# Getting an error message when I use 'triangle()' function.

21 views (last 30 days)
Baris Dogan on 24 Mar 2024
Commented: Dyuman Joshi on 26 Mar 2024
I wrote a code to create a tiangle wave form for testing my functions as below:
close all; clearvars; clc;
t = 0:0.01:10*pi;
f = 5;
A = 10;
y = A * triangle(2*pi*t);
Unrecognized function or variable 'triangle'.
figure, plot(y);
But I am getting a Command Window error message as below:
Unrecognized function or variable 'triangle'.
Error in ucgenDalga (line 5)
y = A * triangle(2*pi*t);
I tested the code first in MATLAB 2022b and then in MATLAB Online, having the same error message. When I wrote "help triangle" in Command Window, MATLAB responds an answer. But when I use triangle function in my code, I am receiving the above error. I could not have got an answer from Internet search. Any idea is appreciated.
##### 3 CommentsShow 1 older commentHide 1 older comment
VBBV on 24 Mar 2024
The documentation states this function is for use in Stateflow estimation
Baris Dogan on 24 Mar 2024

Dyuman Joshi on 24 Mar 2024
Edited: Dyuman Joshi on 24 Mar 2024
That help is for a Stateflow operator in SIMULINK (as mentioned in the 1st line), not for a function in MATLAB.
help triangle
--- help for Stateflow operator triangle --- triangle - Triangle wave test signal triangle(x) generates a triangle wave from the input x based on the equation, Syntax triangle(x) Input Arguments x - Value during test step numeric scalar See also heaviside, ramp, sawtooth, square Introduced in Simulink Test in R2015a Documentation for triangle doc triangle
There is no MATLAB function named triangle (atleast not in the available toolboxes, as not all toolboxes are available in the live editor on MATLAB Answers)
which triangle -all
If you want to plot a triangle wave with a given amplitude and period, you can utilize mod -
A = 10;
p = 5;
y = @(x) A*mod(x,p)
y = function_handle with value:
@(x)A*mod(x,p)
fplot(y)
Baris Dogan on 25 Mar 2024
Thank you.
Dyuman Joshi on 26 Mar 2024

VBBV on 24 Mar 2024
Edited: VBBV on 24 Mar 2024
close all; clearvars; clc;
t = 0:0.01:10*pi;
f = 5;
A = 10;
y = A * sawtooth(2*pi*t);
figure, plot(t,y); xlim([0 2*pi])
##### 3 CommentsShow 1 older commentHide 1 older comment
Baris Dogan on 24 Mar 2024
Thank you for your answer. I also found sawtooth() in my search but I need a triangular (isosceles triangle) signal not a sawtooth (right triangle) signal. Anyway I assumed there may be a ready made function in MATLAB but it seems I need to write my own code.
VBBV on 24 Mar 2024
Edited: VBBV on 24 Mar 2024
You can modify your code using sawtooth in https://www.mathworks.com/help/signal/ref/sawtooth.html to suit what you want
close all; clearvars; clc;
t = 0:0.01:10*pi;
f = 5;
A = 10;
y = A * sawtooth(2*pi*t,1/2); % triangle wave with two equal sides
figure, plot(t,y); xlim([0 pi])

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