Fix vulnerability to evaluating at points with 0.0

Author: cc7768

interpolation/complete_poly.py

@@ -358,7 +358,7 @@ def _complete_poly_der_impl_vec(z, d, der, out):
 
                 # Update index and out
                 ix += 1
-                out[ix] = c2 * t1*t2 * z[der]**(c2-1)
+                out[ix] = c2 * t1*t2 * z[der]**(c2-1) if c2>0 else 0.0
 
         return
 
@@ -369,12 +369,12 @@ def _complete_poly_der_impl_vec(z, d, der, out):
             for i2 in range(i1, nvar):
                 (c2, t2) = (c1+1, 1.0) if i2==der else (c1, z[i2])
                 ix += 1
-                out[ix] = c2 * t1*t2 * z[der]**(c2-1)
+                out[ix] = c2 * t1*t2 * z[der]**(c2-1) if c2>0 else 0.0
 
                 for i3 in range(i2, nvar):
                     (c3, t3) = (c2+1, 1.0) if i3==der else (c2, z[i3])
                     ix += 1
-                    out[ix] = c3 * t1*t2*t3 * z[der]**(c3-1)
+                    out[ix] = c3 * t1*t2*t3 * z[der]**(c3-1) if c3>0 else 0.0
 
         return
 
@@ -385,17 +385,17 @@ def _complete_poly_der_impl_vec(z, d, der, out):
             for i2 in range(i1, nvar):
                 (c2, t2) = (c1+1, 1.0) if i2==der else (c1, z[i2])
                 ix += 1
-                out[ix] = c2 * t1*t2* z[der]**(c2-1)
+                out[ix] = c2 * t1*t2* z[der]**(c2-1) if c2>0 else 0.0
 
                 for i3 in range(i2, nvar):
                     (c3, t3) = (c2+1, 1.0) if i3==der else (c2, z[i3])
                     ix += 1
-                    out[ix] = c3 * t1*t2*t3* z[der]**(c3-1)
+                    out[ix] = c3*t1*t2*t3*z[der]**(c3-1) if c3>0 else 0.0
 
                     for i4 in range(i3, nvar):
                         (c4, t4) = (c3+1, 1.0) if i4==der else (c3, z[i4])
                         ix += 1
-                        out[ix] = c4 * t1*t2*t3*t4 * z[der]**(c4-1)
+                        out[ix] = c4*t1*t2*t3*t4*z[der]**(c4-1) if c4>0 else 0.0
 
         return
 
@@ -406,22 +406,22 @@ def _complete_poly_der_impl_vec(z, d, der, out):
             for i2 in range(i1, nvar):
                 (c2, t2) = (c1+1, 1.0) if i2==der else (c1, z[i2])
                 ix += 1
-                out[ix] = c2 * t1*t2* z[der]**(c2-1)
+                out[ix] = c2 * t1*t2* z[der]**(c2-1) if c2>0 else 0.0
 
                 for i3 in range(i2, nvar):
                     (c3, t3) = (c2+1, 1.0) if i3==der else (c2, z[i3])
                     ix += 1
-                    out[ix] = c3 * t1*t2*t3* z[der]**(c3-1)
+                    out[ix] = c3 * t1*t2*t3* z[der]**(c3-1) if c3>0 else 0.0
 
                     for i4 in range(i3, nvar):
                         (c4, t4) = (c3+1, 1.0) if i4==der else (c3, z[i4])
                         ix += 1
-                        out[ix] = c4 * t1*t2*t3*t4 * z[der]**(c4-1)
+                        out[ix] = c4*t1*t2*t3*t4*z[der]**(c4-1) if c4>0 else 0.0
 
                         for i5 in range(i4, nvar):
                             (c5, t5) = (c4+1, 1.0) if i5==der else (c4, z[i5])
                             ix += 1
-                            out[ix] = c5 * t1*t2*t3*t4*t5 * z[der]**(c5-1)
+                            out[ix] = c5*t1*t2*t3*t4*t5*z[der]**(c5-1) if c5>0 else 0.0
 
         return
 
@@ -458,7 +458,7 @@ def _complete_poly_der_impl(z, d, der, out):
                 for k in range(nobs):
                     c1, t1 = (1, 1.0) if i1==der else (0, z[i1, k])
                     c2, t2 = (c1+1, 1.0) if i2==der else (c1, z[i2, k])
-                    out[ix, k] = c2 * t1*t2 * z[der, k]**(c2-1)
+                    out[ix, k] = c2*t1*t2*z[der, k]**(c2-1) if c2>0 else 0.0
 
