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*Subject*: Re: Can I de-loop?*From*: eddie haskell <haskell(at)see.signature.edu>*Date*: Thu, 15 Jul 1999 09:14:54 -0400*Newsgroups*: comp.lang.idl-pvwave*Organization*: Old Dominion Universityaruba*References*: <7mje9s$263$1@nnrp1.deja.com>*Xref*: news.doit.wisc.edu comp.lang.idl-pvwave:15685

I have a suggestion for the first of your quandries: > a) I am adding a constant amount K to several elements N of array A. > The elements Ni are not unique; if an Ni is repeated, I want to add it > to A each time. For instance, given > > A = [0,1,2] > N = [2,2,2] > K = 4 > > I want the result A = [0,1,14], not A = [0,1,6] IDL> A[min(N):max(N)] = A[min(N):max(N)] + K*histogram(N) IDL> print,A 0 1 14 This seems to be at least twice as fast as the loop with the time difference increasing as the number of elements in A and N increase, at least for the values I played around with ( up to 100,000 elements). You should check this thread later as I should point out that over 95% of my suggestions to this newsgroup do not end up helping the original question. Either my solution is too specific for the problem or someone else soon posts a better solution. I hope for the latter as I can also learn something that way. Cheers, eddie ----- ---- --- --- ---- --- -- --- --- -- -- - - - - |\ A G Edward Haskell |\ Center for Coastal Physical Oceanography |\ Old Dominion University, Norfolk VA 23529 |\ Voice 757.683.4816 Fax 757.683.5550 |\ e-mail haskell*ccpo.odu.edu ----- ---- --- ---- --- --- --- --- -- -- -- - - - -

**References**:**Can I de-loop?***From:*throop

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