CODEWITHSUNDEEP
matlab
user288231
user288231

Reputation: 993

Plot ramp function

I am trying to plot a ramp function in MATLAB. I have the following function for my ramp:

function [ y ] = ramp(x)
    y=zeros(size(x));
    y(x>=0)=linspace(0,x(end),length(x(x>=0)))
end

But, I want it to have a similiar effect as my step function

syms x
ezplot(5*heaviside(x-1), [-10, 10])

When I use this code:

 syms x
 ezplot(5*ramp(x-1), [-10, 10])

When I do (x-1) it seems to throw an error that it is impossible, may I ask for some modificaitons?:

Cannot prove '0 <= x - 1' literally. To test the statement mathematically,
use isAlways.

Upvotes: 0

Views: 9337

Answers (1)

user3717023
user3717023

Reputation:

Your step function plot works with a function of symbolic variable x. But ramp, the way you have written it, is a function that expects numerical input (a vector of x-values). This is why your attempt to pass a symbolic x to it fails. Here is a correct way to plot this function:

x = linspace(-10,10,100);
plot(x, 5*ramp(x-1))

Alternatively, you can rewrite ramp as a function of a symbolic variable: 

function  y  = symbramp(x)
    y = (x+abs(x))/2;
end

and plot it as you did with Heaviside:

syms x
ezplot(5*symbramp(x-1), [-10,10])

Upvotes: 1

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