How to extract output from function

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Ali Najem
Ali Najem 2020-11-16
评论： Ali Najem 2020-11-18
Hello, All
i have this functions file
function [dydt,dE]=my(x,y)
f=(x^2-y^2)*sin(x);
dE=x^2;
dydt=10+f;
end
and this my run file
a=1; b=2; ya=1; m=40;
f=(@(t,y)my(t,y));
[t,y]=pure(f,a,b,ya,m);
I need to obtain dE from the function how can i proceed this
thanks indeed..
this is pure function file
function [ts,ys] = pure(f,a,b,y0,N)
t0 = a; T = b;
h = (T-t0)/N;
ts = zeros(N+1,1);
ys = zeros(1,length(y0));
t = t0;
yold = y0;
ts(1) = t;
ys(1,:) = yold';
for i=1:N
s1 = f(t,yold);
ynew = yold + s1*h;
yold=ynew;
t = t + h;
ts(i+1) = t; ys(1,:) = yold';
end
end

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采纳的回答

Stephen23
Stephen23 2020-11-16
Ran in:
To get De you could use arrayfun:
a=1;
b=2;
ya=1;
m=40;
[t,y]=pure(@my,a,b,ya,m)
t = 41×1
1.0000 1.0250 1.0500 1.0750 1.1000 1.1250 1.1500 1.1750 1.2000 1.2250
●
y = 3.7363
[~,dE] = arrayfun(@(tv)my(tv,y),t)
dE = 41×1
1.0000 1.0506 1.1025 1.1556 1.2100 1.2656 1.3225 1.3806 1.4400 1.5006
●
function [dydt,dE]=my(x,y)
f=(x^2-y^2)*sin(x);
dE=x^2;
dydt=10+f;
end
function [ts,ys] = pure(f,a,b,y0,N)
t0 = a; T = b;
h = (T-t0)/N;
ts = zeros(N+1,1);
ys = zeros(1,length(y0));
t = t0;
yold = y0;
ts(1) = t;
ys(1,:) = yold';
for i=1:N
s1 = f(t,yold);
ynew = yold + s1*h;
yold=ynew;
t = t + h;
ts(i+1) = t; ys(1,:) = yold';
end
end
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Stephen23
Stephen23 2020-11-17
This is how you defined the function my, with thirteen input arguments:
function [dy1dt,dE1,dE2,dE3,dE4] =my(input,batches,m,w1,b1,w3,b3,y0,u,errortot4,errortot2,grad4,grad2)
This is how you call the function my, with two input arguments:
my(tv,y)
If the function requires thirteen input arguments, then you need to call it with thirteen input arguments. You need to provide all of its required inputs, not just the first two.
https://www.mathworks.com/help/matlab/math/parameterizing-functions.html
Ali Najem
Ali Najem 2020-11-18
still got error am trying diffrent example same thing happening with me but with diffrent error
G=9.8; L=2;
tspan=[0 2*pi];
z0=[pi/3 0];
f=(@(t,y)my(t,y,G,L));
[t,y]=ode15s(f,tspan,z0);
[~,dE] = arrayfun(@(tv)mine(tv,y,G,L),t)
and this is the file of my function
function [dydt,dE]=my(t,y,G,L)
dydt = [y(2) ; -G/L*sin(y(1))];
dE=G*10;
end
when i run i got this error:-
Error using arrayfun
Non-scalar in Uniform output, at index 1, output 1.
Set 'UniformOutput' to false.
Error in run (line 18)
[r,dE] = arrayfun(@(tv)mine(tv,y,G,L),t)

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