These option control the solution of eigenvalue-problems and linear systems of equations.

**Number of QL-iterations in eigensystem computation: 60**.

This value is needed to calculate the eigensystem of the Hessian matrix of RHO. Since the Hessian is a 3 by 3 symmetric matrix, the default number of iterations is nearly always sufficient.**Matrix is considered singular if pivot element is less than: 1e-012**.

Some linear systems must be solved with the Hessian matrix of RHO. Gaussian algorithm with partial pivoting is used. AIM2000 will assume that the Hessian is singular if the absolute value of a pivot element falls below this value.