[Matrix-SIG] Numeric Nits

[Scott M. Ransom]

Tim Hochberg wrote:

> Second, two static functions could be added to Numeric to set the precision
> of Scalar values. By default, floats would be converted to type 'd' when
> they are converted to zero-d arrays, as they are now, but a call to:
> 
> >>> Numeric.setFloatPrecision('f')
> 
> ......

Is there a way to make this a more general solution when working with
Numeric?  To change the casting rules as a whole -- instead of just for
zero-d arrays?  Or would this not be possible (i.e. since it goes
against the core Python rules).

As another astronomer trying to wean myself from IDL, I have to agree
with Rick and Perry that the memory use/efficiency issues with Numeric
are quite important.  I frequently deal with _huge_ (~10**8 point) 1-D
time series (I am using a parallelized version of Python on an IBM SP2
among others), all of which are single precision float or single
precision complex.

I am currently working around the upcasts by using a few 'C' routines to
perform some simple vector math and/or casting.  So my code would
certainly be amongst the rare bits that would be broken by changes to
the casting or precision rules.  But I would actually really like to see
such changes.

I completely agree that an ugly solution will turn away substantial
numbers of scientific users -- something that I don't believe is good
for any of us.  With Tim's proposal, should it be possible to extend it
to all numeric arrays, we could keep the majority of legacy code
un-broken and still allow those of us working with un-gainly sized
arrays the opportunity to prod and poke at our data sets interactively
instead of making us run back to good-ole-'C'.

Scott

-- 
Scott M. Ransom                   
Phone:  (781) 320-9867             Address:  75 Sanderson Ave.
email:  ransom@cfa.harvard.edu               Dedham, MA  02026
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