Changeset 36198 for branches/eam_branches/ipp-20130904/psphot/src/psphotPetrosianStats.c

Timestamp:

Oct 9, 2013, 4:14:19 PM (13 years ago)

Author:

eugene

Message:

merge from trunk

Location:

branches/eam_branches/ipp-20130904/psphot

Files:

• . (modified) (1 prop)
• src (modified) (1 prop)
• src/psphotPetrosianStats.c (modified) (4 diffs)

branches/eam_branches/ipp-20130904/psphot/src/psphotPetrosianStats.c

@@ -6 +6 @@
 // generate the Petrosian radius and flux from the mean surface brightness (r_i)
 
+float InterpolateValuesQuadratic (float *Xin, float *Yin, float X);
 float InterpolateValues     (float X0, float Y0, float X1, float Y1, float X);
 float InterpolateValuesErrX (float X0, float Y0, float X1, float Y1, float X, float dX0, float dX1);
@@ -53 +54 @@
     float dFsum2 = 0.0;
 
-    float nSigma = 3.0;
+    float nSigma = 2.0;
     int lowestSignificantRadius = 0;
     float lowestSignificantRatio = 1.0;
@@ -118 +119 @@
                 petRadiusErr = InterpolateValuesErrX (1.0, 0.0, petRatio->data.F32[nOut], refRadius->data.F32[nOut], PETROSIAN_RATIO, 0.0, petRatioErr->data.F32[nOut]);
             } else {
-                petRadius    = InterpolateValues     (petRatio->data.F32[nOut-1], refRadius->data.F32[nOut-1], petRatio->data.F32[nOut], refRadius->data.F32[nOut], PETROSIAN_RATIO);
-                petRadiusErr = InterpolateValuesErrX (petRatio->data.F32[nOut-1], refRadius->data.F32[nOut-1], petRatio->data.F32[nOut], refRadius->data.F32[nOut], PETROSIAN_RATIO, petRatioErr->data.F32[nOut-1], petRatioErr->data.F32[nOut]);
+              // petRadius    = InterpolateValues     (petRatio->data.F32[nOut-1], refRadius->data.F32[nOut-1], petRatio->data.F32[nOut], refRadius->data.F32[nOut], PETROSIAN_RATIO);
+              if (nOut > 1) {
+                petRadius    = InterpolateValuesQuadratic (&petRatio->data.F32[nOut-2],   &refRadius->data.F32[nOut-2],   PETROSIAN_RATIO);
+              } else {
+                petRadius    = InterpolateValuesQuadratic (&petRatio->data.F32[nOut-3], &refRadius->data.F32[nOut-3], PETROSIAN_RATIO);
+              }
+              float petRadiusLinear = InterpolateValues     (petRatio->data.F32[nOut-1], refRadius->data.F32[nOut-1], petRatio->data.F32[nOut], refRadius->data.F32[nOut], PETROSIAN_RATIO);
+              if (fabs(petRadius - petRadiusLinear) > fabs(refRadius->data.F32[nOut] - refRadius->data.F32[nOut-1])) { 
+                fprintf (stderr, "big difference : %f vs %f\n", petRadius, petRadiusLinear); 
+              }
+              petRadiusErr = InterpolateValuesErrX (petRatio->data.F32[nOut-1], refRadius->data.F32[nOut-1], petRatio->data.F32[nOut], refRadius->data.F32[nOut], PETROSIAN_RATIO, petRatioErr->data.F32[nOut-1], petRatioErr->data.F32[nOut]);
             }
             above = false;
@@ -235 +245 @@
 }
 
+// Lagrange's form of the interpolating polynomial...
+float InterpolateValuesQuadratic (float *Xin, float *Yin, float X) {
+
+  float dx01 = Xin[0] - Xin[1];
+  float dx02 = Xin[0] - Xin[2];
+  float dx12 = Xin[1] - Xin[2];
+
+  float dx0  = X - Xin[0];
+  float dx1  = X - Xin[1];
+  float dx2  = X - Xin[2];
+
+  float y0 = Yin[0]*dx1*dx2/(dx01*dx02);
+  float y1 = Yin[1]*dx0*dx2/(dx01*dx12); // need - sign
+  float y2 = Yin[2]*dx0*dx1/(dx02*dx12); 
+
+  float Y = y0 - y1 + y2;
+  return Y;
+}
+
 float InterpolateValues (float X0, float Y0, float X1, float Y1, float X) {
     float dydx = (Y1 - Y0) / (X1 - X0);