[Python-talk] reduction Q

[Lloyd Kvam]

Sorry about totally misunderstanding your original post.

On Thu, 2009-10-22 at 14:11 -0400, bruce.labitt at autoliv.com wrote:
> 
> def compute_response( f, h ):
>         # a few calculations go here...
>         retval = [ Ph, Pv, Prec ]
>         return retval
> 
> for hr in hrlist:
>         arrays = (compute_response( freq, hr ) for freq in freqarray )
>         (sumh, sumv, sumP) = reduce( add, arrays ) 
>         dBh = 10.0*log10( sumh/ freqarray.size )
>         dBv = 10.0*log10( sumv/freqarray.size )
>         PdB = 10.0*log10( sumP/freqarray.size )
>         # more stuff...
> 
> The key was returning retval, rather than [Ph, Pv, Prec].  In this
> type of generator expression, one cannot return the tuple directly. 

Well retval is a list (square brackets).  There should be no difference
between returning the list and the name you've bound to the list.

If arrays is a sequence of lists, then reduce(add, arrays) should simply
flatten arrays into a single list.  Is that add the operator.add?

Obviously, I still do not have a clue.


(And I won't make it to the meeting, so you want have a chance to make
me more cluefull...)
-- 
Lloyd Kvam
Venix Corp.
1 Court Street, Suite 378
Lebanon, NH 03766-1358

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