From e98e41f34c510d0fc52942df8cb11881a08467e6 Mon Sep 17 00:00:00 2001
From: Rowan Cockett <rowan@visiblegeology.com>
Date: Fri, 15 Nov 2013 10:10:10 -0800
Subject: [PATCH] dpred

---
 SimPEG/forward/Richards.py | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/SimPEG/forward/Richards.py b/SimPEG/forward/Richards.py
index d6d268be..780902ab 100644
--- a/SimPEG/forward/Richards.py
+++ b/SimPEG/forward/Richards.py
@@ -86,6 +86,20 @@ class RichardsProblem(Problem):
         self.doNewton = False  # This also sets the rootFinder algorithm.
         setKwargs(self, **kwargs)
 
+    def dpred(self, m, u=None):
+        """
+            Predicted data.
+
+            .. math::
+                d_\\text{pred} = Pu(m)
+        """
+        if u is None:
+            u = self.field(m)
+        u = np.concatenate(u[1:])
+        if self.dataType is 'saturation':
+            u = self.empirical.moistureContent(u)
+        return self.P*u
+
     def field(self, m):
         self.empirical.setModel(m)
         Hs = range(self.numIts+1)