필터 지우기
필터 지우기

how we can define piecewise function in matlab?

조회 수: 21 (최근 30일)
ebi
ebi 2013년 10월 12일
답변: shashi raj 2019년 10월 21일
in maple we can use comamnd:(
f:= piecewise(0 <= t and t <= T1, f1, T1 < t and t < T2, 0, T2 <=t and t <= T3, f1, T3 < t and t < T4, 0)
but in matlab i can not define this function.
please give me som information ...
thanks

채택된 답변

Sally Al Khamees
Sally Al Khamees 2016년 12월 23일
편집: Sally Al Khamees 2017년 2월 21일
If you have R2016b and the Symbolic Math Toolbox installed, you can just use the piecewise function:

추가 답변 (3개)

Walter Roberson
Walter Roberson 2013년 10월 12일
You cannot define that as a function in MATLAB. MATLAB functions need to have a defined value for the case where none of the conditions hold. If you were absolutely sure that one of the conditions will hold you would rewrite the Maple function without the final condition, as
piecewise(0 <= t and t <= T1, f1, T1 < t and t < T2, 0, T2 <=t and t <= T3, f1, 0)
This would be
function y = f(t, T1, T2, T3, f1)
y = zeros(size(t));
idx1 = 0 <= t & t <= T1;
y(idx1) = f1;
idx2 = T1 < t & t < T2;
y(idx2) = 0;
idx3 = T2 <= t & t <= T3;
y(idx3) = f1;
y(~(idx1 | idx2 | idx3)) = 0;
end
  댓글 수: 4
ebi
ebi 2013년 10월 12일
thanks a lot i will try it ...
Walter Roberson
Walter Roberson 2017년 2월 21일
Note: my later experiments showed that using sym('t->...') cannot possibly create a symbolic function.

댓글을 달려면 로그인하십시오.


sixwwwwww
sixwwwwww 2013년 10월 12일
Dear ebi, You need something like this if I understood correctly:
syms f f1
t = input('Enter value of t: ');
% Assuming values of T1, T2 and T3 as follows
T1 = 10;
T2 = 20;
T3 = 30;
if ((t >= 0 && t <= T1) || (t >= T2 && t <= T3))
f = f1; % here you can define f1 as you wish
else
f = 0;
end
Is it ok?
  댓글 수: 3
sixwwwwww
sixwwwwww 2013년 10월 12일
Do you input 't' as a time vector? and get f(t) for which you can calculate fft? Is it right?
ebi
ebi 2013년 10월 13일
i plot f(t) from [0..0.336]s and for that time period i have to calculate the integral of (f(t).exp(-i.w.t)dt)=F(w) and then plot F - w .

댓글을 달려면 로그인하십시오.


shashi raj
shashi raj 2019년 10월 21일

카테고리

Help CenterFile Exchange에서 Assumptions에 대해 자세히 알아보기

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by