Using Cell Arrays in Interpolants

I have a griddedInterpolant F and some of the input variables are in a cell array form. As an example, this is how I created the interpolant F:

[x,y,z] = ndgrid(-5:1:5);
t = x+y+z;
mycell  = {x,y};
F = griddedInterpolant(mycell{:},z,t);

In reality, the size of the cell array mycell changes each time I run the code, and that's why I figured I have to use a cell array as an input. Up to this point everything works beautifully and I get my interpolant F without any problems.

Now I'd like to call the interpolant F in another function. When I have a single row for each input, everything works fine as shown in the following example:

testcell = {1,3};
F(testcell{:},5)

ans =

       9

However, when I'd like to have each input in a vector form, the interpolant doesn't work and I get the following error:

testcell = {1,3; 2, 4};
F(testcell{:,:},[5;1])
Error using griddedInterpolant/subsref
Invalid arguments specified in evaluating the interpolant.

Because I don't know the dimensions (particularly number of columns) of my actual cell array, I can not break testcell apart manually. This means that my input data might be 3D, but I can't call the interpolant F as F(input1, input2, input3) because I don't know whether it is 3D. As a side note, the code does know the dimensions of the data. I'd like to use vector inputs for each input variable of F in order to call F for n number of cases at once without a for loop. (i.e. each input has a size of nx1, hence the output should also be a vector of nx1)

What is the right way to call the interpolant F in this case?

Answer 1

[Nicolas Schmit]

There is a problem with your last snippet of code. Here is how you should correct it.

testcell = {[1;3]; [2; 4]};
F(testcell{:},[5;1])

[swenia]

You, sir, just ended my misery. Thank you!

[swenia]

Just a follow up question to this answer, if I have a matrix of

testmat = [1,2 ; 3,4]

how can I transform this into:

testcell = {[1;3]; [2; 4]};

I've been using testcell = num2cell(testmat) command but it doesn't do the trick, apparently. I can do it using a for loop, but just wondering if there is a single line command for that.

[Nicolas Schmit]

Use

testcell  = num2cell(testmat,1)'

https://www.mathworks.com/help/matlab/ref/num2cell.html

[swenia]

Thank you!