interpolation using 2D look up table

Hello

My Question is

I have matrices A,B gives C. All the matrices are stored in a workspace and has size 81x200.

I would like to interpolate them and store them in a 2D lookup table.

I had used the interp2 function but I am getting errors

could some one clarify this issue?

Answer 1

[Star Strider]

See if transposing all of them (use the simple transpose (.')) will work.

To see the difference between meshgrid and ndgrid results —

x = 1:3;
y = 4:6;

[X1,Y1] = meshgrid(x,y)

X1 = 3×3

1 2 3 1 2 3 1 2 3

Y1 = 3×3

4 4 4 5 5 5 6 6 6

[X2,Y2] = ndgrid(x,y)

X2 = 3×3

1 1 1 2 2 2 3 3 3

Y2 = 3×3

4 5 6 4 5 6 4 5 6

Transposing all of them should put them in ndgrid format.

.

[SGK]

For eg

A=[1 2 3]

B=[2 3 4]'

C= 20

But If I know the value of C= 35

is it possible to find the A and B matrices from C buy ndgrid/meshgrid Function?

[Star Strider]

You need to have some sort of relation that uses matrices ‘A’ and ‘B’ to produce values of matrix ‘C’ for each element of ‘A’ and ‘B’. After that, given any value within the limits of ‘A’ and ‘B’, you can interpolate to get a new value for ‘C’. You can potentially use any two matrices to interpolate the value of the third matrix, however that likely comes with restrictions, since in that instance there cannot be any repeating values of, and it would be best if was monnotonically increasing or decreasing. It might not be possible to find the ‘A’ and ‘B’ matrices given any specific value of ‘C’ except in some restricted instances. That would certainly not be true generally.