doc fix
This commit is contained in:
@ -12,15 +12,15 @@ Syntax
|
||||
|
||||
* ID, group-ID are documented in :doc:`compute <compute>` command
|
||||
* pace = style name of this compute command
|
||||
* ace_potential_filename = file name (in the .yace or .ace format from :doc:`pace pair_style <pair_pace>`) including ACE hyperparameters, bonds, and generalized coupling coefficients
|
||||
* ace_potential_filename = file name (in the .yace or .ace format from :doc:`pace pair_style <pair_pace>`) including ACE hyperparameters, bonds, and generalized coupling coefficients
|
||||
* keyword = *bikflag* or *dgradflag*
|
||||
|
||||
.. parsed-literal::
|
||||
|
||||
*bikflag* value = *0* or *1*
|
||||
*bikflag* value = *0* or *1*
|
||||
*0* = descriptors are summed over atoms of each type
|
||||
*1* = descriptors are listed separately for each atom
|
||||
*dgradflag* value = *0* or *1*
|
||||
*dgradflag* value = *0* or *1*
|
||||
*0* = descriptor gradients are summed over atoms of each type
|
||||
*1* = descriptor gradients are listed separately for each atom pair
|
||||
|
||||
@ -36,55 +36,55 @@ Examples
|
||||
Description
|
||||
"""""""""""
|
||||
|
||||
This compute calculates a set of quantities related to the atomic cluster
|
||||
expansion (ACE) descriptors of the atoms in a group. ACE descriptors are
|
||||
a highly generalizable atomic descriptor, encoding the radial and angular
|
||||
distribution of neighbor atoms, up to arbitrary bond order (rank). The
|
||||
detailed mathematical definition is given in the paper by
|
||||
:ref:`(Drautz) <Drautz19>`. These descriptors are used in the
|
||||
:doc:`pace pair_style <pair_pace>`. Quantities obtained from `compute pace`
|
||||
are related to those used in :doc:`pace pair_style <pair_pace>` to
|
||||
evaluate atomic energies, forces, and stresses for linear ACE models.
|
||||
This compute calculates a set of quantities related to the atomic cluster
|
||||
expansion (ACE) descriptors of the atoms in a group. ACE descriptors are
|
||||
a highly generalizable atomic descriptor, encoding the radial and angular
|
||||
distribution of neighbor atoms, up to arbitrary bond order (rank). The
|
||||
detailed mathematical definition is given in the paper by
|
||||
:ref:`(Drautz) <Drautz19>`. These descriptors are used in the
|
||||
:doc:`pace pair_style <pair_pace>`. Quantities obtained from `compute pace`
|
||||
are related to those used in :doc:`pace pair_style <pair_pace>` to
|
||||
evaluate atomic energies, forces, and stresses for linear ACE models.
|
||||
For example, the energy for a linear ACE model is calculated as:
|
||||
:math:`E=\sum_i^{N\_atoms} \sum_{\boldsymbol{\nu}} c_{\boldsymbol{\nu}} B_{i,\boldsymbol{\boldsymbol{\nu}}}`.
|
||||
The ACE descriptors for atom `i` :math:`B_{i,\boldsymbol{\nu}}`, and
|
||||
The ACE descriptors for atom `i` :math:`B_{i,\boldsymbol{\nu}}`, and
|
||||
:math:`c_{\nu}` are linear model parameters. The detailed definition
|
||||
and indexing convention for ACE descriptors is given in :ref:`(Drautz) <Drautz19>`.
|
||||
In short, body order :math:`N`, angular character, radial character,
|
||||
In short, body order :math:`N`, angular character, radial character,
|
||||
and chemical elements in the *N-body* descriptor are encoded by :math:`\nu`.
|
||||
In the :doc:`pace pair_style <pair_pace>`, the linear model parameters
|
||||
In the :doc:`pace pair_style <pair_pace>`, the linear model parameters
|
||||
and the ACE descriptors are combined for efficient evaluation of energies
|
||||
and forces. The details and benefits of this efficient implementation are
|
||||
and forces. The details and benefits of this efficient implementation are
|
||||
given in :ref:`(Lysogorskiy) <Lysogorskiy21>`. et. al, but the combined
|
||||
descriptors and linear model parameters for the purposes of `compute pace`
|
||||
may be expressed in terms of the ACE descriptors mentioned above.
