wolffd@0: function p = find_equiv_posns(vsmall, vlarge)
wolffd@0: % FIND_EQUIV_POSNS p[i] = the place where vsmall[i] occurs in vlarge.
wolffd@0: % p = find_equiv_posns(vsmall, vlarge)
wolffd@0: % THE VECTORS ARE ASSUMED TO BE SORTED.
wolffd@0: %
wolffd@0: % e.g., vsmall=[2,8], vlarge=[2,7,8,4], p=[1,3]
wolffd@0: %
wolffd@0: % In R/S, this function is called 'match'
wolffd@0:  
wolffd@0: %if ~mysubset(vsmall, vlarge)
wolffd@0: %  error('small domain must occur in large domain');
wolffd@0: %end
wolffd@0: 
wolffd@0: if isempty(vsmall) | isempty(vlarge)
wolffd@0:   p = [];
wolffd@0:   return;
wolffd@0: end
wolffd@0:   
wolffd@0: bitvec = sparse(1, max(vlarge)); 
wolffd@0: %bitvec = zeros(1, max(vlarge));
wolffd@0: bitvec(vsmall) = 1;
wolffd@0: p = find(bitvec(vlarge));
wolffd@0: 
wolffd@0: %p = find(ismember(vlarge, vsmall)); % slower