConv;
+
+    assert (model->type == pmModelClassGetType("PS_MODEL_SERSIC"));
+
+    pmSourceFitOptions options = *fitOptions;
+    
+    psF32 *PAR = pcm->modelConv->params->data.F32;
+
+    options.mode = PM_SOURCE_FIT_SHAPE;
+    options.nIter = 7;
+    
+    // update the pcm elements if we have changed the circumstance (here, options.mode)
+    pmPCMupdate(pcm, source, &options, model);
+    
+    // we have been provided a guess at the index (P[7]) from the list of indexGuessInv
+
+    // find the matching indexGuessInv
+    int nStart = -1;
+    for (int i = 0; i < N_INDEX_GUESS_INV; i++) {
+        if (fabs(PAR[PM_PAR_7] - indexGuessInv[i]) < 0.01) {
+            nStart = i;
+            break;
+        }
+    }
+    if (nStart == -1) {
+        fprintf (stderr, "WARNING: could not find start guess %f\n", PAR[PM_PAR_7]);
+        return false;
+    }
+
+    psVector *chi2 = psVectorAllocEmpty (16, PS_TYPE_F32);
+    psVector *Sidx = psVectorAllocEmpty (16, PS_TYPE_F32);
+
+    PAR[PM_PAR_7] = indexGuessInv[nStart];
+    pmSourceFitPCM (pcm, source, &options, maskVal, markVal, psfSize);
+    if (EXTRA_VERBOSE) fprintf (stderr, "%d >>> %d %f : %f - %f %f - %f %f %f - %f\n", source->id, model->nIter, model->chisqNorm, PAR[7], PAR[2], PAR[3], PAR[4], PAR[5], PAR[6], PAR[1]);
+    psVectorAppend (Sidx, 100*PAR[PM_PAR_7]);
+    psVectorAppend (chi2, model->chisqNorm);
+
+    PAR[PM_PAR_7] = (nStart < N_INDEX_GUESS_INV - 1) ? 0.5*(indexGuessInv[nStart + 1] + indexGuessInv[nStart]) : 0.1;
+    pmSourceFitPCM (pcm, source, &options, maskVal, markVal, psfSize);
+    if (EXTRA_VERBOSE) fprintf (stderr, "%d >>> %d %f : %f - %f %f - %f %f %f - %f\n", source->id, model->nIter, model->chisqNorm, PAR[7], PAR[2], PAR[3], PAR[4], PAR[5], PAR[6], PAR[1]);
+    psVectorAppend (Sidx, 100*PAR[PM_PAR_7]);
+    psVectorAppend (chi2, model->chisqNorm);
+
+    PAR[PM_PAR_7] = (nStart > 0) ? 0.5*(indexGuessInv[nStart - 1] + indexGuessInv[nStart]) : 0.55;
+    pmSourceFitPCM (pcm, source, &options, maskVal, markVal, psfSize);
+    if (EXTRA_VERBOSE) fprintf (stderr, "%d >>> %d %f : %f - %f %f - %f %f %f - %f\n", source->id, model->nIter, model->chisqNorm, PAR[7], PAR[2], PAR[3], PAR[4], PAR[5], PAR[6], PAR[1]);
+    psVectorAppend (Sidx, 100*PAR[PM_PAR_7]);
+    psVectorAppend (chi2, model->chisqNorm);
+
+    if (chi2->data.F32[1] < chi2->data.F32[2]) {
+      if (nStart == N_INDEX_GUESS_INV - 1) {
+        PAR[PM_PAR_7] = 0.11;
+      } else {
+        PAR[PM_PAR_7] = indexGuessInv[nStart + 1];
+      }
+    } else {
+      if (nStart == 0) {
+        PAR[PM_PAR_7] = 0.52;
+      } else {
+        PAR[PM_PAR_7] = indexGuessInv[nStart - 1];
+      }
+    }
+
+    psPolynomial1D *poly = psPolynomial1DAlloc (PS_POLYNOMIAL_ORD, 2);
+    if (!psVectorFitPolynomial1D (poly, NULL, 0, chi2, NULL, Sidx)) {
+        psError(PS_ERR_UNKNOWN, true, "Failed to find a good chisq parabola");
+        psFree (chi2);
+        psFree (Sidx);
+        psFree (poly);
+        return false;
+    }
+
+    // where is the minimum of this polynomial fit?
