Persistent Variable in a Function
显示 更早的评论
Hi,
I'm having difficulty writing code for a persistent variable. The goal is to have a value either be 1 or 0, depending on velocity. If velocity goes under 5 m/s, the function "turns on", effectively adding the component of the equation it is attached to, for 10 seconds. After that 10 seconds, it should automatically be reset to zero to "turn off" that particular part of the equation. Here is the equation in the script:
F = @(v,t) -((b/mc)*v.^2)-(9.81)*sin(theta)+(Fg/mc)*abs(sin(freqg*t))-(Fb/mc)*abs(sin(freqb*t))+(Fr/mc)*Rect(v,t);
Rect(v,t) is the function containing the persistent variable, and here is what I have so far:
function [ j ] = Rect( v,t )
if Check(v)<5
for t=t:1:t+10
j=1;
end
else
j=0;
end
end
I'm having difficulty wrapping my head around how to code it to behave how I would like it to. Any help is appreciated, thank you!
2 个评论
dpb
2015-3-19
What is Check intended to be? It's undefined in the function unless it's a GLOBAL (ugly!).
Josh Cheng
2015-3-19
采纳的回答
Most likely, you would be better off without that Rect subfunction and instead use a variable to track the state of that Rect inside the loop that calls F.
Failing that, the following Rect would work:
function state = Rect(v, t)
persistent triggertime;
if v < 5
%add t to the list of trigger times
triggertime = [triggertime t]; %#ok<AGROW>
end
state = any(t >= triggertime & t < triggertime + 10);
end
更多回答（0 个）
类别
在 帮助中心 和 File Exchange 中查找有关 Spectral Measurements 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
