// Copyright (c) 2017-2022, Lawrence Livermore National Security, LLC and other CEED contributors.
// All Rights Reserved. See the top-level LICENSE and NOTICE files for details.
//
// SPDX-License-Identifier: BSD-2-Clause
//
// This file is part of CEED:  http://github.com/ceed

/// @file
/// libCEED QFunctions for mass operator example using PETSc

#ifndef bp1_h
#define bp1_h

#include <math.h>

// -----------------------------------------------------------------------------
// This QFunction sets up the geometric factors required to apply the
//   mass operator
//
// The quadrature data is stored in the array q_data.
//
// We require the determinant of the Jacobian to properly compute integrals of
//   the form: int( u v )
//
// Qdata: det_J * w
//
// -----------------------------------------------------------------------------
CEED_QFUNCTION(SetupMassGeo)(void *ctx, const CeedInt Q,
                             const CeedScalar *const *in,
                             CeedScalar *const *out) {
  const CeedScalar *J = in[1], *w = in[2]; // Note: *X = in[0]
  CeedScalar *q_data = out[0];

  // Quadrature Point Loop
  CeedPragmaSIMD
  for (CeedInt i=0; i<Q; i++) {
    const CeedScalar det_J = (J[i+Q*0]*(J[i+Q*4]*J[i+Q*8] - J[i+Q*5]*J[i+Q*7]) -
                             J[i+Q*1]*(J[i+Q*3]*J[i+Q*8] - J[i+Q*5]*J[i+Q*6]) +
                             J[i+Q*2]*(J[i+Q*3]*J[i+Q*7] - J[i+Q*4]*J[i+Q*6]));
    q_data[i] = det_J * w[i];
  } // End of Quadrature Point Loop
  return 0;
}

// -----------------------------------------------------------------------------
// This QFunction sets up the rhs and true solution for the problem
// -----------------------------------------------------------------------------
CEED_QFUNCTION(SetupMassRhs)(void *ctx, const CeedInt Q,
                             const CeedScalar *const *in,
                             CeedScalar *const *out) {
  const CeedScalar *x = in[0], *w = in[1];
  CeedScalar *true_soln = out[0], *rhs = out[1];

  // Quadrature Point Loop
  CeedPragmaSIMD
  for (CeedInt i=0; i<Q; i++) {
    true_soln[i] = sqrt(x[i]*x[i] + x[i+Q]*x[i+Q] + x[i+2*Q]*x[i+2*Q]);
    rhs[i] = w[i] * true_soln[i];
  } // End of Quadrature Point Loop
  return 0;
}

// -----------------------------------------------------------------------------
// This QFunction applies the mass operator for a scalar field.
//
// Inputs:
//   u     - Input vector at quadrature points
//   q_data - Geometric factors
//
// Output:
//   v     - Output vector (test functions) at quadrature points
//
// -----------------------------------------------------------------------------
CEED_QFUNCTION(Mass)(void *ctx, const CeedInt Q,
                     const CeedScalar *const *in, CeedScalar *const *out) {
  const CeedScalar *u = in[0], *q_data = in[1];
  CeedScalar *v = out[0];

  // Quadrature Point Loop
  CeedPragmaSIMD
  for (CeedInt i=0; i<Q; i++)
    v[i] = q_data[i] * u[i];

  return 0;
}
// -----------------------------------------------------------------------------

#endif // bp1_h