+    float Smin = -0.5 * poly->coeff[1] / poly->coeff[2] / 100.0;
+
+    // constrain Smin to be in a valid range (1.0 - 0.1, corresponding to 0.5 (Gauss) to 5.0 (slightly peakier than Dev)
+    Smin = PS_MAX(PS_MIN(Smin, 1.0), 0.1);
+    PAR[PM_PAR_7] = Smin;
+
+    // return to the original fitting mode (fitOptions)
+    pmPCMupdate(pcm, source, fitOptions, model);
+
+    psFree (chi2);
+    psFree (Sidx);
+    psFree (poly);
+
+    return true;
+}
+
+ 
+// we have a set of guess parameters, do a small number of iterations fitting only SHAPE then only INDEX 
+bool psphotFitSersicShapeAndIndexGridAutoScaled (pmPCMdata *pcm, pmReadout *readout, pmSource *source, pmSourceFitOptions *fitOptions, psImageMaskType maskVal, psImageMaskType markVal, int psfSize) {
+
+    pmModel *model = pcm->modelConv;
+
+    assert (model->type == pmModelClassGetType("PS_MODEL_SERSIC"));
+
+    pmSourceFitOptions options = *fitOptions;
+    
+    psF32 *PAR = pcm->modelConv->params->data.F32;
+
+    options.mode = PM_SOURCE_FIT_SHAPE;
+    options.nIter = 5;
+    
+    // update the pcm elements if we have changed the circumstance (here, options.mode)
+    pmPCMupdate(pcm, source, &options, model);
+    
+    float parStart[8];
+    for (int i = 0; i < 8; i++) parStart[i] = PAR[i];
+
+    // we start with a guess at the index (P[7])
+
+    // get chisq for P[7], P[7]*1.1, P[7]*1.25 (or *0.75 depending on the result of 1.1)
+
+    psVector *chi2 = psVectorAllocEmpty (16, PS_TYPE_F32);
+    psVector *Sidx = psVectorAllocEmpty (16, PS_TYPE_F32);
+
+    PAR[PM_PAR_7] = parStart[7];
+    pmSourceFitPCM (pcm, source, &options, maskVal, markVal, psfSize);
+      if (EXTRA_VERBOSE) fprintf (stderr, "%d >>> %d %f : %f - %f %f - %f %f %f - %f\n", source->id, model->nIter, model->chisqNorm, PAR[7], PAR[2], PAR[3], PAR[4], PAR[5], PAR[6], PAR[1]);
+    psVectorAppend (Sidx, 100*PAR[PM_PAR_7]);
+    psVectorAppend (chi2, model->chisqNorm);
+
+    float fI = 1.1;
+    PAR[PM_PAR_7] = parStart[7]*fI;
+    pmSourceFitPCM (pcm, source, &options, maskVal, markVal, psfSize);
+      if (EXTRA_VERBOSE) fprintf (stderr, "%d >>> %d %f : %f - %f %f - %f %f %f - %f\n", source->id, model->nIter, model->chisqNorm, PAR[7], PAR[2], PAR[3], PAR[4], PAR[5], PAR[6], PAR[1]);
+    psVectorAppend (Sidx, 100*PAR[PM_PAR_7]);
+    psVectorAppend (chi2, model->chisqNorm);
+
+    if (chi2->data.F32[1] < chi2->data.F32[0]) {
+      fI = 1.3;
+    } else {
+      fI = 1.0 / 1.3;
+    }
+    
+    PAR[PM_PAR_7] = parStart[7]*fI;
+    pmSourceFitPCM (pcm, source, &options, maskVal, markVal, psfSize);
+      if (EXTRA_VERBOSE) fprintf (stderr, "%d >>> %d %f : %f - %f %f - %f %f %f - %f\n", source->id, model->nIter, model->chisqNorm, PAR[7], PAR[2], PAR[3], PAR[4], PAR[5], PAR[6], PAR[1]);
+    psVectorAppend (Sidx, 100*PAR[PM_PAR_7]);
+    psVectorAppend (chi2, model->chisqNorm);
+
+    // can we fit the 3 pts with a parabola?
