An Example

As an example, consider the following spec file. 

BEGIN

PRINT-LEVEL 2

ITERATIONS-BETWEEN-PRINTING 5

MAXIMUM-NUMBER-OF-ITERATIONS 50

CHECK-DERIVATIVES

EXACT-SECOND-DERIVATIVES-USED

BANDSOLVER-PRECONDITIONED-CG-SOLVER-USED 10

END

Then we wish to:

• Minimize the objective function. 
• Print an expanded summary every fifth iteration.
• Stop after 50 iterations.
• Save the solution data only at the end of the optimization.
• Check the derivatives of the group and nonlinear element functions, stopping if the check reveals possible errors.   
• Use exact first and second derivatives.  
• Forgo automatic problem scaling. 
• Use default stopping tolerances. 
• Use a ``box'' shaped trust region, whose initial radius is chosen internally by LANCELOT. 
• Accept an inaccurate solution of the inner iteration subproblem.
• Find the exact Cauchy point at each iteration. 
• Use a preconditioned conjugate gradient   linear equation solver. The preconditioner is based on ignoring all elements which lie outside a band of width 11 (semibandwidth 10) from the diagonal  of the coefficient matrix. The remaining band matrix is factorized and its diagonals modified to ensure that the modified band matrix is positive definite.   
• Start from the initial point specified in the SIF file.