function A = SymBand2Quad (ABand)
[n,ib] = size (ABand) ;
A = zeros (n,n) ;
for i=1:n
    if (i+ib <= n) jog=ib ; else jog=n-i+1 ; end
    for j=1:jog
        A(i,i+j-1) = ABand(i,j) ;
        A(i+j-1,i) = ABand(i,j) ;
    end
end