Matlab：如何将变量的渐进值与其以前的最佳值进行比较并将其重新分配给以前的最佳值？

Question

我有一段代码可以在循环中评估变量的性能，这样我们就可以检查它的进度并将其与它的最佳值进行比较，如果新分配的值是，则将其分配回这个最佳值评估为不优于此变量在其最佳值时的性能。

for (True) 

err = sum(Y*X'*w <=0);   %measure the performance of w for fixed X and Y variables.
err_best = sum(Y*X'*wbest <=0);  %measure the performance of w best
if(err <= err_best)              %if performance of newly assigned value of w is better than that of its career best wbest then update wbest with this newly identified best value.
    wbest = w;            %update the value of wbest if the w is evaluated to be better than the previous best wbest.
end
w = wbest;                 % wbest is updated to the best value evaluated thus far and assign to w this value.

% Code to change w value.

end

请忽略其余代码，因为这对这个问题无关紧要。我想知道如何保留变量 w 的最佳值并将其存储在 wbest 中，因为 w 变量会一遍又一遍地更改它。到目前为止，这段代码没有给出预期的结果，其余代码不需要任何更改。

Answer 1

您始终可以在 wbest 中附加最佳值，并将 wbest(end) 用作“迄今为止最佳”，例如：

for (True) 

err = sum(Y*X'*w <=0);   %measure the performance of w for fixed X and Y variables.
err_best = sum(Y*X'*wbest(end) <=0);  %measure the performance of w best
if(err <= err_best)              %if performance of newly assigned value of w is better than that of its career best wbest then update wbest with this newly identified best value.
    wbest = [wbest w];            %update the value of wbest if the w is evaluated to be better than the previous best wbest.
end
w = wbest(end);                 % wbest is updated to the best value evaluated thus far and assign to w this value.

% Code to change w value.

end

这将确保您在退出循环时拥有wbest 的历史记录。