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Re: loops vs vectorization
From: |
Robert A.Macy |
Subject: |
Re: loops vs vectorization |
Date: |
Wed, 05 Jul 2006 17:46:21 -0700 |
On Wed, 5 Jul 2006 18:20:40 -0500
"Ozzy Lash" <address@hidden> wrote:
> On 7/5/06, Robert A.Macy <address@hidden> wrote:
> > Would somebody be kind enough to refresh my memory how
> to
> > avoid a "for" loop when there are a lot of conditional
> > adjustments going on?
> >
> > for example, the simple act of replacing every item
> that is
> > less than negative with the value zero.
> >
> > Can't remember all the nuances on writing 'vectorized'
> > versions of those types of conversions.
> >
> > - Robert -
> >
> One way to do what you ask is:
>
> octave:6> A=rand(5)-0.5
> A =
>
> 0.172279 0.035958 0.236123 0.472645 0.278473
> -0.143212 -0.459838 0.450752 0.460015 -0.332292
> 0.126755 -0.047737 0.044301 0.338564 -0.118386
> -0.245099 -0.466291 -0.498579 0.164236 -0.155360
> -0.252265 0.239568 -0.298967 0.435878 -0.153951
>
> octave:7> A(A<0)=0
> A =
>
> 0.17228 0.03596 0.23612 0.47265 0.27847
> 0.00000 0.00000 0.45075 0.46002 0.00000
> 0.12675 0.00000 0.04430 0.33856 0.00000
> 0.00000 0.00000 0.00000 0.16424 0.00000
> 0.00000 0.23957 0.00000 0.43588 0.00000
>
> octave:8>
Thanks, that's it? All these years...doing for loops
you say 'one way' are there others?
so how to do 'if, else' without doing two statements in a
row?
- Robert -
- Re: profiler and/or debugger, loops vs vectorization, (continued)
- Re: profiler and/or debugger, loops vs vectorization, David Grohmann, 2006/07/05
- Re: profiler and/or debugger, loops vs vectorization, David Bateman, 2006/07/05
- Re: profiler and/or debugger, loops vs vectorization, John W. Eaton, 2006/07/05
- Re: profiler and/or debugger, loops vs vectorization, Andy Adler, 2006/07/05
- Re: profiler and/or debugger, loops vs vectorization, David Grohmann, 2006/07/05
- Message not available
- Re: profiler and/or debugger, loops vs vectorization, Jordi Gutierrez Hermoso, 2006/07/05
- Re: loops vs vectorization, Robert A.Macy, 2006/07/05
- Re: loops vs vectorization, Rafael Almeida, 2006/07/05
- Re: loops vs vectorization, Robert A.Macy, 2006/07/05
- Re: loops vs vectorization, Ozzy Lash, 2006/07/05
- Re: loops vs vectorization,
Robert A.Macy <=
- Re: loops vs vectorization, Ozzy Lash, 2006/07/06
- Re: loops vs vectorization, Joan Picanyol i Puig, 2006/07/06
- Re: loops vs vectorization, Paul Kienzle, 2006/07/06
- Re: loops vs vectorization, Joan Picanyol i Puig, 2006/07/07
- Tics, Graupner, Achim Dr., 2006/07/07
- Re: profiler and/or debugger, loops vs vectorization, Michael Creel, 2006/07/06
- Re: profiler and/or debugger, loops vs vectorization, Javier Fernández Baldomero, 2006/07/06