calcforce

Note

Some versions of this command have been ported to the new APBS syntax (see YAML- and JSON-format input files):

• Nonpolar calculations: see nonpolar.Nonpolar.calculate_forces() for more information.
• Polar calculations:
  • Boundary element: see boundary_element.BoundaryElement.calculate_forces()
  • Finite difference: see finite_difference.FiniteDifference.calculate_forces()
  • Finite element: see finite_element.FiniteElement.calculate_forces()

This optional keyword controls energy output from an apolar solvation calculation. The syntax is:

calcforce {flag}

where flag is a text string that specifies the types of force values to be returned:

no

(Deprecated) don’t calculate any forces.

total

Calculate and return total electrostatic and apolar forces for the entire molecule.

comps

Calculate and return total electrostatic and apolar forces for the entire molecule as well as force components for each atom.

The possible outputs from calcforce are:

tot {n}

total force for atom n

qf {n}

fixed charge force for atom n

db {n}

dielectric boundary force for atom n

ib {n}

ionic boundary force for atom n

The values will be printed in three columns which correspond to the x, y, and z components of the force vector.

Note

This option must be used consistently (with the same flag value) for all calculations that will appear in subsequent PRINT input file section statements.