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Re: cumulative function? [message #12248 is a reply to message #12236]

Fri, 24 July 1998 00:00

wonko
Messages: 22
Registered: March 1997

Junior Member

dschmidt@lanl.gov (David M. Schmidt) wrote:

> Anyone know of a fast (e.g. built-in) way to construct a cumulative
> vector from a given input vector?
>
> The slow way is:
>
> Given A(100)
> C=fltarr(100)
> C(0)=A(0)
> For i=1,99 do C(i)=C(i-1)+A(i)

You could use an index array:

index = indgen( 99 ) + 1
C(0) = A(0)
C(index) = C(index-1) + A(index)

Or the shift function:

C(99) = 0
C = shift( C, 1 ) + A ; or was it -1 ?

Alex
--
Alex Schuster Wonko@weird.cologne.de PGP Key available
alex@pet.mpin-koeln.mpg.de

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		Re: cumulative function? By: David Foster on Mon, 27 July 1998 00:00
		Re: cumulative function? By: wonko on Fri, 24 July 1998 00:00

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