FixOrientation.cxx

// Copyright 2023, UChicago Argonne, LLC
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// Software Name: NEML2 -- the New Engineering material Model Library, version 2
// By: Argonne National Laboratory
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#include "neml2/models/solid_mechanics/crystal_plasticity/FixOrientation.h"
 
#include "neml2/tensors/tensors.h"
#include "neml2/misc/math.h"
 
namespace neml2
{
register_NEML2_object(FixOrientation);
 
OptionSet
FixOrientation::expected_options()
{
  OptionSet options = Model::expected_options();
 
  options.doc() =
      "Checks the value of the modified Rodrigues parameter by checking if "
      "\\f$ \\left\\lVert r \\right\\rVert > t \\f$, with \\f$ t \\f$ a threshold value set "
      "to 1.0 by default and replacing all the orientations that exceed this limit "
      "with their shadow parameters values.";
 
  options.set<VariableName>("input_orientation") = VariableName("state", "orientation");
  options.set("input_orientation").doc() = "Name of input tensor of orientations to operate on.";
 
  options.set<VariableName>("output_orientation") = VariableName("state", "orientation");
  options.set("output_orientation").doc() = "Name of output tensor";
 
  options.set<Real>("threshold") = 1.0;
  options.set("threshold").doc() = "Threshold value for translating to the shadow parameters";
 
  return options;
}
 
FixOrientation::FixOrientation(const OptionSet & options)
  : Model(options),
    _output(declare_output_variable<Rot>("output_orientation")),
    _input(declare_input_variable<Rot>("input_orientation")),
    _threshold(options.get<Real>("threshold"))
{
}
 
void
FixOrientation::set_value(bool out, bool dout_din, bool d2out_din2)
{
  neml_assert_dbg(!d2out_din2, "Second derivative not implemented.");
 
  if (out)
    _output = math::where(
        (Rot(_input).norm_sq() < _threshold).unsqueeze(-1), Rot(_input), Rot(_input).shadow());
 
  if (dout_din)
  {
    const auto I = R2::identity(options());
    _output.d(_input) = math::where(
        (Rot(_input).norm_sq() < _threshold).unsqueeze(-1).unsqueeze(-1), I, Rot(_input).dshadow());
  }
}
} // namespace neml2