--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tvii/error.py	Sun Dec 17 13:22:44 2017 -0800
@@ -0,0 +1,12 @@
+import numpy as np
+
+def error(function, x, y):
+    """
+    computes true value and error and returns
+    them both as a 2-tuple
+    """
+
+    yhat = np.array([function(*val) for val in x])
+    error = yhat - np.array(y)
+
+    return (yhat, error)