Anonymous function or for loop?
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Assume I have a simple electrical function of V=C*sin(t) where C is a constant which varies based on t intervals.
I have used 2 methods to generate the C and by using tic/toc to check, Method 2 seems to be faster than Method 1.
For efficiency and speed wise, should I always use anonymous function instead of for loop? Or is my loop not being coded efficient enough?
t = 0 : 0.1 : 20;
c1 = 53; % (0 <= t <= 10)
c2 = 68; % (10 < t <= 20)
% Method 1 (For Loop)
tic
n = length(t);
a = ones(1,n);
for i = 1:n
if t(i)>=0 && t(i)<=10
A = c1;
else
A = c2;
end
a(i) = A;
end
toc
% Method 2 (Anonymous Function)
tic
C = @(t) (t>=0 & t<=10).*c1 + (t>10).*c2;
c = C(t);
toc
v = sin(t);
v2 = c.*v;
v3 = a.*v;
% Checking
a==c;
v2==v3;
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채택된 답변
KSSV
2021년 6월 24일
Off course, you can achieve the same without using anonymous function.
t = 0 : 0.1 : 20;
c1 = 53; % (0 <= t <= 10)
c2 = 68; % (10 < t <= 20)
tic
a = c1*ones(size(t)) ;
a(t>10) = c2 ;
toc
% Method 2 (Anonymous Function)
tic
C = @(t) (t>=0 & t<=10).*c1 + (t>10).*c2;
c = C(t);
toc
v = sin(t);
v3 = a.*v;
v4 = a.*v ;
% Checking
isequal(a,c)
isequal(v3,v4)
추가 답변 (2개)
Sulaymon Eshkabilov
2021년 6월 24일
Your second method is much faster. Try to avoid for or while loop if feasible.
At the same time, you may improve your 2nd method by computing the values of C directly for the predefined values of t, e.g:
% Method 2 (Anonymous Function)
t1 =0:0.1:10; t2 =10.01:.1:20; % t is split up into two ranges
tic
C =t1*c1 + t2*c2;
toc
v = sin(t);
v2 = C.*v;
v3 = a.*v;
% Checking
a==c;
v2==v3;
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