How to reshape a vector without knowing the dimensions?
14 views (last 30 days)
Show older comments
Hello,
I had a 3d matrix 663x3127x254. I removed NaN's using a mask and now I assume I have less elements on the left most dimension as in vector form:
s = 526593054 x 1, i = 67510073 x 1 (this is my mask, a magnitude lower)
How can I reshape the mask vector into a 3d matrix without knowing the new dimensions?
I am familiar with the function 'reshape' but only when I know the previous dimensions.
here is my code:
i = find(~isnan(s));
s = s(i);
My ultimate goal is to use it for triscatteredinterp.
thanks, Michael
0 Comments
Accepted Answer
Christopher Berry
on 5 Aug 2014
Using reshape with only 2 dimensions specified will work only if the number of elements is such that the 3rd dimension fits exactly. You can do better by picking the 3 dimensions yourself using factor
factor(numel(s))
Multiply these factors any way you want to produce 3 non prime values. Then use these 3 non prime factor values with reshape. For example, if numel(s) = 64 :
factor(64)
ans =
2 2 2 2 2 2
Then any of the following triples will work with reshape
(2,8,4) (4,4,4) (1,16,4)
0 Comments
More Answers (3)
Azzi Abdelmalek
on 5 Aug 2014
You needat least, know the first two dimensions, the use
reshape(i,663x3127,[])
but this is not always possible, depending of the size of i
0 Comments
Sean de Wolski
on 5 Aug 2014
Edited: Sean de Wolski
on 5 Aug 2014
If you're using this for TriScatteredInterp, why do you need it as a three d array?
Couldn't you build it from a meshgrid (with corresponding nan points removed)?
% v is your matrix
[xx,yy,zz] = meshgrid(1:size(v,1),1:size(v,2),1:size(v,3));
idx = ~isnan(v);
xxv = xx(idx);
yyv = yy(idx);
zzv = zz(idx);
vv = v(idx);
T = TriScatteredInterp([xxv yyv zzv],vv)
I would also recommend using scatteredInterpolant over TriScattereredInterp if you're on a newer release.
0 Comments
See Also
Categories
Find more on Wireless Communications in Help Center and File Exchange
Products
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!