ValueError: math domain error #2

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1. jpvanhal commented on May 17, 2013

   

   jpvanhal

   on May 17, 2013

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   It seems that var_cr + var_crc is negative in your case, which causes sqrt to raise ValueError. I don't know how this is possible since both var_cr and var_crc should always be positive. Can you check what are the values of cr, crc, n and nc variables in z_score property, when this error is raised?
2. arg0s commented on May 17, 2013

   

   arg0s

   on May 17, 2013

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   Here you go. Let me know if you need more details.

   >>> cr = 0.0
   >>> crc = 10.3333333333
   >>> n = 3
   >>> nc = 3
   >>> 
   >>> mean = cr-crc
   >>> var_cr = cr * (1 - cr) / float(n)
   >>> var_crc = crc * (1 - crc) / float(nc)
   >>> var_cr
   0.0
   >>> var_crc
   -32.14814814792963
   >>> 
   
3. jpvanhal commented on May 18, 2013

   

   jpvanhal

   on May 18, 2013

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   The problem seems to be that your control alternative has more completions (31) than participations (3), which leads to crc not being between 0 and 1. I guess the reason for that is that finished() does not somehow mark the experiment as finished or the session is not saved after being modified.

   I would appreciate if you could either debug finished() and check if the experiment is properly being saved to the 'split_finished' in session, or provide a minimal code that introduces this bug.
4. arg0s commented on May 18, 2013

   

   arg0s

   on May 18, 2013

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   Hmm OK. Does the module take care of ensuring repeat calls to finish don't
   inflate the counts or do these need to be managed so they match the ab
   calls? Users may be refreshing the finish page.
   On May 18, 2013 1:23 PM, "Janne Vanhala" notifications@github.com wrote:

   The problem seems to be that your control alternative has more completions
   (31) than participations (3), which leads to crc not being between 0 and

   1. I guess the reason for that is that finished() does not somehow mark
      the experiment as finished or the session is not saved after being
      modified.

   I would appreciate if you could either debug finished() and check if the
   experiment is properly being saved to the 'split_finished' in session, or
   provide a minimal code that introduces this bug.

   —
   Reply to this email directly or view it on GitHubhttps://github.com//issues/2#issuecomment-18096807
   .
5. jpvanhal commented on May 18, 2013

   

   jpvanhal

   on May 18, 2013

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   Yes, the module does take care that repeating calls to finish don't inflate the counts.
6. arg0s commented on May 18, 2013

   

   arg0s

   on May 18, 2013

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   Got it. If its fine can I have your IRC handle? I'll ping you when I'm home
   and we can figure this out.

   Arvi
   On May 18, 2013 1:45 PM, "Janne Vanhala" notifications@github.com wrote:

   Yes, the module does take care that repeating calls to finish don't
   inflate the counts.

   —
   Reply to this email directly or view it on GitHubhttps://github.com//issues/2#issuecomment-18097049
   .
7. NickWoodhams commented on Apr 28, 2015

   

   NickWoodhams

   on Apr 28, 2015

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   Still have this error in some circumstances. Appears the user conversion tracking may be screwing up the math. Did you solve previously?