How to convert a matrix into a 3d matrix
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More Answers (3)
Image Analyst on 11 Dec 2013
Edited: Image Analyst on 11 Dec 2013
If you're in a loop, you can do
for k = 1 : numberOfLoopIterations
thisMatrix = yourFunction();
if k == 1
% Start it/initialize it.
matrix3D = thisMatrix;
% Append this matrix in 3D to the "master" one.
matrix3D = cat(3, matrix3D, thisMatrix);
Walter Roberson on 12 Dec 2013
As you asked the question again, I will repeat what Image Analyst said, but with different wording:
In order to combine vectors unchanged into a numeric matrix, the vectors must all be the same length. There is no way to overcome this limitation in a numeric matrix.
You can chop all the vectors down to the same length, by throwing away information. After that you can use cat() to combine them into a numeric matrix.
You can extend the short vectors with some value (such as 0 or inf or NaN) so that the vectors are all the same length. After that you can use cat() to combine them into a numeric matrix.
Now another option: if you have several vectors of coordinates (such as time) and corresponding values, then you can determine some "representative" coordinates and use interp1() to interpolate the values at the representative coordinates, for each vector. After that you can use cat() to combine the interpolated values into a numeric matrix. For example:
L1 = length(v1); L2 = length(v2); L3 = length(v3);
new_L = mean([L1, L2, L3]); %number of points we will interpolate at
all_v = vertcat(v1(:), v2(:), v3(:)); %combine all of the vectors
minv = min(all_v);
maxv = max(all_v);
new_v = linspace(minv, maxv, new_L); %equally spaced values between the min and max
new_y1 = interp1(v1, y1, new_v);
new_y2 = interp1(v2, y2, new_v);
new_y3 = interp1(v3, y3, new_v);
combined_y = vertcat(new_y1(:), new_y2(:), new_y3(:));