Testing evaluation at nodes

Added "node" property to LagrangePolynomialInterpolant
jeffrey-hokanson · Sep 9, 2020 · 9d1cec2 · 9d1cec2
1 parent 847f165
commit 9d1cec2
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diff --git a/polyrat/polynomial.py b/polyrat/polynomial.py
@@ -31,3 +31,7 @@ def __init__(self, X, y):
 
 	def roots(self, *args, **kwargs):
 		return self.basis.roots(self.coef, *args, **kwargs)	
+
+	@property
+	def nodes(self):
+		return self.basis.nodes
diff --git a/tests/test_lagrange.py b/tests/test_lagrange.py
@@ -56,6 +56,12 @@ def wilkinson(x):
 	print("relative error in evaluation", rel_err)
 	assert rel_err < 1e-10, "Error in evaluating Vandermonde matrix"
 
+	# Test evaluation on nodes
+	fX = lpi(lpi.nodes)
+	err = np.linalg.norm(lpi.coef - fX)
+	rel_err = err/np.linalg.norm(lpi.coef)
+	print("relative error in evaluation", rel_err)
+	assert rel_err < 1e-10, "Error in evaluating Vandermonde matrix"