|
||||
descriptors and linear model parameters for the purposes of `compute pace`
|
||||
may be expressed in terms of the ACE descriptors mentioned above.
|
||||
|
||||
:math:`c_{\boldsymbol{\nu}} B_{i,\boldsymbol{\nu}}= \sum_{\boldsymbol{\nu}' \in \boldsymbol{\nu} } \big[ c_{\boldsymbol{\nu}} C(\boldsymbol{\nu}') \big] A_{i,\boldsymbol{\nu}'}`
|
||||
|
||||
where the bracketed terms on the right-hand side are the combined functions
|
||||
with linear model parameters typically provided in the `<name>.yace` potential
|
||||
file for `pace pair_style`. When these bracketed terms are multiplied by the
|
||||
products of the atomic base from :ref:`(Drautz) <Drautz19>`,
|
||||
:math:`A_{i,\boldsymbol{\nu'}}`, the ACE descriptors are recovered but they
|
||||
file for `pace pair_style`. When these bracketed terms are multiplied by the
|
||||
products of the atomic base from :ref:`(Drautz) <Drautz19>`,
|
||||
:math:`A_{i,\boldsymbol{\nu'}}`, the ACE descriptors are recovered but they
|
||||
are also scaled by linear model parameters. The generalized coupling coefficients,
|
||||
written in short-hand here as :math:`C(\boldsymbol{\nu}')`, are the generalized
|
||||
written in short-hand here as :math:`C(\boldsymbol{\nu}')`, are the generalized
|
||||
Clebsch-Gordan or generalized Wigner symbols. It may be desirable to reverse the
|
||||
combination of these descriptors and the linear model parameters so that the
|
||||
ACE descriptors themselves may be used. The ACE descriptors and their gradients
|
||||
are often used when training ACE models, performing custom data analysis,
|
||||
ACE descriptors themselves may be used. The ACE descriptors and their gradients
|
||||
are often used when training ACE models, performing custom data analysis,
|
||||
generalizing ACE model forms, and other tasks that involve direct computation of
|
||||
descriptors. The key utility of `compute pace` is that it can compute the ACE
|
||||
descriptors and gradients so that these tasks can be performed during a LAMMPS
|
||||
simulation or so that LAMMPS can be used as a driver for tasks like ACE model
|
||||
parameterization. To see how this command can be used within a Python workflow
|
||||
to train ACE potentials, see the examples in
|
||||
`FitSNAP <https://github.com/FitSNAP/FitSNAP>`_. Examples on using outputs from
|
||||
descriptors. The key utility of `compute pace` is that it can compute the ACE
|
||||
descriptors and gradients so that these tasks can be performed during a LAMMPS
|
||||
simulation or so that LAMMPS can be used as a driver for tasks like ACE model
|
||||
parameterization. To see how this command can be used within a Python workflow
|
||||
to train ACE potentials, see the examples in
|
||||
`FitSNAP <https://github.com/FitSNAP/FitSNAP>`_. Examples on using outputs from
|
||||
this compute to construct general ACE potential forms are demonstrated in
|
||||
:ref:`(Goff) <Goff23>`. The various keywords and inputs to `compute pace`
|
||||
determine what ACE descriptors and related quantities are returned in a compute
|
||||
array.
|
||||
:ref:`(Goff) <Goff23>`. The various keywords and inputs to `compute pace`
|
||||
determine what ACE descriptors and related quantities are returned in a compute
|
||||
array.
|
||||
|
||||
The coefficient file, `<name>.yace`, ultimately defines the number of ACE
|
||||
The coefficient file, `<name>.yace`, ultimately defines the number of ACE
|
||||
descriptors to be computed, their maximum body-order, the degree of angular
|
||||
character they have, the degree of radial character they have, the chemical
|
||||
character (which element-element interactions are encoded by descriptors),
|
||||
@ -93,25 +93,25 @@ be modeled after the potential files in :doc:`pace pair_style <pair_pace>`,
|
||||
and have the same format. Details on how to generate the coefficient files
|
||||
to train ACE models may be found in `FitSNAP <https://github.com/FitSNAP/FitSNAP>`_.
