Changeset 429

Timestamp:

02/14/05 17:33:53 (20 years ago)

Author:

kil064

Message:

add functions

getStokesSLice
circularPolarization

Location:

trunk/src

Files:

• SDPol.cc (modified) (5 diffs)
• SDPol.h (modified) (1 diff)

trunk/src/SDPol.cc

@@ -176 +176 @@
 // array of shape (nBeam,nIF,nPol,nChan)
 //
+// We use the scaling convention I=(XX+YY) 
+// 
 {
 
@@ -209 +211 @@
 //
    if (nPol==1) {
-      I = C1;
+      I = Float(2.0)*C1;
       return;
    }
@@ -217 +219 @@
    Array<Float> C2 = input2(start,end);          // Input : C1
 //
-   I = Float(0.5)*(C1 + C2);
+   I = C1 + C2;
    if (nPol <= 2) return;
 //
@@ -231 +233 @@
    end(polAxis) = 1;
    Array<Float> Q = output(start,end);           // Output : Q
-   Q = Float(0.5)*(C1 - C2);
+   Q = C1 - C2;
 //
    start(polAxis) = 2;
    end(polAxis) = 2;
    Array<Float> U = output(start,end);           // Output : U
-   U = C3;
+   U = Float(2.0)*C3;
 //
    start(polAxis) = 3;
    end(polAxis) = 3;
    Array<Float> V = output(start,end);           // Output : V
-   V = C4;
+   V = Float(2.0)*C4;
 }
 
@@ -311 +313 @@
 
 
+
+Array<Float> SDPolUtil::getStokesSlice (Array<Float>& in, const IPosition& start,
+                                        const IPosition& end, const String& stokes)
+{
+   IPosition s(start);
+   IPosition e(end);
+//
+   if (stokes=="I") {
+      s(asap::PolAxis) = 0;
+      e(asap::PolAxis) = 0;
+   } else if (stokes=="Q") {
+      s(asap::PolAxis) = 1;
+      e(asap::PolAxis) = 1;
+   } else if (stokes=="U") {
+      s(asap::PolAxis) = 2;
+      e(asap::PolAxis) = 2;
+   } else if (stokes=="V") {
+      s(asap::PolAxis) = 3;
+      e(asap::PolAxis) = 3;
+   }
+//
+   return in(s,e);
+}
  
+
+Array<Float> SDPolUtil::circularPolarizationFromStokes (Array<Float>& I,
+                                                        Array<Float>& V, 
+                                                        Bool doRR)
+{
+   if (doRR) {
+      return Float(0.5)*(I+V);
+   } else {
+      return Float(0.5)*(I-V);
+   }
+}
+

trunk/src/SDPol.h

@@ -53 +53 @@
                              casa::Array<casa::Float>& C4,
                              casa::Float phase);
+
+// Get Stokes slices from the Array.  Start and End should
+// already be setup to access the Array at the current cursor location
+// (beam, IF, chanells; see SDMemTable).  This function will modify the asap::PolAxis
+// location to access the desired Stokes slice ("I", "Q", "U", "V")
+  static casa::Array<casa::Float> getStokesSlice (casa::Array<casa::Float>& input, const casa::IPosition& start,
+                                                  const casa::IPosition& end, const casa::String& stokes);
+
+// Compute Circular polarization RR or LL from I and V
+  static casa::Array<casa::Float> circularPolarizationFromStokes (casa::Array<casa::Float>& I, 
+                                                                  casa::Array<casa::Float>& V, 
+                                                                  casa::Bool doRR);
 };