Undefined operator .^ occurs help!!

2019 4 29
2 个回答
回答已采纳
更新时间：2019 4 29
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I’m doing homework; actually basic class. I just wrote everything on the given material, but I can’t still get the answer. Here’s codes:
xdata = { 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1 1.05 1.1 1.15 1.2 1.25 1.3 1.35 1.4 1.45 1.5 1.55 1.6 1.65 1.7 1.75 1.8 1.85 1.9 1.95 2 };
ydata = { 5.17641 4.20461 3.31091 2.60899 2.23541 1.97771 1.88141 1.62821 1.50138 1.51075 1.4085 1.26222 1.09432 1.13202 1.12918 1.10355 1.11867 1.0974 1.08324 1.05687 1.19422 1.22984 1.34516 1.19713 1.25398 1.29885 1.33658 1.31166 1.40332 1.3955 1.37855 1.41491 1.59549 1.56027 1.63925 1.7244 1.74192 1.82049 };
fun = @(p) sum((ydata-(1/3)*(xdata.^2 + (2*(1+p)/xdata)))^2);
pguess = 0.1;
[p,fminres] = fminsearch(fun,pguess)
What is the problem with these codes? Would you help me?

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 采纳的回答

Stephen23
Stephen23 2019-4-29
编辑：Stephen23 2019-4-29

1 个投票

"I just wrote everything on the given material"
If that is the case then that material is wrong:
  • {} creates a cell array (similar to a list in other languages),
  • [] concatentates those numeric scalars into one numeric array:
xdata = [0.15 0.2 ...1.9 1.95 2];
^ ^ Creates a numeric array from numeric scalars!
It seems that your function is also missing a few characters:
fun = @(p) sum((ydata-(1/3)*(xdata.^2 + (2*(1+p)./xdata))).^2);
^ ^
After which i get:
p = 0.19589
fminres = 0.26543

更多回答（1 个）

KSSV
KSSV 2019-4-29
编辑：KSSV 2019-4-29

1 个投票

xdata = [0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1 1.05 1.1 1.15 1.2 1.25 1.3 1.35 1.4 1.45 1.5 1.55 1.6 1.65 1.7 1.75 1.8 1.85 1.9 1.95 2 ];
ydata = [ 5.17641 4.20461 3.31091 2.60899 2.23541 1.97771 1.88141 1.62821 1.50138 1.51075 1.4085 1.26222 1.09432 1.13202 1.12918 1.10355 1.11867 1.0974 1.08324 1.05687 1.19422 1.22984 1.34516 1.19713 1.25398 1.29885 1.33658 1.31166 1.40332 1.3955 1.37855 1.41491 1.59549 1.56027 1.63925 1.7244 1.74192 1.82049 ];
fun = @(p) sum((ydata-(1/3).*(xdata.^2 + (2*(1+p)./xdata))).^2);
pguess = 0.1;
[p,fminres] = fminsearch(fun,pguess)
{} replace by []. {} is a cell. [] is a matrix.

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