Download User's Guide S I E S T A 3.1

displacements using MD.Broyden.Initial.Inverse.Jacobian. For the FIRE method,
the same result can be obtained by choosing a small time step.
Note that there are Zmatrix-specific options that override this option.
Default value: 0.2 Bohr
MD.PreconditionVariableCell (real length): A length to multiply to the strain components
in a variable-cell optimization. The strain components enter the minimization on the same
footing as the coordinates. For good efficiency, this length should make the scale of energy
variation with strain similar to the one due to atomic displacements. It is also used for
the application of the MD.MaxCGDispl value to the strain components.
Use: Used only if MD.TypeOfRun is CG or Broyden or FIRE and MD.VariableCell is .true.
Default value: 5.0 Ang
ZM.ForceTolLength (real force): Parameter that controls the convergence with respect to
forces on Z-matrix lengths
Use: This option sets the convergence criteria for the forces that act on Z-matrix components with units of length.
Default value: 0.00155574 Ry/Bohr
ZM.ForceTolAngle (torque): Parameter that controls the convergence with respect to forces
on Z-matrix angles
Use: This option sets the convergence criteria for the forces that act on Z-matrix components with units of angle.
Default value: 0.00356549 Ry/rad
ZM.MaxDisplLength (real length): Parameter that controls the maximum change in a Zmatrix length during an optimisation step.
Use: This option sets the maximum displacement for a Z-matrix length
Default value: 0.2 Bohr
ZM.MaxDisplAngle (real angle): Parameter that controls the maximum change in a Z-matrix
angle during an optimisation step.
Use: This option sets the maximum displacement for a Z-matrix angle
Default value: 0.003 rad
7.1.1
Conjugate-gradients optimization
This was historically the default geometry-optimization method, and all the above options were
introduced specifically for it, hence their names. The following pertains only to this method:
MD.UseSaveCG (logical):
Instructs to read the conjugate-gradient hystory information
stored in file SystemLabel.CG by a previous run.
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