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Re: Help: how to do ? [message #15277 is a reply to message #15269]

Tue, 04 May 1999 00:00

Robert S. Hill
Messages: 11
Registered: January 1998

Junior Member

On Tue, 4 May 1999, Pavel Romashkin wrote:

> Hi Tri,
> Now I tested it better. Try the following:
>

I added the following method to Pavel's test program:

start=systime(1)
a1=findgen(1,3)
a2=findgen(n,3)
a3 = make_array(n,val=1) # a1
a4 = a2 + a3
print, systime(1) - start
print, a4

I can't remember where I ran across this trick of using a matrix multiply
operation to replicate rows or columns. In any case, it's about the same
speed as Pavel's method (using the reform function) for small values of N,
but on my system takes about 0.6 the time of Pavel's method for n=100000
or more. How it depends on the Y dimension, I haven't checked.

Bob Hill

--
Robert.S.Hill.1@gsfc.nasa.gov Phone: 301-286-3624
Raytheon ITSS / Code 681, NASA/GSFC, Greenbelt, MD 20771

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[Message index]

		Re: Help: how to do ? By: eddie haskell on Tue, 04 May 1999 00:00
		Re: Help: how to do ? By: Pavel Romashkin on Tue, 04 May 1999 00:00
		Re: Help: how to do ? By: VU KHAC Tri on Tue, 04 May 1999 00:00
		Re: Help: how to do ? By: Robert S. Hill on Tue, 04 May 1999 00:00
		Re: Help: how to do ? By: Pavel Romashkin on Tue, 04 May 1999 00:00
		Re: Help: how to do ? By: Pavel Romashkin on Tue, 04 May 1999 00:00
		Re: Help: how to do ? By: Pavel Romashkin on Tue, 04 May 1999 00:00

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