matlab: vectorizing a single loop that is ORing N binary matrices -

the below code computation on data matrix, data laid --

data = [ ...         1 2 3 4 5 6; ...         1 2 3 4 5 6; ...         1 2 3 4 5 6;]  

and code running --

[~,col] = size(data) ; flag1 = bsxfun(@lt, data(:,1), data(:,1).');  flag2 = bsxfun(@gt, data(:,1), data(:,1).');   cindex = 2:col % can rid of loop ?     flag1 = flag1 | bsxfun(@lt, data(:,cindex), data(:,cindex).');     flag2 = flag2 | bsxfun(@gt, data(:,cindex), data(:,cindex).'); end 

what code doing comparing each row in column major order , creating 2 matrices of binary values flag1 , flag2.

is there anyway rid of for cindex = 2:col loop ?

you need permuting(rearrange dimensions) create singleton dimensions expansions take place when using bsxfun later on, replace looping used in original posted code. so, implementation -

flag1 = any(bsxfun(@lt,permute(data,[1 3 2]),permute(data,[3 1 2])),3); flag2 = any(bsxfun(@gt,permute(data,[1 3 2]),permute(data,[3 1 2])),3);