Generate a matrix containing all combinations of elements taken from n vectors

by

The ndgrid function almost gives the answer, but has one caveat: n output variables must be explicitly defined to call it. Since n is arbitrary, the best way is to use a comma-separated list (generated from a cell array with ncells) to serve as output. The resulting n matrices are then concatenated into the desired n-column matrix:

vectors = { [1 2], [3 6 9], [10 20] }; %// input data: cell array of vectors

n = numel(vectors); %// number of vectors
combs = cell(1,n); %// pre-define to generate comma-separated list
[combs{end:-1:1}] = ndgrid(vectors{end:-1:1}); %// the reverse order in these two
%// comma-separated lists is needed to produce the rows of the result matrix in
%// lexicographical order 
combs = cat(n+1, combs{:}); %// concat the n n-dim arrays along dimension n+1
combs = reshape(combs,[],n); %// reshape to obtain desired matrix

More Related Contents:

  1. Linear indexing, logical indexing, and all that
  2. Using transpose versus ctranspose in MATLAB
  3. Creating Indicator Matrix
  4. Array of Matrices in MATLAB
  5. how to replicate an array
  6. How do I iterate through each element in an n-dimensional matrix in MATLAB?
  7. How do I remove elements at a set of indices in a vector in MATLAB?
  8. Vector norm of an array of vectors in MATLAB
  9. Excel-VBA – Insert new first column in datafield array without loops or API calls
  10. Repeat copies of array elements: Run-length decoding in MATLAB
  11. Element-wise array replication in Matlab
  12. arrayfun can be significantly slower than an explicit loop in matlab. Why?
  13. How do I do multiple assignment in MATLAB?
  14. MATLAB adding array elements iteratively: time behavior
  15. In MATLAB, when is it optimal to use bsxfun?
  16. How do i define a structure in Matlab
  17. Element-wise array replication according to a count [duplicate]
  18. Convert a matrix to a 1 dimensional array
  19. How to get all combinations from multiple arrays?
  20. What is the advantage of linspace over the colon “:” operator?
  21. In an assignment A(:) = B, the number of elements in A and B must be the same
  22. How to use cell arrays in Matlab?
  23. How to get mean, median, and other statistics over entire matrix, array or dataframe?
  24. Combining matrices into an array in R
  25. Is there anything like deal() for normal MATLAB arrays? [duplicate]
  26. Vector multiplication using MATMUL in Fortran
  27. convert string to number array in matlab
  28. Is indexing vectors in MATLAB inefficient?
  29. Is A==0 really better than ~A?
  30. How to filter an array of objects based on values in an inner array with jq?

Leave a Comment