4.7 System variables
| Variable | Type | Unit | Read only | Description |
| acell | F | Å | N |
Cell parameter for non-bonded potential (USE periodic). |
| b64enc | I | N |
Use the Base64 encoding algorithm for the binary dump (see BINDUMP command). This function is useful to transfer raw data trough 7-bit terminals (e.g. by telnet protocol). |
|
| bbox | F | Å | N |
Box dimension used by box potential (USE box). |
| bcell | F | Å | N |
Cell parameter for non-bonded potential (USE periodic). |
| ccell | F | Å | N |
Cell parameter for non-bonded potential (USE periodic). |
| charge | F | Y |
Total charge. |
|
| cutoff | F | Å | N |
Cutoff radius for long-range non-bond energy calculation. AMMP is faster without cutoffs than with them. Cutoffs are also physically incorrect and should not be used except as a bad example. The typical values are 8.0 to 10.0 Å. The default value is 0.0 Å(= no cut-off). |
| dddr | F | - | N | Scale factor used in the react electrostatic potential (USE react). |
| dend | I | - | N |
Binary I/O endian (0 = little endian, 1 = big endian). See BINDUMP command. |
| dielect | F | F/m | N |
Dielectric constant. It must be equal or greater than 1.0. |
| hend | I | Y |
Hardware endian (0 = little endian, 1 = big endian). |
|
| kfourd | F | - | N |
Force constant used in 4D non-bonded energy evaluation (USE shadow). |
| l2f | F | - | Y | Return the l2 normal of the forces. |
| lamda | F | - | N |
Potential homotopy parameter (see USE command). The valid values are 0.0 ≤ lambda ≤ 1.0 (default 0). |
| lmaxf | F | - | Y | Return the maximum l2 metric of a force an a an atom. |
| mmbox | F | Å | N |
Enable the fast multipole algorithm (FMM) for long-range non-bond energy calculation setting it to a value greater than zero. 10 Å is the optimal compromise between accuracy and speed. The FMM is not worth using unless the system is larger than 1000 atoms or greater in size than 30 Å. |
| mxcut | F | - | N |
Cutoff value for short range electrostatic calculation. It must be greater then zero (default 6.0 Å). |
| mxdq | F | Å | N |
Update full non-bonded list when atomic displacement is greater than value in angstroms. Typical values are 0.5 to 0.75 Å. |
| mxperiter | I | - | N |
Maximum number of perturbation iteration performed by the Boltzmann jump conformational search. See TJUMP command. |
| nostep | I | - | N | Number of steps used in the line minimizer. |
| numatm | I | - | N | Number of atoms. |
| nupdat | I | - | N | Update frequency for the graphic interface. |
| occup | F | - | N | Occupancy value. See RICHARD command. |
| pi | F | - | Y |
Pi-greco constant. |
| rdebye | F | - | N |
Debye constant for Debye screened non-bond potentials (USE debye). It must be a positive number less then 1.0. |
| seed | I | - | N |
Seed for random number generation (default 0). |
| supdat | I | - | N |
Update frequency for energy print. |
| trace | F | - | N |
Distance potential scale factor used in the Gauss-Siedel distance geometry optimizer. See GSDG command. |