matlab - Straighten and concatenate the individual grids from ndgrid -

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• generate matrix containing combinations of elements taken n vectors 4 answers

i'm trying following in general way:

x = {0:1, 2:3, 4:6}; [a,b,c] = ndgrid(x{:}); res = [a(:), b(:), c(:)] res =    0   2   4    1   2   4    0   3   4    1   3   4    0   2   5    1   2   5    0   3   5    1   3   5    0   2   6    1   2   6    0   3   6    1   3   6 

i believe have start following way, can't figure out how continue:

cell_grid = cell(1,numel(x)); [cell_grid{:}] = ndgrid(x{:}); [cell_grid{:}] ans =     ans(:,:,1) =    0   0   2   3   4   4    1   1   2   3   4   4 ans(:,:,2) =    0   0   2   3   5   5    1   1   2   3   5   5 ans(:,:,3) =    0   0   2   3   6   6    1   1   2   3   6   6 

i can solve in many ways case 3 variables [a, b, c], both , without loops, start struggle when more vectors. reshaping directly not give correct result, , mixing reshape permute becomes hard when have arbitrary number of dimensions.

can think of clever way scales 3-30 vectors in x?

you can use cellfun flatten each of cell array elements , concatenate them along second dimension.

tmp = cellfun(@(x)x(:), cell_grid, 'uniformoutput', false); out = cat(2, tmp{:}) 

alternately, avoid cellfun , concatenate them along dimension 1 higher dimension of each cell_grid member (i.e. numel(x) + 1). reshape flatten dimensions last 1 concatenated along.

out = reshape(cat(numel(x) + 1, cell_grid{:}), [], numel(x));