         return
 
@@ -469,13 +469,13 @@ def _complete_poly_der_impl(z, d, der, out):
                 for k in range(nobs):
                     c1, t1 = (1, 1.0) if i1==der else (0, z[i1, k])
                     c2, t2 = (c1+1, 1.0) if i2==der else (c1, z[i2, k])
-                    out[ix, k] = c2 * t1*t2 * z[der, k]**(c2-1)
+                    out[ix, k] = c2*t1*t2*z[der, k]**(c2-1) if c2>0 else 0.0
 
                 for i3 in range(i2, nvar):
                     ix += 1
                     for k in range(nobs):
                         c3, t3 = (c2+1, 1.0) if i3==der else (c2, z[i3, k])
-                        out[ix, k] = c3 * t1*t2*t3 * z[der, k]**(c3-1)
+                        out[ix, k] = c3*t1*t2*t3*z[der, k]**(c3-1) if c3>0 else 0.0
 
         return
 
@@ -486,19 +486,19 @@ def _complete_poly_der_impl(z, d, der, out):
                 for k in range(nobs):
                     c1, t1 = (1, 1.0) if i1==der else (0, z[i1, k])
                     c2, t2 = (c1+1, 1.0) if i2==der else (c1, z[i2, k])
-                    out[ix, k] = c2 * t1*t2 * z[der, k]**(c2-1)
+                    out[ix, k] = c2*t1*t2*z[der, k]**(c2-1) if c2>0 else 0.0
 
                 for i3 in range(i2, nvar):
                     ix += 1
                     for k in range(nobs):
                         c3, t3 = (c2+1, 1.0) if i3==der else (c2, z[i3, k])
-                        out[ix, k] = c3 * t1*t2*t3 * z[der, k]**(c3-1)
+                        out[ix, k] = c3*t1*t2*t3*z[der, k]**(c3-1) if c3>0 else 0.0
 
                     for i4 in range(i3, nvar):
                         ix += 1
                         for k in range(nobs):
                             c4, t4 = (c3+1, 1.0) if i4==der else (c3, z[i4, k])
-                            out[ix, k] = c4 * t1*t2*t3*t4 * z[der, k]**(c4-1)
+                            out[ix, k] = c4*t1*t2*t3*t4*z[der, k]**(c4-1) if c4>0 else 0.0
 
         return
 
@@ -509,25 +509,25 @@ def _complete_poly_der_impl(z, d, der, out):
                 for k in range(nobs):
                     c1, t1 = (1, 1.0) if i1==der else (0, z[i1, k])
                     c2, t2 = (c1+1, 1.0) if i2==der else (c1, z[i2, k])
-                    out[ix, k] = c2 * t1*t2 * z[der, k]**(c2-1)
+                    out[ix, k] = c2*t1*t2*z[der, k]**(c2-1) if c2>0 else 0.0
 
                 for i3 in range(i2, nvar):
                     ix += 1
                     for k in range(nobs):
                         c3, t3 = (c2+1, 1.0) if i3==der else (c2, z[i3, k])
-                        out[ix, k] = c3 * t1*t2*t3 * z[der, k]**(c3-1)
+                        out[ix, k] = c3*t1*t2*t3*z[der, k]**(c3-1) if c3>0 else 0.0
 
                     for i4 in range(i3, nvar):
                         ix += 1
                         for k in range(nobs):
                             c4, t4 = (c3+1, 1.0) if i4==der else (c3, z[i4, k])
-                            out[ix, k] = c4 * t1*t2*t3*t4 * z[der, k]**(c4-1)
+                            out[ix, k] = c4*t1*t2*t3*t4*z[der, k]**(c4-1) if c4>0 else 0.0
 
                         for i5 in range(i4, nvar):
                             ix += 1
                             for k in range(nobs):
                                 c5, t5 = (c4+1, 1.0) if i5==der else (c4, z[i5, k])
-                                out[ix, k] = c5 * t1*t2*t3*t4*t5 * z[der, k]**(c5-1)
+                                out[ix, k] = c5*t1*t2*t3*t4*t5*z[der, k]**(c5-1) if c5>0 else 0.0
 
         return
 

interpolation/tests/test_complete.py

@@ -66,9 +66,11 @@ def test_complete_derivative():
     out_mat = complete_polynomial_der(z, 2, 1)
     assert(abs(out_mat[0, :]).max() < 1e-10)
     assert(abs(out_mat[2, :] - np.ones(2)).max() < 1e-10)
-    assert(abs(out_mat[-1, :] - np.array([5.0, 6.0])).max() < 1e-10)
+    assert(abs(out_mat[-2, :] - np.array([5.0, 6.0])).max() < 1e-10)
 
 
 if __name__ == '__main__':
     test_complete_scalar()
     test_complete_vector()
+    test_complete_derivative()
+