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Updating documentation, adding compute scalar

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jtclemm
2021-06-22 14:14:25 -06:00
parent 4a2d32ff6d
commit d5e5f590e8
3 changed files with 132 additions and 25 deletions
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doc/src/compute_fabric.rst
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@ -48,9 +48,15 @@ Description
"""""""""""
Define a compute that calculates various fabric tensors for pairwise
interactions :ref:`(Ouadfel) <Ouadfel>`. The *type* and *radius* settings
are used to select whether interactions cutoffs are determined by atom types
or by the sum of atomic radii (atom style sphere), respectively.
interaction :ref:`(Ouadfel) <Ouadfel>`. Fabric tensors are commonly used
to quantify the anisotropy or orientation of granular contacts but can also
be used to characterize the direction of pairwise interactions in general
systems. The *type* and *radius* settings are used to select whether interactions
cutoffs are determined by atom types or by the sum of atomic radii (atom
style sphere), respectively. Calling this compute is roughly the cost of a
pair style invocation as it involves a loop over the neighbor list. If the
normal or tangential force tensors are requested, it will be more expensive
than a pair style invocation as it will also recalculate all pair forces.
Four fabric tensors are available: the contact, branch, normal force, or
tangential force tensor. The contact tensor is calculated as
@ -137,17 +143,18 @@ Multiple *type/include* keywords may be added.
Output info
"""""""""""
This compute calculates a local vector of doubles. The vector stores the
This compute calculates a local vector of doubles and a scalar. The vector stores the
unique components of the first requested tensor in the order xx, yy, zz, xy, xz, yz
followed by the same components for all subsequent tensors. The final entry is the
followed by the same components for all subsequent tensors. The length of the vector
is therefore six times the number of requested tensors. The scalar output is the
number of pairwise interactions included in the calculation of the fabric tensor.
The length of the vector is therefore six times the number of requested tensors plus one.
Restrictions
""""""""""""
This fix is part of the GRANULAR package. It is only enabled if LAMMPS
was built with that package. See the :doc:`Build package <Build_package>` doc page for more info.
was built with that package. See the :doc:`Build package <Build_package>`
doc page for more info.
Currently, compute *fabric* does not support pair styles
with many-body interactions. It also does not