Re: Setting Negatives to Zero
- To: mathgroup at smc.vnet.net
- Subject: [mg82821] Re: Setting Negatives to Zero
- From: "Kevin J. McCann" <Kevin.McCann at umbc.edu>
- Date: Wed, 31 Oct 2007 06:24:32 -0500 (EST)
- Organization: University System of Maryland
- References: <fg6qha$dj0$1@smc.vnet.net> <fg7287$jv9$1@smc.vnet.net>
Thanks Steve,
I knew I would feel stupid when I say the answer.
Unfortunately, though, when this is applied to my 63465 x 583 matrix it
takes over 69sec to execute. That other language can do it in less than
1 second! The difference must be that this technique is a pattern
matching? Not sure.
As an aside, I did a timing test on reading the data in in the first
place. Timing[] reports 2.7s (approx), but my watch says 20s. Not sure
what the difference is due to.
Thanks again,
Kevin
Steve Luttrell wrote:
> These do the sort of thing you want
>
> {1, 2, -3, -4, 5, 6} /. {_?(# < 0 &) -> 0}
>
> {1, 2, -3, -4, 5, 6} /. {_?NonPositive -> 0}
>
> and both give
>
>
--
Kevin J. McCann
Research Associate Professor
JCET/Physics
Physics Building
University of Maryland, Baltimore County
1000 Hilltop Circle
Baltimore, MD 21250