Changeset 15884 for trunk/psModules/src/astrom/pmAstrometryUtils.c

Timestamp:

Dec 19, 2007, 8:57:05 AM (19 years ago)

Author:

eugene

Message:

substantial work on astrometry model tables

File:

• trunk/psModules/src/astrom/pmAstrometryUtils.c (modified) (2 diffs)

trunk/psModules/src/astrom/pmAstrometryUtils.c

@@ -7 +7 @@
  *  @author EAM, IfA
  *
- *  @version $Revision: 1.5 $ $Name: not supported by cvs2svn $
- *  @date $Date: 2007-10-09 19:27:04 $
+ *  @version $Revision: 1.6 $ $Name: not supported by cvs2svn $
+ *  @date $Date: 2007-12-19 18:57:05 $
  *
  *  Copyright 2006 Institute for Astronomy, University of Hawaii
@@ -129 +129 @@
 }
 
+// rotate a transformation L(x,y) by theta
+psPlaneTransform *psPlaneTransformRotate (psPlaneTransform *output, psPlaneTransform *input, double theta)
+{
+    // validate fit order
+    if (output == NULL) {
+        output = psPlaneTransformAlloc(input->x->nX, input->x->nY);
+    }
+
+    /* given the polynomial transformations:
+     *  L(x,y) = \sum_i \sum_j A_{i,j} x^i y^j and 
+     *  M(x,y) = \sum_i \sum_j B_{i,j} x^i y^j 
+     * we can rotate L,M to L',M' by applying the rotation matrix (c,s),(-s,c).
+     * the resulting terms of L and M are:
+     * A'_{i,j} = c A_{i,j} + s B_{i,j}
+     * B'_{i,j} = c B_{i,j} - s A_{i,j}
+     */
+
+    float cs = cos(theta);
+    float sn = sin(theta);
+
+    for (int i = 0; i <= input->x->nX; i++) {
+        for (int j = 0; j <= input->x->nY; j++) {
+            // XXX what about inconsistent x and y masking?
+            output->x->coeffMask[i][j] = input->x->coeffMask[i][j];
+            output->y->coeffMask[i][j] = input->y->coeffMask[i][j];
+            if (output->x->coeffMask[i][j]) {
+                output->x->coeff[i][j] = 0.0;
+                output->y->coeff[i][j] = 0.0;
+            } else {
+                output->x->coeff[i][j] = cs*input->x->coeff[i][j] + sn*input->y->coeff[i][j];
+                output->y->coeff[i][j] = cs*input->y->coeff[i][j] - sn*input->x->coeff[i][j];
+            }
+        }
+    }
+    return output;
+}
+
 // construct a psPlaneTransform which is the identify transformation
 psPlaneTransform *psPlaneTransformIdentity (int order)