+    int nTry = 0;
+    psPolynomial1D *poly = psPolynomial1DAlloc (PS_POLYNOMIAL_ORD, 2);
+    while (!psVectorFitPolynomial1D (poly, NULL, 0, chi2, NULL, Sidx)) {
+      psErrorClear (); // clear the polynomial error
+      if (nTry > 4) {
+        psError(PS_ERR_UNKNOWN, true, "Failed to find a good chisq parabola");
+        psFree (chi2);
+        psFree (Sidx);
+        psFree (poly);
+        return false;
+      }
+      fI = (fI < 1.0) ? fI / 1.3 : fI * 1.3;
+      PAR[PM_PAR_7] = parStart[7]*fI;
+      pmSourceFitPCM (pcm, source, &options, maskVal, markVal, psfSize);
+      if (EXTRA_VERBOSE) fprintf (stderr, "%d >>> %d %f : %f - %f %f - %f %f %f - %f\n", source->id, model->nIter, model->chisqNorm, PAR[7], PAR[2], PAR[3], PAR[4], PAR[5], PAR[6], PAR[1]);
+      psVectorAppend (Sidx, 100*PAR[PM_PAR_7]);
+      psVectorAppend (chi2, model->chisqNorm);
+      nTry ++;
+    }
+
+    // where is the minimum of this polynomial fit?
+    float Smin = -0.5 * poly->coeff[1] / poly->coeff[2] / 100.0;
+
+    // constrain Smin to be in a valid range (1.0 - 0.1, corresponding to 0.5 (Gauss) to 5.0 (slightly peakier than Dev)
+    Smin = PS_MAX(PS_MIN(Smin, 1.0), 0.1);
+    PAR[PM_PAR_7] = Smin;
+
+    // pmSourceFitPCM (pcm, source, &options, maskVal, markVal, psfSize);
+    // if (EXTRA_VERBOSE) fprintf (stderr, "%d >>> %d %f : %f - %f %f - %f %f %f - %f\n", source->id, model->nIter, model->chisqNorm, PAR[7], PAR[2], PAR[3], PAR[4], PAR[5], PAR[6], PAR[1]);
+    
+    //// for (int i = 0; i < 8; i++) PAR[i] = parStart[i];
+    //// 
+    //// for (float fI = 0.0; fI < 0.15; fI += 0.01) {
+    ////   PAR[PM_PAR_7] = parStart[7] - fI;
+    //// 
+    ////   // fit EXT (not PSF) model (set/unset the pixel mask)
+    ////   
+    ////   pmSourceFitPCM (pcm, source, &options, maskVal, markVal, psfSize);
+    ////   if (TIMING) {
+    ////        float *PAR = model->params->data.F32;
+    ////        fprintf (stderr, "%d %f : %f - %f %f %f - %f\n", model->nIter, model->chisqNorm, PAR[7], PAR[4], PAR[5], PAR[6], PAR[1]);
+    ////   }
+    //// }
+
+    // return to the original fitting mode (fitOptions)
+    pmPCMupdate(pcm, source, fitOptions, model);
+
+    psFree (chi2);
+    psFree (Sidx);
+    psFree (poly);
+
+    return true;
+}
+
+ 
+// we have a set of guess parameters, do a small number of iterations fitting only SHAPE then only INDEX 
+bool psphotFitSersicShapeAndIndexGrid (pmPCMdata *pcm, pmReadout *readout, pmSource *source, pmSourceFitOptions *fitOptions, psImageMaskType maskVal, psImageMaskType markVal, int psfSize) {
+
+    pmModel *model = pcm->modelConv;
+
+    assert (model->type == pmModelClassGetType("PS_MODEL_SERSIC"));
+
