Hi, I have a 4D data file from MATLAB, call it X,  that I want to analyze in
R. The first 3 dimensions are x y z coordinates and the forth is a value in
time.

If you took a sample vector in matlab it would look like

vec1 = X(x1, y1, z1, :)
vec2 = X( x2, y2, z2, :)

this would give you all values (I have 300 of them) corresponding to this
(x1,y1,z1) point of X.

Now I read the MATLAB datafile 4D X into R and want to address vec1 and vec2
in R and work with the fourth column values only.

I tried something like X[ x1, y1, z1, ] to pull out the 4th column values
but R tells me that X has incorrect dimensions.

I'd like to start with being able to find say correlation between vec1 and
vec2

Any suggestions?

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