Fix doc-tests for financial.py so they don't rely on floating-point exactness. Start filling in final function.

1 files changed, 4 insertions, 2 deletions

diff --git a/numpy/lib/financial.py b/numpy/lib/financial.py
index c5d6d27e7..5bb4a3af7 100644
--- a/numpy/lib/financial.py
+++ b/numpy/lib/financial.py
@@ -139,11 +139,13 @@ array([[[ 32.58497782,  38.57048452],
 """
 
 def ipmt(rate, per, nper, pv, fv=0.0, when='end'):
+    total = pmt(rate, nper, pv, fv, when)
+    # Now, compute the nth step in the amortization
     raise NotImplementedError
 
-
 def ppmt(rate, per, nper, pv, fv=0.0, when='end'):
-    raise NotImplementedError
+    total = pmt(rate, nper, pv, fv, when)
+    return total - ipmt(rate, per, nper, pv, fv, when)
 
 def pv(rate, nper, pmt, fv=0.0, when='end'):
     """Number of periods found by solving the equation