Syntax:
-compute ID group-ID coord/atom cutoff +compute ID group-ID coord/atom cutoff type1 type2 ...
Examples:
-compute 1 all coord/atom 2.0 +compute 1 all coord/atom 2.0 +compute 1 all coord/atom 6.0 1 2 +compute 1 all coord/atom 6.0 2*4 5*8 *Description:
-Define a computation that calculates the coordination number for each -atom in a group. +
Define a computation that calculates one or more coordination numbers +for each atom in a group.
-The value of the coordination number will be 0.0 for atoms not in the +
A coordination number is defined as the number of neighbor atoms with +specified atom type(s) that are within the specified cutoff distance +from the central atom. Atoms not in the group are included in a +coordination number of atoms in the group. +
+The typeN keywords allow you to specify which atom types contribute +to each coordination number. One coordination number is computed for +each of the typeN keywords listed. If no typeN keywords are +listed, a single coordination number is calculated, which includes +atoms of all types (same as the "*" format, see below). +
+The typeN keywords can be specified in one of two ways. An explicit +numeric value can be used, as in the 2nd example above. Or a +wild-card asterisk can be used to specify a range of atom types. This +takes the form "*" or "*n" or "n*" or "m*n". If N = the number of +atom types, then an asterisk with no numeric values means all types +from 1 to N. A leading asterisk means all types from 1 to n +(inclusive). A trailing asterisk means all types from n to N +(inclusive). A middle asterisk means all types from m to n +(inclusive). +
+The value of all coordination numbers will be 0.0 for atoms not in the specified compute group.
-The coordination number is defined as the number of neighbor atoms -within the specified cutoff distance from the central atom. Atoms not -in the group are included in the coordination number of atoms in the -group. -
The neighbor list needed to compute this quantity is constructed each time the calculation is performed (i.e. each time a snapshot of atoms is dumped). Thus it can be inefficient to compute/dump this quantity -too frequently or to have multiple compute/dump commands, each of a -coord/atom style. +too frequently.
Output info:
-This compute calculates a per-atom vector, which can be accessed by -any command that uses per-atom values from a compute as input. See -Section_howto 15 for an overview of -LAMMPS output options. +
If single type1 keyword is specified (or if none are specified), +this compute calculates a per-atom vector. If multiple typeN +keywords are specified, this compute calculates a per-atom array, with +N columns. These values can be accessed by any command that uses +per-atom values from a compute as input. See Section_howto +15 for an overview of LAMMPS output +options.
-The per-atom vector values will be a number >= 0.0, as explained -above. +
The per-atom vector or array values will be a number >= 0.0, as +explained above.
Restrictions: none
diff --git a/doc/compute_coord_atom.txt b/doc/compute_coord_atom.txt index 5fdbd9106e..c0b22bfabe 100644 --- a/doc/compute_coord_atom.txt +++ b/doc/compute_coord_atom.txt @@ -10,44 +10,65 @@ compute coord/atom command :h3 [Syntax:] -compute ID group-ID coord/atom cutoff :pre +compute ID group-ID coord/atom cutoff type1 type2 ... :pre ID, group-ID are documented in "compute"_compute.html command coord/atom = style name of this compute command -cutoff = distance within which to count coordination neighbors (distance units) :ul +cutoff = distance within which to count coordination neighbors (distance units) +typeN = atom type for Nth coordination count (see asterisk form below) :ul [Examples:] -compute 1 all coord/atom 2.0 :pre +compute 1 all coord/atom 2.0 +compute 1 all coord/atom 6.0 1 2 +compute 1 all coord/atom 6.0 2*4 5*8 * :pre [Description:] -Define a computation that calculates the coordination number for each -atom in a group. +Define a computation that calculates one or more coordination numbers +for each atom in a group. -The value of the coordination number will be 0.0 for atoms not in the +A coordination number is defined as the number of neighbor atoms with +specified atom type(s) that are within the specified cutoff distance +from the central atom. Atoms not in the group are included in a +coordination number of atoms in the group. + +The {typeN} keywords allow you to specify which atom types contribute +to each coordination number. One coordination number is computed for +each of the {typeN} keywords listed. If no {typeN} keywords are +listed, a single coordination number is calculated, which includes +atoms of all types (same as the "*" format, see below). + +The {typeN} keywords can be specified in one of two ways. An explicit +numeric value can be used, as in the 2nd example above. Or a +wild-card asterisk can be used to specify a range of atom types. This +takes the form "*" or "*n" or "n*" or "m*n". If N = the number of +atom types, then an asterisk with no numeric values means all types +from 1 to N. A leading asterisk means all types from 1 to n +(inclusive). A trailing asterisk means all types from n to N +(inclusive). A middle asterisk means all types from m to n +(inclusive). + +The value of all coordination numbers will be 0.0 for atoms not in the specified compute group. -The coordination number is defined as the number of neighbor atoms -within the specified cutoff distance from the central atom. Atoms not -in the group are included in the coordination number of atoms in the -group. - The neighbor list needed to compute this quantity is constructed each time the calculation is performed (i.e. each time a snapshot of atoms is dumped). Thus it can be inefficient to compute/dump this quantity -too frequently or to have multiple compute/dump commands, each of a -{coord/atom} style. +too frequently. [Output info:] -This compute calculates a per-atom vector, which can be accessed by -any command that uses per-atom values from a compute as input. See -"Section_howto 15"_Section_howto.html#howto_15 for an overview of -LAMMPS output options. +If single {type1} keyword is specified (or if none are specified), +this compute calculates a per-atom vector. If multiple {typeN} +keywords are specified, this compute calculates a per-atom array, with +N columns. These values can be accessed by any command that uses +per-atom values from a compute as input. See "Section_howto +15"_Section_howto.html#howto_15 for an overview of LAMMPS output +options. -The per-atom vector values will be a number >= 0.0, as explained -above. +The per-atom vector or array values will be a number >= 0.0, as +explained above. [Restrictions:] none