+    pmSourceFitOptions options = *fitOptions;
+    
+    psF32 *PAR = pcm->modelConv->params->data.F32;
+
+    options.mode = PM_SOURCE_FIT_SHAPE;
+    options.nIter = 10;
+    
+    // update the pcm elements if we have changed the circumstance (here, options.mode)
+    pmPCMupdate(pcm, source, &options, model);
+    
+    psVector *chi2 = psVectorAllocEmpty (16, PS_TYPE_F32);
+    psVector *Sidx = psVectorAllocEmpty (16, PS_TYPE_F32);
+
+    float par7[] = {0.100, 0.125, 0.150, 0.175, 0.200, 0.225, 0.250};
+    for (int i = 0; i < 7; i++) {
+      PAR[PM_PAR_7] = par7[i];
+      pmSourceFitPCM (pcm, source, &options, maskVal, markVal, psfSize);
+      if (EXTRA_VERBOSE) fprintf (stderr, "%d >>> %d %f : %f - %f %f - %f %f %f - %f\n", source->id, model->nIter, model->chisqNorm, PAR[7], PAR[2], PAR[3], PAR[4], PAR[5], PAR[6], PAR[1]);
+      psVectorAppend (Sidx, PAR[PM_PAR_7]);
+      psVectorAppend (chi2, model->chisqNorm);
+    }
+
+    psPolynomial1D *poly = psPolynomial1DAlloc (PS_POLYNOMIAL_ORD, 2);
+    if (!psVectorFitPolynomial1D (poly, NULL, 0, chi2, NULL, Sidx)) {
+      psError(PS_ERR_UNKNOWN, true, "Failed to find a good chisq parabola");
+      psFree (chi2);
+      psFree (Sidx);
+      psFree (poly);
+      return false;
+    }
+
+    // where is the minimum of this polynomial fit?
+    fprintf (stderr, "fit1d: %f + %f x + %f x^2\n", poly->coeff[0], poly->coeff[1], poly->coeff[2]);
+    float Smin = -0.5 * poly->coeff[1] / poly->coeff[2];
+
+    // constrain Smin to be in a valid range (1.0 - 0.1, corresponding to 0.5 (Gauss) to 5.0 (slightly peakier than Dev)
+    Smin = PS_MAX(PS_MIN(Smin, 1.0), 0.1);
+    PAR[PM_PAR_7] = Smin;
+    pmSourceFitPCM (pcm, source, &options, maskVal, markVal, psfSize);
+    if (EXTRA_VERBOSE) fprintf (stderr, "%d >>> %d %f : %f - %f %f - %f %f %f - %f\n", source->id, model->nIter, model->chisqNorm, PAR[7], PAR[2], PAR[3], PAR[4], PAR[5], PAR[6], PAR[1]);
+    
+    //// for (int i = 0; i < 8; i++) PAR[i] = parStart[i];
+    //// 
+    //// for (float fI = 0.0; fI < 0.15; fI += 0.01) {
+    ////   PAR[PM_PAR_7] = parStart[7] - fI;
+    //// 
+    ////   // fit EXT (not PSF) model (set/unset the pixel mask)
+    ////   
+    ////   pmSourceFitPCM (pcm, source, &options, maskVal, markVal, psfSize);
+    ////   if (TIMING) {
+    ////        float *PAR = model->params->data.F32;
+    ////        fprintf (stderr, "%d %f : %f - %f %f %f - %f\n", model->nIter, model->chisqNorm, PAR[7], PAR[4], PAR[5], PAR[6], PAR[1]);
+    ////   }
+    //// }
+
+    // return to the original fitting mode (fitOptions)
+    pmPCMupdate(pcm, source, fitOptions, model);
+
+    psFree (chi2);
+    psFree (Sidx);
+    psFree (poly);
+
+    return true;
+}
+
+