Finding all existing minimums of a function
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I have this function:
I need to find all existing minimums of this function using fminsearch and also draw a 3D plot with minimum points highlighted on it.
What I've tried so far:
fun2 = @(x,y)x^4+y^4-2*x^2+4*x*y-2*y^2+1
x = fminsearch(@(v) fun2(v(1),v(2)),[-5,-5])
figure
[X, Y] = meshgrid(-2:0.1:2);
surf(X,Y,fun2(X,Y));
Result doesn't seem right:
采纳的回答
Image Analyst
2021-4-25
If you're going to pass in matrices for x and y, like X and Y from the output of meshgrid, you're going to have to use dots in the operators in your function:
fun2 = @(x,y) x .^ 4 + y .^ 4 - 2 * x .^ 2 + 4 * x .* y - 2 * y .^2 + 1;
3 个评论
Saba Asanidze
2021-4-25
Image Analyst
2021-4-25
I don't know. If it were me, I'd do it numerically. I'd evaluate the function everywhere, like between -2 and 2 or -5 and 5 or whatever you want, and then use imregionalmin() in the Image Processing Toolbox to find the local min locations.
Walter Roberson
2021-4-25
fminsearch only ever returns one location per call. If you call it with different initial values it may return a different location.
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