Changeset 28659 for branches/eam_branches/ipp-20100621/ppSim/src/ppSimMakeGalaxies.c

Timestamp:

Jul 11, 2010, 3:24:33 PM (16 years ago)

Author:

eugene

Message:

sersic model consistency

File:

• branches/eam_branches/ipp-20100621/ppSim/src/ppSimMakeGalaxies.c (modified) (2 diffs)

branches/eam_branches/ipp-20100621/ppSim/src/ppSimMakeGalaxies.c

@@ -96 +96 @@
                 galaxy->y    = iy;
 
-                galaxy->peak = 20000;
+                galaxy->peak = 1000;
 
-                galaxy->index = (galaxyIndexMin  + i * galaxyIndexSlope);
-                galaxy->Rmaj  = (galaxyRmajorMin + i * galaxyRmajorSlope);
+                // galaxyIndex from user should be for function of this form: exp(-r^(1/n))
+                // galaxy->index = (1/2n)
+
+                float index = (galaxyIndexMin  + i * galaxyIndexSlope); // factor of 0.5 because the Sersic model creates exp(-z^n), not exp(-r^n)
+                galaxy->index = 0.5/index;
+
+                float scale = (galaxyRmajorMin + i * galaxyRmajorSlope);
+
+                // for a sersic model, 
+                float bn = 1.9992*index - 0.3271;
+                float fR = 1.0 / (sqrt(2.0) * pow (bn, index));
+                float Io = exp(bn);
+
+                // galaxy->Rmaj  = scale * fR;
+
+                galaxy->Rmaj  = scale;
                 galaxy->Rmin  = (galaxyARatioMin + i * galaxyARatioSlope) * galaxy->Rmaj;
                 galaxy->theta = (galaxyThetaMin  + i * galaxyThetaSlope);
+
+                // galaxy->peak *= Io;
+
+                fprintf (stderr, "Rmaj: %f, scale: %f, index: %f, bn: %f, Ro: %f, Io: %f\n",
+                         galaxy->Rmaj, scale, index, bn, fR, Io);
 
                 psArrayAdd (galaxies, 100, galaxy);
@@ -124 +143 @@
             galaxy->y    = psRandomUniform(rng) * ySize; // y position
 
-            galaxy->flux = pow ((double)((i + 1) / norm), (double) (1.0 / galaxyLum));
+            // galaxy->flux = pow ((double)((i + 1) / norm), (double) (1.0 / galaxyLum));
 
-            galaxy->index = (psRandomUniform(rng) * galaxyIndexSlope  + galaxyIndexMin);
+            galaxy->index = (sqrt(psRandomUniform(rng)) * galaxyIndexSlope  + galaxyIndexMin);
             galaxy->theta = (psRandomUniform(rng) * galaxyThetaSlope  + galaxyThetaMin);
             galaxy->Rmaj  = (psRandomUniform(rng) * galaxyRmajorSlope + galaxyRmajorMin);
-            galaxy->Rmin  = (psRandomUniform(rng) * galaxyARatioSlope + galaxyARatioMin) * galaxy->Rmaj;
+            galaxy->Rmin  = (PS_SQR(psRandomUniform(rng)) * galaxyARatioSlope + galaxyARatioMin) * galaxy->Rmaj;
 
+            // the flux is only approximately correct (scaling of the peak is wrong)
+            // elsewhere (ppSimInsertGalaxies.c) we calculate the true galaxy flux
             galaxy->flux = expf((logf(i + 1) - logf(norm)) / galaxyLum); // Peak flux
             galaxy->peak = galaxy->flux / (2.0*M_PI*PS_SQR(seeing));
-            // galaxy->peak = 5000;
 
             psArrayAdd (galaxies, 100, galaxy);