efficiency of UArray

[Simon Peyton-Jones]

GHC doesn't remove intermediate lists down both
branches of a zip, so yes, you'll get intermediate lists.

Why not use array indexing, as per your second version
(only in Haskell)?

Simon

| -----Original Message-----
| From: Hal Daume III [mailto:hdaume@ISI.EDU]=20
| Sent: 16 May 2002 00:55
| To: GHC Users Mailing List
| Subject: efficiency of UArray
|=20
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| can we expect a function like:
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|   sum [x*y | (x,y) <- zip (elems v) (elems u)]
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| to be as efficient as, say:
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| sum =3D 0
| for i=3D1, n
|   sum =3D sum + v[i] * u[i]
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| ?
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| Basically, will any intermediate lists be created here?
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| --
| Hal Daume III
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|  "Computer science is no more about computers    | hdaume@isi.edu
|   than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume
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