19.5 Convergence thresholds

As for the print options, there are global and local thresholds, specified using the gthresh and thresh directives, respectively. Here we only mention some useful global thresholds (default values are shown).

gthresh,energy=1.d-6     !convergence threshold for energy.
                         !This affects all iterative methods
gthresh,orbital=1.d-5    !convergence threshold for orbitals.
                         !This affects scf only
gthresh,step=1.d-3       !convergence threshold for orbital rotations
                         !This affects mcscf only
gthresh,gradient=1.d-2   !convergence threshold for gradient with respect to
                         !orbital rotations. This affects mcscf only
gthresh,civec=1.d-5      !convergence threshold for ci-coefficients in ci and ccsd.
gthresh,optgrad=3.d-4    !threshold for gradient in geometry optimizations
gthresh,optenerg=1.d-6   !threshold for energy in geometry optimizations
gthresh,twoint=1.d-11    !Threshold for neglect of small 2-electron integrals
gthresh,compress=1.d-11  !Accuracy of integral compression (depends on twoint)
gthresh,printci=0.05     !print all ci-coefficients larger than 0.05
gthresh,punchci=0.05     !write all ci-coefficients larger than 0.05 to the punch file

Note that the energy threshold also affects the defaults for some other thresholds such as orbital, step, and civec, and therefore it is normally sufficient to lower the energy threshold if high accuracy is needed.

Any number of thresholds can be specified on a single gthresh directive, e.g.,


molpro@molpro.net 2018-12-16