how to minimize set of values with genetic algorithm

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Folashade Adewara 2019-4-29

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评论： Folashade Adewara 2019-4-30

function  [z] = see(x1,x2,x3,x4,x5,d)
%optimization of okumura-hata model  
x1=69.55;
x2=26.16;
x3=44.9;
x4=6.55;
x5=13.82;
d= 0.1:0.1:1;
z = x1 + x2*2.903+(x3-x4*1.477)*log10(d)-x5*1.477-(-9.1905e-04);

Good day, I'm trying to minimize the values for x1, x2,x3,x4, and x5 with genetic algorithm so that i can get reduced sets of values for Z.

how do i go about this? because it keeps giving me the same values.

Thanks.

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采纳的回答

Stephan 2019-4-29

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https://ww2.mathworks.cn/matlabcentral/answers/459084-how-to-minimize-set-of-values-with-genetic-algorithm#answer_372735

编辑：Stephan 2019-4-29

Hi,

you do not call ga here. Also your function would overwrite every input of x by the fixed values for x1...x5 inside your function - try this instead:

%% Optimization of okumura-hata model 
% Values & Preallocation
d= 0.1:0.1:1;
x = zeros(1,5);
res = nan(numel(d),numel(x));
% Objective function
see = @(x,d) x(:,1) + x(:,2).*2.903+(x(:,3)-x(:,4).*1.477).*log10(d)...
    -x(:,5).*1.477-(-9.1905e-04);
% Optimization options
opts = optimoptions(@ga, 'MaxGenerations', 10000, 'Vectorized', 'on',...
    'Display', 'off');
% Calculate optimal x-values for each d-value in a loop
for k = 1:numel(d)
    res(k,:) = ga(@(x)see(x,d(k)),numel(x),opts);
end
% Calculate minimized z-values
function_values = diag(see(res,d));
% Show results
res
function_values

in the variable res every line represents one value of d. The columns represent the x-values:

res =
   1.0e+04 *
   -2.5616   -5.0637    2.5757   -3.3401    3.1734
   -2.6833   -5.2522    2.0992   -2.8011    3.4996
   -2.8103   -5.3935    1.7644   -2.4866    3.5266
   -2.9549   -5.4026    1.5468   -2.0186    3.6395
   -2.8763   -5.5699    1.4268   -1.7981    3.6919
   -2.9868   -5.5456    1.1051   -1.3898    3.7409
   -2.8976   -5.5831    0.7727   -1.0403    3.7109
   -3.0164   -5.4932    0.5235   -0.8457    3.7306
   -2.9913   -5.6476    0.2559   -0.4003    3.7077
   -3.0280   -5.6128    0.0108   -0.0606    3.6301

The resulting function values are:

 function_values =
   1.0e+05 *
   -2.9458
   -2.7458
   -2.6519
   -2.5816
   -2.5728
   -2.5311
   -2.4944
   -2.4645
   -2.4901
   -2.4683

Best regards

Stephan

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Stephan 2019-4-30

编辑：Stephan 2019-4-30

try:

% Objective function
see = @(x,d) x(1) + x(2)*2.903+(x(3)-x(4)*1.477).*log10(d)...
  -x(5)*1.477-(-9.1905e-04);
% Optimization options
opts = optimoptions(@ga, 'Display', 'off');