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Subsections

5 Directives Controlling Wavefunction Convergence

5.1 MAXCYC

This directive consists of a single data line, read to variables TEXT,MAXC using format (A,I).

The directive may be omitted when MAXC will be set to the default value of 50. The following conditions cause termination of iteration:

Example

          MAXCYC 100

Note that the maximum number of allowed cycles in CASSCF calculations is limited to 20.

5.2 THRESHOLD

This directive may be used to define a convergence threshold for SCF and MCSCF iterations, and comprises a single data line read to the variables TEXT, ISET using format (A,I);

At SCF convergence, the elements of the density matrix will be converged to within an absolute error 10-ISET. The directive may be omitted, when the default value 10-5 will be used. For CASSCF iterations values of the maximum Brillouin element (super-CI) or maximum first derivative (Newton Raphson) control the monitoring of convergence. Note that in most CASSCF and MCSCF calculations setting ISET=4 will prove quite adequate.


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Next: 6 SCF Convergence - Up: GAMESS-UK part4 Previous: 4 Directives defining the   Contents