How to plot function

2 visualizzazioni (ultimi 30 giorni)
Hardik
Hardik il 29 Lug 2014
Commentato: Ben11 il 30 Lug 2014
I'm working on a question where I am executing a function y = staircase(x) where
y = [ 0 if x <= 1 , 1 for 1<x<=2 & 2 if 2<x ]
So far I have;
function y = staircase(x)
for x = -3:0.01:3
if x <= 1
y = 0;
elseif x > 1 && x <= 2
y = 1;
else x > 2;
y = 2;
end
end
My question is how do I plot such a function?

Risposte (3)

Ben11
Ben11 il 29 Lug 2014
A lazy way would be like this:
figure
hold on
plot((-3:0.01:1),0,(1.01:0.01:2),1,(2.01:0.01:3),2,'LineWidth',2)
line('XData',[1 1],'YData',[0 1],'LineStyle',':');
line('XData',[2 2],'YData',[1 2],'LineStyle',':');
hold off
which gives this:
Do you need to write the plotting part in your function or you simply want to look at the staircase for some other purpose?

Azzi Abdelmalek
Azzi Abdelmalek il 29 Lug 2014
Modificato: Azzi Abdelmalek il 29 Lug 2014
x is an input argument, you can't assign values to x inside the function.
save this function as staircase.m
function y = staircase(x)
for k=1:numel(x)
if x (k)<= 1
y(k) = 0;
elseif x(k) > 1 && x(k) <= 2
y(k) = 1;
else x(k) > 2
y(k)= 2;
end
end
Then in Matlab Windows Command or in a new script write
x=-3:0.1:3 ; %assign values to x
y = staircase(x);
plot(x,y)
  4 Commenti
Hardik
Hardik il 30 Lug 2014
When I run the script with the addition of the numel, matlab gives me an error saying Not enough input arguments.
Ben11
Ben11 il 30 Lug 2014
As Azzi suggested, you have to define x before you call staircase. I ran his code and it works well. Do the following:
1) Define x in the command window
x = -3:0.1:3;
2) Once this is done, you can then call staircase(x) and plot the result:
y = staircase(x);
plot(x,y)

Accedi per commentare.


Star Strider
Star Strider il 29 Lug 2014
I built my own staircase function, because I didn’t want to create a separate function file.
This is how I plotted it:
x = -3:0.01:3;
staircase = @(x) [(0*(x <= 1)) + (1*((x > 1) & (x <= 2))) + (2*(x > 2))];
sc = staircase(x);
figure(1)
plot(x, sc)
axis([xlim -0.5 2.5])
The axis call makes it visible over its range.

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