How to create a periodic function?
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The function at [0,2] is y=x for [0,1] and y=2-x for [1,2], I want the above function repeated at [2,10], so I need a periodic funtion in the whole [0,10], who can help me code it ,thank you.
采纳的回答
James Tursa
2020-11-25
Not sure what you mean by "repeated at [2,10]". Maybe this:
y = mod(x,2);
ix = y > 1;
y(ix) = 2 - y(ix);
9 个评论
huazai2020
2020-11-25
Just like this
James Tursa
2020-11-25
Plot what I gave you ...
huazai2020
2020-11-25
Thank you, you give me the right code, but I cannot understand the code "y = mod(x,2);", could you please discribe it for me?
In addition, I want to use this one, could you help me revise it
James Tursa
2020-11-25
编辑：James Tursa
2020-11-25
Since you are making a periodic function, the mod(x,2) simply puts all of the input values into the range of one cycle. From there it is just a matter of forming the proper outputs of one cycle. The y=x part for the [0,1] input didn't need any adjustment so no extra code for that. Only the [1,2] part needed the extra code.
For this new function, you simply need to scale the x input properly and then use the same algorithm. E.g.,
y = mod(x/3,2);
ix = y > 1;
y(ix) = 2 - y(ix);
huazai2020
2020-11-25
Thank you are right，but where can find the define of “mod”.
In addition, how can I revise the amplitude to 0.2, how can I revise it?
James Tursa
2020-11-25
编辑：James Tursa
2020-11-25
To revise the amplitude, simply add one more line to the algorithm:
y = 0.2 * y;
The mod( ) function description can be found here:
huazai2020
2020-11-25
James Tursa
2020-11-25
Generic code could be:
% Periodic triangle wave
amplitude = whatever;
period = whatever;
y = mod(x,period);
ix = y > period/2;
y(ix) = period - y(ix);
y = (amplitude * 2 / period) * y;
huazai2020
2020-11-25
更多回答（2 个）
David Hill
2020-11-25
y=zeros(size(x));
for k=1:5
y(x>=(k-1)*2&x<(k-1)*2+1)=x(x>=(k-1)*2&x<(k-1)*2+1);
y(x>=2*(k-1)+1&x<2*k)=2-x(x>=2*(k-1)+1&x<2*k);
end
4 个评论
huazai2020
2020-11-25
Hi， thank you for your answer，but I find it is not the results that I want as you see in the image，
clc;
clear all;
x=linspace(0,10,100);
y=zeros(size(x));
for k=1:5
y(x>=(k-1)*2&x<(k-1)*2+1)=x(x>=(k-1)*2&x<(k-1)*2+1);
y(x>=2*(k-1)+1&x<2*k)=2-x(x>=2*(k-1)+1&x<2*k);
end
plot(x,y)
David Hill
2020-11-25
Are your functions changing? Recommend showing us the input and output you want.
Image Analyst
2020-11-25
Then just use the code that you used to create the figure. It's what you want isn't it?
huazai2020
2020-11-25
Setsuna Yuuki.
2020-11-25
You can use this function: https://es.mathworks.com/matlabcentral/fileexchange/83058-continuous-piecewise-function-linear-funcion-por-partes
x = [0:3:36];
y = [0 1 0 1 0 1 0 1 0 1 0 1 0];
sig = pwfun(x,y);
and create the waveform only with the intersection points.
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