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 From: Frank Palazzolo Subject: RE: Easy about Matrices Date: Mon, 18 Apr 2005 13:59:34 -0400

```This syntax works as well:

x = randn(1,1000);
x_positive = (x>=0);
x_negative = (x<0);

I'm not sure if it's any more efficient, but it seems it would be, since it
never needs to build an explicit index vector.

-Frank

-----Original Message-----
Sent: Monday, April 18, 2005 1:43 PM
To: Alvaro Aguilera

Alvaro Aguilera wrote:

> Hello,
>
> I want to plot the data inside a matrix, but with different colors for
> the negative and positve terms. I do this now by spliting the matrix
> into two (negative, positive) using a "for" loop, and I wonder if
> there is another better approach to do this.
>
> Any hint welcome :)
>
> Regards,
>  Alvaro.
>
I'm not completely sure if this is what you're looking for, but maybe
this example helps:

x = randn(1,1000);
x_positive = x(find(x>=0));
x_negative = x(find(x<0));

-Quentin

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