Turning doubles of different dimensions in cells

temp = [time, Dynamics];
temp = num2cell([temp{:}]);

Hey guys,

I have a 1x6 cell called temp. It contains doubles with different dimensions:

double 222x1 double 222x1 double 222x1 double 222x1 double 222x1 double 151x1

Is there a way to 'trick' the num2cell function to the make the temp cell look like being made of consistent dimensions?

Thanks a lot for your help! :-)

Best,

Sven

Answer 1

[Image Analyst]

I can think of two ways

1. Create a matrix with a height of the tallest vector, and then paste the vectors in. Short vectors will have zeros below them in their column.
2. Interpolate the short vectors to be the same length as the taller ones using interp1() spline() or similar functions.

Would any of those methods suffice?

[Sven Krasel]

Hi Image Analyst,

Thanks for your reply! Would you mind helping me with the code for this?

Best,

Sven

[Image Analyst]

Which option do you want?

[Sven Krasel]

I am not very experienced in coding in MATLAB tbh. Maybe you can show me the way which seems to be the easiest for you?

Best,

Sven

[Image Analyst]

Sven, try this and see if either one of these two ways meets your needs. I did it both ways for you, but it really seems that you should know in advance which way meets your needs since they give totally different results.

% Create sample data.
temp = {rand(222,1), rand(222,1), rand(222,1), rand(222,1), rand(222,1), rand(151,1)}
% Get height
maxHeight = -inf;
for k = 1 : length(temp)
	maxHeight = max(maxHeight, size(temp{k}, 1))
end

%------------------------------------------------------------------------------------------
% Method 1 : past columns onto canvass matrix.
% Make matrix to hold values.
m = zeros(maxHeight, size(temp, 2));
% Stuff each cell of temp into a column of m.
for col = 1 : length(temp)
	thisCellContents = temp{col};
	m(1 : size(thisCellContents, 1), col) = thisCellContents;
end
m % Show in command window.

%------------------------------------------------------------------------------------------
% Method 2 : interpolate instead of pasting.
% Make matrix to hold values.
m2 = zeros(maxHeight, size(temp, 2));
% Stuff each cell of temp into a column of m.
for col = 1 : length(temp)
	thisCellContents = temp{col};
	thisMatrixHeight = size(thisCellContents, 1);
	interpolatedColumn = interp1((1:length(thisCellContents))', thisCellContents, linspace(1, thisMatrixHeight, maxHeight)');
	m2(:, col) = interpolatedColumn;
end
m2 % Show in command window.

[Sven Krasel]

Hey Image Analyst,

thanks a lot for your solutions. I am still testing and trying to understand both to find out which one suits my purposes better.

What is the maxHeight = -inf at the beginning of your code for?

Cheers,

Sven

[Image Analyst]

If you're going to get each max, and compare it to the current max, you need to have a current max for the very first time you do that. So for the very first time, before you've even looked at any of your variable values, what would be a good value to compare it against such that your first variable value will be guaranteed to be the max so far? Minus infinity of course. Any value you have is certainly guaranteed to be greater than minus infinity, right?

[Sven Krasel]

Hey Image Analyst,

that's a total reasonable explanation. Thanks for that. Also Method 1 works perfectly and does exactly what I want. Thank you very much!

Cheers,

Sven