how to plot a two-dimensional heaviside function

Question

Ksenia 2014-8-13

评论： Ksenia 2014-8-13

Hi, everybody! I'm trying to plot some heaviside function like that:

x=0:1000;
y=0:500;
z=0:25;
R=25*(heaviside(x-40)-heaviside(x-240))*(heaviside(y-40)-heaviside(y-160));

but I always get an error sound like

error using * Inner matrix dimensions must agree.

I was trying to rewrite an expression like this:

R=25*(heaviside(x-40)-heaviside(x-240)).*(heaviside(y-40)-heaviside(y-160));

but I've got the same mistake with using .*.... What can you suggest? And also how to plot functions like that?

Answer 1

Azzi Abdelmalek 2014-8-13

编辑：Azzi Abdelmalek 2014-8-13

x=0:1000;
y=0:500;
z=0:25;
a=25*(heaviside(x-40)-heaviside(x-240)),
b=(heaviside(y-40)-heaviside(y-160));
out=bsxfun(@times,a.',b)

Ksenia 2014-8-13

My first attempt was right. I've got a great plot by changing code like this:

[x,y]=meshgrid(0:30:1000, 0:30:500);
R=25*(heaviside(x-40)-heaviside(x-240)).*(heaviside(y-40)-heaviside(y-160));