4d Interpolation of Table

Question

River Vorse 2020-11-9

2
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/642170-4d-interpolation-of-table

回答： Raunak Gupta 2020-11-13

I'm trying to interpolate a set of 4

variable data values in a table. Can I use interpn() for this?

the first column ranges (0:2:10)- full table not shown since there are hundreds of values. The first three columns are inputs such that at x =0, y= 16, z=40, there are a number of outputs shown in the right 7 columns. I'm trying to interpolate so that if I have a set of inputs x = 0.5, y = 16.7, z = 37.2, I can interpolate a value for one of the outputs in the right 7 columns.

2 个评论
显示无隐藏无

River Vorse 2020-11-9

在 MATLAB Online 中打开

My thought is :

x = data(:,1);
y = data(:,2);
z = data(:,3);
v = data(;,4);
xp = 0.5;
yp = 16.7;
zp = 37.2;
vp = interpn(x,y,z,v,xp,yp,zp)

River Vorse 2020-11-9

this gives the following error

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Raunak Gupta 2020-11-13

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/642170-4d-interpolation-of-table#answer_544093

Hi,

The error when using interpn is due to the data not being present in Grid format, meaning for every triplet of (x,y,z) in some range of x,y,z should have a value v also present. You can create the Grid format data for x,y,z using

[X1, X2, X3] = ndgrid(x,y,z);

But for the same you need to reshape the 4th column such that it represents corresponding values in X1, X2, X3. For this the length of unique x,y,z is required which gives the indices where values for learning interpolation are present.

You can see here about how the input array should look like.