function   [pos,num]=ent_num_pos(mat,lb,up)
% num=ent_num(mat,lb,up)
% 
% Input: mat - a matrix
%        lb - lower bound
%        up - upper bound
% Output: num -returns the number of entries in mat that are >= lb and <= up.
%         pos - returns the positions in mat that are >= lb and <= up.
%

a=mat>=lb & mat<=up;
num=sum(a(:));
pos=a;