function S=usHMat(v,n)
%function H=usHMat(v,n)
% form symmetric matrix with zero diagonal from vector
%Input:  v  in R^(t(n)-n)  
% Output:  S  symmetric with zero diagonal
%svind: linear indices of the **strictly** upper triangle by columns
svindu = logical(triu(ones(n),1));
S=zeros(n);
S(svindu)=v/sqrt(2);
S=S+S';
