Only calculate relative errors if a previous value exists.
authorW. Trevor King <wking@drexel.edu>
Fri, 2 Mar 2012 19:17:19 +0000 (14:17 -0500)
committerW. Trevor King <wking@drexel.edu>
Fri, 2 Mar 2012 19:17:19 +0000 (14:17 -0500)
commitee9d140813ea4a3419f7c12ae63e808ceb1ab8a1
treea7b7444513e88cafd3a1c4ae0b71238b28f79316
parent904f98c200a40abb6f86304c3ae912a01b9bac11
Only calculate relative errors if a previous value exists.

This avoids:

  TypeError: unsupported operand type(s) for -: 'float' and 'NoneType'
calibcant/analyze.py