Calling function in fminsearch
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I want to call a function lamda to update initial value in fminsearch.
The initial value of lambda(1) =-1.
I want to update in lambda as lambda(i+1)=lambda(i)-0.01*(lambda(end)).
This computation of lambda should continue until lambda(end) < 0.01. I am not able to call function in fminsearch as FMINSEARCH accepts inputs only of data type double.
close all
clear all
clc
[optimal_lambda,cost] = fminsearch(@cost_lambda, @lamda)
a = optimal_lambda(1)
function cost = cost_lambda(lambda)
part_a = @(t,y)[-0.02*y(1); (y(2)/0.8)*(1/0.8)*exp(0.01*t)];
[t,y]=ode45(part_a, [0 10], [0.5,-1]');
cost = (1-(1/0.01)*(1-exp(-log((-1+(y(1)/0.8)^2)/(0.015*lambda(1)*exp(0.01*t)))))*(1-(y(1)/0.8))^2);
function lambda = lamda(lambda)
lambda(1)=-1;
i=1;
for lambda(end)<0.01
lambda(i+1)=lambda(i)-0.01*lambda(end)
i=i++
end
end
end
3 Commenti
Risposta accettata
Steven Lord
il 22 Ott 2022
If you mean you want to call fminsearch repeatedly with different initial points, call it in a loop.
f = @sin;
initialPoints = (0:0.5:10).';
solutions = zeros(size(initialPoints));
for k = 1:numel(initialPoints)
x0 = initialPoints(k);
solutions(k) = fminsearch(f, x0);
end
For ease of display I'll put the points in a table.
results = table(initialPoints, solutions)
2 Commenti
Steven Lord
il 22 Ott 2022
Okay. I'll use randi to compute my initial points, but you could use another function. In fact you could (except when whichTrial is 1) look at results(whichTrial-1) to use the results from the previous run as x0 for this run.
ntrials = 10;
initialPoints = zeros(ntrials, 1);
results = zeros(ntrials, 1);
f = @sin;
for whichTrial = 1:ntrials
x0 = randi([-10 10]); % You could compute this however you want
initialPoints(whichTrial) = x0; % Record it
results(whichTrial) = fminsearch(f, x0); % Compute with it
end
Now show the results table.
t = table(initialPoints, results)
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