diff --git a/examples/SodShock/makeIC.py b/examples/SodShock/makeIC.py
index a96aca432be50226521fa2572b71811e0e30cc1f..0ac0564116f8a6ceb57b4f41d23eb9907df0440d 100644
--- a/examples/SodShock/makeIC.py
+++ b/examples/SodShock/makeIC.py
@@ -87,7 +87,7 @@ u = append(u1, u2,0)
 m = append(m1, m2,0)
 ids = zeros(numPart, dtype='L')
 for i in range(1, numPart+1):
-    ids[i] = i
+    ids[i-1] = i
 
 #Final operations
 h /= 2