equil1 — balancing (nonnegative) pair of matrices
[T [,siz]]=equil1(P,Q [,tol])
two non-negative symmetric matrices
nonsingular matrix
vector of three integers
threshold
equil1 computes t such that:
P1=T*P*T' and Q1=inv(T)'*Q*inv(T) are as follows:
P1 = diag(S1,S2,0,0) and Q1 = diag(S1,0,S3,0) with
S1,S2,S3 positive and diagonal matrices with respective
dimensions siz=[n1,n2,n3]
tol is a threshold for rank determination in SVD