Extract output data from meshgrid input
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I have some data which I have interpolated as follows:
Data = load("data.txt")
x = Data(:,1);
y = Data(:,2);
z = Data(:,3);z=-z;
c = Data(:,4);
F = scatteredInterpolant(x,y,z,c);
N = 50;
xvec = linspace(min(x), max(x), N);
yvec = linspace(min(y), max(y), N);
zvec = linspace(min(z), max(z), N);
[xq, yq, zq] = meshgrid(xvec, yvec, zvec);
vq = F(xq, yq, zq);
What I want to do is to extract the value of vq for a given xq,yq,zq.
Like vq(xq==21.7267 & yq==36.9072 & zq==-0.9551), which gives me an empty column vector.
If I do F(21.7267,36.9072,-0.9551) is this the correct vq?
采纳的回答
Cris LaPierre
2021-2-14
编辑：Cris LaPierre
2021-2-14
0 个投票
Always more helpful for us if you share 1) your data and 2) the complete error message (all the red text).
This example on the scatteredInterpolant documentation page shows how to use the results of meshgrid to determine vq. Make sure you are using the 4th input correctly. MATLAB expects it to be the sample values, specified as a vector that defines the function values at the sample points, v = F(x,y,z).
5 个评论
tandemuse
2021-2-14
Walter Roberson
2021-2-14
I don't think that is the issue. The issue is that the logical comparisons were each true for multiple locations, and indexing with multiple selected values in multiple indices gets you results at the cross-product rather than at the intersection.
Walter Roberson
2021-2-14
Yes, that would recalculate rather than extract from the stored value.
However is your z positive or negative? You changed sign compared to your other comments
tandemuse
2021-2-14
更多回答（1 个）
Walter Roberson
2021-2-14
vq(xq==2 & yq==3 & zq==5)
3 个评论
Walter Roberson
2021-2-14
better yet is ismembertol instead of ==
tandemuse
2021-2-14
Walter Roberson
2021-2-14
That why I said to use ismembertol()
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