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Re: list comprehension return a list and sum over in loop

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Jussi Piitulainen wrote:

> KK Sasa writes:
> 
>> def p(x,t,point,z,obs):
>>     d = x[0]
>>     tau = [0]+[x[1:point]]
>>     a = x[point:len(x)]
>>     at = sum(i*j for i, j in zip(a, t))
>>     nu = [exp(z[k]*(at-d)-sum(tau[k])) for k in xrange(point)]
>>     de = sum(nu, axis=0)
>>     probability = [nu[k]/de for k in xrange(point)]
>>     return probability[obs]
> 
> I must be blind, but this looks like computing a whole probability
> distribution and then throwing almost all of it away.
> 
> Can't this just return nu[obs]/de?
> 
> The expression for tau also seems weird to me. Isn't it equivalent to
> [0, x[1:point]], a two-element list with the second element a list?
> How can sum(tau[k]) work at all then, for any k > 1?

Also, after adding 

from numpy.random import seed

to the code I run into the next problem:

Traceback (most recent call last):
  File "hessian.py", line 34, in <module>
    re = [d2(x,t[k],2,z,1) for k in range_people]
  File "/home/petto/.local/lib/python2.7/site-packages/ad/__init__.py", line 
1114, in hess
    return func(xa, *args).hessian([xa])
  File "hessian.py", line 26, in p
    nu = [exp(z[k]*(at-d)-sum(tau[k])) for k in xrange(point)]
TypeError: 'int' object is not iterable

OP: Optimizations only make sense when you can start from a known-good base. 
You should sort out the logic of your problem (we probably can't help you 
with that), then fix the bugs in your code and only then revisit the "speed 
issue". 

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list comprehension return a list and sum over in loop KK Sasa <genwei007@gmail.com> - 2014-12-11 22:22 -0800
  Re: list comprehension return a list and sum over in loop Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-12-12 07:17 +0000
    Re: list comprehension return a list and sum over in loop KK Sasa <genwei007@gmail.com> - 2014-12-12 00:30 -0800
      Re: list comprehension return a list and sum over in loop Christian Gollwitzer <auriocus@gmx.de> - 2014-12-12 10:09 +0100
      Re: list comprehension return a list and sum over in loop Peter Otten <__peter__@web.de> - 2014-12-12 10:13 +0100
        Re: list comprehension return a list and sum over in loop KK Sasa <genwei007@gmail.com> - 2014-12-12 01:45 -0800
          Re: list comprehension return a list and sum over in loop Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2014-12-12 13:12 +0200
            Re: list comprehension return a list and sum over in loop Peter Otten <__peter__@web.de> - 2014-12-12 13:32 +0100
              Re: list comprehension return a list and sum over in loop KK Sasa <genwei007@gmail.com> - 2014-12-12 05:09 -0800
                Re: list comprehension return a list and sum over in loop Peter Otten <__peter__@web.de> - 2014-12-12 17:08 +0100
                Re: list comprehension return a list and sum over in loop KK Sasa <genwei007@gmail.com> - 2014-12-12 19:04 -0800
                Re: list comprehension return a list and sum over in loop Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-12-13 11:27 +0000
            Re: list comprehension return a list and sum over in loop KK Sasa <genwei007@gmail.com> - 2014-12-12 05:03 -0800
  Re: list comprehension return a list and sum over in loop Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-12 20:46 +1100
  Re: list comprehension return a list and sum over in loop Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2014-12-12 16:47 +0000
  Re: list comprehension return a list and sum over in loop pecore@pascolo.net - 2014-12-13 13:38 +0100

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