|
||||
|
||||
The keyword *bikflag* determines whether or not to list the descriptors of
|
||||
each atom separately, or sum them together and list in a single row. If
|
||||
*bikflag* is set to *0* then a single descriptor row is used, which contains
|
||||
the per-atom ACE descriptors :math:`B_{i,\boldsymbol{\nu}}` summed over all
|
||||
atoms *i* to produce :math:`B_{\boldsymbol{\nu}}`. If *bikflag* is set to
|
||||
*1* this is replaced by a separate per-atom ACE descriptor row for each atom.
|
||||
The keyword *bikflag* determines whether or not to list the descriptors of
|
||||
each atom separately, or sum them together and list in a single row. If
|
||||
*bikflag* is set to *0* then a single descriptor row is used, which contains
|
||||
the per-atom ACE descriptors :math:`B_{i,\boldsymbol{\nu}}` summed over all
|
||||
atoms *i* to produce :math:`B_{\boldsymbol{\nu}}`. If *bikflag* is set to
|
||||
*1* this is replaced by a separate per-atom ACE descriptor row for each atom.
|
||||
In this case, the entries in the final column for these rows are set to zero.
|
||||
|
||||
The keyword *dgradflag* determines whether to sum atom gradients or list
|
||||
them separately. If *dgradflag* is set to 0, the ACE
|
||||
them separately. If *dgradflag* is set to 0, the ACE
|
||||
descriptor gradients w.r.t. atom *j* are summed over all atoms *i'*
|
||||
of, which may be useful when training linear ACE models on atomic forces.
|
||||
If *dgradflag* is set to 1, gradients are listed separately for each pair of atoms.
|
||||
Each row corresponds
|
||||
to a single term :math:`\frac{\partial {B_{i,\boldsymbol{\nu}}}}{\partial {r}^a_j}`
|
||||
where :math:`{r}^a_j` is the *a-th* position coordinate of the atom with global
|
||||
index *j*. This also changes the number of columns to be equal to the number of
|
||||
ACE descriptors, with 3 additional columns representing the indices :math:`i`,
|
||||
:math:`j`, and :math:`a`, as explained more in the Output info section below.
|
||||
index *j*. This also changes the number of columns to be equal to the number of
|
||||
ACE descriptors, with 3 additional columns representing the indices :math:`i`,
|
||||
:math:`j`, and :math:`a`, as explained more in the Output info section below.
|
||||
The option *dgradflag=1* requires that *bikflag=1*.
|
||||
|
||||
.. note::
|
||||
@ -122,17 +122,17 @@ The option *dgradflag=1* requires that *bikflag=1*.
|
||||
the value of the descriptor will not be returned in the `compute` array,
|
||||
but instead, the energy contribution from that descriptor will be returned.
|
||||
Do not do this unless it is the desired behavior.
|
||||
*In short, you should not plug in a '.yace' for a pace potential into this
|
||||
compute to evaluate descriptors.*
|
||||
*In short, you should not plug in a '.yace' for a pace potential into this
|
||||
compute to evaluate descriptors.*
|
||||
|
||||
.. note::
|
||||
|
||||
*Generalized Clebsch-Gordan or Generalized Wigner symbols (with appropriate
|
||||
factors) must be used to evaluate ACE descriptors with this compute.* There
|
||||
*Generalized Clebsch-Gordan or Generalized Wigner symbols (with appropriate
|
||||
factors) must be used to evaluate ACE descriptors with this compute.* There
|
||||
are multiple ways to define the generalized coupling coefficients. Because
|
||||
of this, this compute will not revert your potential file to a coupling
|
||||
of this, this compute will not revert your potential file to a coupling
|
||||
coefficient file. Instead this compute allows the user to supply coupling
|
||||
coefficients that follow any convention.
|
||||
coefficients that follow any convention.
|
||||
|
||||
.. note::
|
||||
|
||||
|
||||
Reference in New Issue
Block a user