Index: trunk/psphot/src/psModulesUtils.c
===================================================================
--- trunk/psphot/src/psModulesUtils.c	(revision 5828)
+++ trunk/psphot/src/psModulesUtils.c	(revision 5993)
@@ -123,2 +123,41 @@
     return (new);
 }
+
+float pmSourceCrossProduct (pmSource *Mi, pmSource *Mj) {
+
+    int Xs, Xe, Ys, Ye;
+    int xi, xj, yi, yj;
+    int xIs, xJs, yIs, yJs;
+    int xIe, yIe;
+    float flux;
+
+    psImage *Pi = Mi->pixels;
+    psImage *Pj = Mj->pixels;
+
+    psImage *Ti = Mi->mask;
+    psImage *Tj = Mj->mask;
+
+    Xs = PS_MAX (Pi->col0, Pj->col0);
+    Xe = PS_MIN (Pi->col0 + Pi->numCols, Pj->col0 + Pj->numCols);
+    
+    Ys = PS_MAX (Pi->row0, Pj->row0);
+    Ye = PS_MIN (Pi->row0 + Pi->numRows, Pj->row0 + Pj->numRows);
+    
+    xIs = Xs - Pi->col0;
+    xJs = Xs - Pj->col0;
+    yIs = Ys - Pi->row0;
+    yJs = Ys - Pj->row0;
+
+    xIe = Xe - Pi->col0;
+    yIe = Ye - Pi->row0;
+
+    flux = 0;
+    for (yi = yIs, yj = yJs; yi < yIe; yi++, yj++) {
+	for (xi = xIs, xj = xJs; xi < xIe; xi++, xj++) {
+	    if (Ti->data.U8[yi][xi]) continue;
+	    if (Tj->data.U8[yj][xj]) continue;
+	    flux += Pi->data.F32[yi][xi] * Pj->data.F32[yj][xj];
+	}
+    }
+    return (flux);
+}