How to plot a linear piecewise function on matlab?

Can you please mark the error in the following code?

I'm facing the error:

>> linear

Linear Function:

Parameters: [1x1 struct]

X = 0:0.001:50 ;

f = double(X<20).* (0) + ...

double(and(X>=20,X<35)).* ((X-20)./15) + ...

double(X>=35).*(1);

g = double(X<20).* (1) + ...

double(and(X>=20,X<35)).* ((35-(X))./(15)) + ...

double(X>=35).*(0);

figure;

plot(X,f,'r','linewidth',2);

hold on ;

plot(X,g,'b','linewidth',2);

xlabel('X');

xticks(2:1:10);

[DGM]

The error message you pasted is not an error message. You called linear() and created a nonlinearity estimator object. The code you pasted does not produce any error messages, and it does not call any function called linear(), nor does it attempt to use any variable called linear. The manual call to linear() appears to be entirely unrelated to both the code and the task of creating a PWL plot, so I don't know why you're including it.

If the code does something that you don't want it to do, it's up to you to explain what you expect and how the results don't meet your expectations.

[Dyuman Joshi]

The code expect for the first line you mentioned runs without any error. I am not sure what the command linear supposed to do, nor do we have the data of linear to run to reproduce the error.

If you are getting an error, copy and paste the full error, which means all of the red text.

Also, there's no need of using double().

X = 0:0.001:50 ;
f = (X<20).* (0) + (and(X>=20,X<35)).* ((X-20)./15) + (X>=35).*(1);
g = (X<20).* (1) + (and(X>=20,X<35)).* ((35-(X))./(15)) + (X>=35).*(0);
figure; 
plot(X,f,'r','linewidth',2);
hold on ;
plot(X,g,'b','linewidth',2); 
xlabel('X');

%xticks(2:1:10); 

[DGM]

... or just

% all you need to define a polyline are the vertices
x = [0 20 35 50];
f = [0 0 1 1];
g = [1 1 0 0];

plot(x,f,'r','linewidth',2);
hold on ;
plot(x,g,'b','linewidth',2); 
xlabel('X');

Answer 1

[Sam Chak]

Might as well...

but this approach requires the fuzzy logic toolbox.

https://www.mathworks.com/help/fuzzy/linzmf.html

https://www.mathworks.com/help/fuzzy/linsmf.html

x = 0:0.1:50;
f = linsmf(x, [20 35]);     % s-shaped function
g = linzmf(x, [20 35]);     % z-shaped function
plot(x, [g; f]', 'linewidth', 2), grid on
xlabel('X');

[Amna Habib]

Thanks a lot @DGM @Dyuman Joshi @Sam Chak