list comprehension return a list and sum over in loop

[KK Sasa]

Jussi Piitulainen於 2014年12月12日星期五UTC+8下午7時12分39秒寫道：
> 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?

This is just a probability of binary response. Not continuous one. Tau is a parameter and just have two in this case.