Storing values using csapi (spline functin)

I have been trying to use csapi. This command will work: x = [0 1 2 3]; y = [0 1 2 3]; csapi(x,y); However, I am trying to let x be a cell array. x = {[0 1 2 3] [0 1 2 3]}; y = [0 1 2 3]; Basically I want my "x" to be a table with different values. csapi(x,y); will not work for this case. Is this possible? I appreciate any help.

Answer 1

[Sean de Wolski]

Why not just use a for-loop?

Or you coudl write a wrapper function around csapi that uses a for-loop internally but allows you to call it with a cell array.

Just my $0.02

[Mauricio Marulanda]

Well the for loop will not really fix it. I cannot even get one entry store. For instance,

x = [0] [1x2 double] and y = [0 1]; csapi(x,y)

gives me an error: [b,v,l,k] = ppbrk(csapi1(x{i}, reshape(v,prod(sizev(1:m)),sizev(m+1)) ));

[Sean de Wolski]

post the full code of what you tried, it should be something like this:

C = your cell a cell arrasy

for ii = 1:length(C)

result{ii} = csapi(C{ii},y)

end

[Mauricio Marulanda]

My code looks like this:

index = 1

for i = 1:length(a)

for j = 1:length(b)

for k = 1:length(c)

for l = 1:length(d)

y(i,j,k,l) = value_array(index);

index = index+1;

end

end

end

end

st{1} = csapi({a,b,c,d},y);

where a = [1:5], b = [1:3], c = [4:6], d=[50:100]; and value_array = [1 2 3 4 .... length(a)*length(b)*length(c)*length(d)]

Hope this clears my problem. Thanks

[Sean de Wolski]

Still not going to work because csapi doesn;t want cell arrays!

I would recommend writing

out = csapiCell(Cx,y)

for ii = length(Cx):-1:1

out{ii} = csapi(Cx{ii},y);

end

[Sean de Wolski]

save those four lines of code as csapiCell somewhere on the MATLAB path.

[Mauricio Marulanda]

So csapi doesnt take cell arrays. I understand.

What does this line do?

out = csapiCell(Cx,y)

[Mauricio Marulanda]

And to clarify, in csapi(x,y); x has to be one dimensional array.

I would have to come up with something likeL

x = f(a,b,c,d) %refering to my previous code

y = [y1 y2 ... length(x)] %length(x) = length(a)*len(b)*len(c)*len(d)

out = csapi(x,y)

[Sean de Wolski]

csapiCell the four lines of code I wrote above, if saved as an *.m file will be a wrapper that calls csapi with the contents of each cell. and returns a cell.

[Mauricio Marulanda]

Ok Sean, thanks a lot, but tell me, definitively the csapi will not accept a cell array with values, it has to be a single array?

[Sean de Wolski]

If called correctly it will take a cell array:

doc csapi

[Mauricio Marulanda]

according to the document as long as "if x is sequences x1, ..., xm, of lengths n1, ..., nm respectively, then y is expected to be an array, of size [n1,...,nm]"

then why st{1} = csapi({a,b,c,d},y); will not work if

x is a cell array and

y is pretty much (y1..length(a), y2..length(b), y3..length(c), y4..length(d))

Answer 2

[Mauricio Marulanda]

I believe based on the comments the best way to do this: Come up with something like this. x = f(a,b,c,d) %refering to my previous code Where x is a unique function of a,b,c,d. y = [y1 y2 ... length(x)] %length(x) = length(a)*len(b)*len(c)*len(d) out = csapi(x,y)