Index: trunk/psLib/src/math/psPolynomialUtils.c
===================================================================
--- trunk/psLib/src/math/psPolynomialUtils.c	(revision 10051)
+++ trunk/psLib/src/math/psPolynomialUtils.c	(revision 10593)
@@ -177,2 +177,36 @@
     return min;
 }
+
+# if (0)
+    psPolynomial2D *psPolynomial2D_dX (psPolynomial2D *poly)
+{
+
+    int nXout = poly->nX - 1;
+    int nYout = poly->nY;
+
+    psPolynomial2D *dX = psPolynomial2DAlloc (PS_POLYNOMIAL_ORD, nXout, nYout);
+
+    for (int i = 0; i < nXout; i++) {
+        for (int j = 0; j < nYout; j++) {
+            dX->mask[i][j] = poly->mask[i+1][j];
+            dX->coeff[i][j] = poly->coeff[i+1][j] * i+1;
+        }
+    }
+}
+
+psPolynomial2D *psPolynomial2D_dY (psPolynomial2D *poly)
+{
+
+    int nXout = poly->nX;
+    int nYout = poly->nY - 1;
+
+    psPolynomial2D *dX = psPolynomial2DAlloc (PS_POLYNOMIAL_ORD, nXout, nYout);
+
+    for (int i = 0; i < nXout; i++) {
+        for (int j = 0; j < nYout; j++) {
+            dX->mask[i][j] = poly->mask[i+1][j];
+            dX->coeff[i][j] = poly->coeff[i][j+1] * j+1;
+        }
+    }
+}
+#endif