/*
  Implements the Kokkos kernel
*/
#include <petscconf.h>
#if defined(PETSC_HAVE_CUDA_CLANG)
  #include <petsclandau.h>
  #define LANDAU_NOT_IMPLEMENTED SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Not supported with CLANG")
/*@C
  LandauKokkosJacobian - Kokkos backend for assembling the Landau collision-operator Jacobian for the `DMPlex` Landau time integrator

  Collective; No Fortran Support

  Level: developer

  Note:
  Called internally by the Landau operator setup; users go through `DMPlexLandauIJacobian()`.

.seealso: `DMPlexLandauCreateVelocitySpace()`, `DMPlexLandauIJacobian()`, `LandauKokkosStaticDataSet()`
@*/
PetscErrorCode LandauKokkosJacobian(DM[], const PetscInt, const PetscInt, const PetscInt, const PetscInt, const PetscInt[], PetscReal[], PetscScalar[], const PetscScalar[], const LandauStaticData *, const PetscReal, const PetscLogEvent[], const PetscInt[], const PetscInt[], Mat[], Mat)
{
  LANDAU_NOT_IMPLEMENTED;
}

/*@C
  LandauKokkosCreateMatMaps - Build the per-grid Kokkos-backed vertex maps used by the Landau collision operator

  Collective; No Fortran Support

  Level: developer

  Note:
  Called internally during Landau setup when the device backend is Kokkos.

.seealso: `LandauKokkosDestroyMatMaps()`, `DMPlexLandauCreateVelocitySpace()`
@*/
PetscErrorCode LandauKokkosCreateMatMaps(P4estVertexMaps *, pointInterpolationP4est (*)[LANDAU_MAX_Q_FACE], PetscInt[], PetscInt)
{
  LANDAU_NOT_IMPLEMENTED;
}

/*@C
  LandauKokkosDestroyMatMaps - Free the Kokkos-backed vertex maps created with `LandauKokkosCreateMatMaps()`

  Collective; No Fortran Support

  Level: developer

.seealso: `LandauKokkosCreateMatMaps()`
@*/
PetscErrorCode LandauKokkosDestroyMatMaps(P4estVertexMaps *, PetscInt)
{
  LANDAU_NOT_IMPLEMENTED;
}

/*@C
  LandauKokkosStaticDataSet - Copy precomputed Landau quadrature and species data to device-resident Kokkos views for use by `LandauKokkosJacobian()`

  Collective; No Fortran Support

  Level: developer

.seealso: `LandauKokkosStaticDataClear()`, `LandauKokkosJacobian()`
@*/
PetscErrorCode LandauKokkosStaticDataSet(DM, const PetscInt, const PetscInt, const PetscInt, const PetscInt, PetscInt[], PetscInt[], PetscInt[], PetscReal[], PetscReal[], PetscReal[], PetscReal[], PetscReal[], PetscReal[], PetscReal[], PetscReal[], PetscReal[], LandauStaticData *)
{
  LANDAU_NOT_IMPLEMENTED;
}

/*@C
  LandauKokkosStaticDataClear - Free the device-resident Kokkos data structures created with `LandauKokkosStaticDataSet()`

  Collective; No Fortran Support

  Level: developer

.seealso: `LandauKokkosStaticDataSet()`
@*/
PetscErrorCode LandauKokkosStaticDataClear(LandauStaticData *)
{
  LANDAU_NOT_IMPLEMENTED;
}
#else
  #include <petscvec_kokkos.hpp>
  #include <petsclandau.h>
  #include <petsc/private/dmpleximpl.h> /*I   "petscdmplex.h"   I*/
  #include <petsc/private/deviceimpl.h>
  #include <petscts.h>

  #include <Kokkos_Core.hpp>
  #include <cstdio>
typedef Kokkos::TeamPolicy<>::member_type team_member;
  #include "../land_tensors.h"

namespace landau_inner_red
{ // namespace helps with name resolution in reduction identity
template <class ScalarType>
struct array_type {
  ScalarType gg2[LANDAU_DIM];
  ScalarType gg3[LANDAU_DIM][LANDAU_DIM];

  KOKKOS_INLINE_FUNCTION // Default constructor - Initialize to 0's
  array_type()
  {
    for (int j = 0; j < LANDAU_DIM; j++) {
      gg2[j] = 0;
      for (int k = 0; k < LANDAU_DIM; k++) gg3[j][k] = 0;
    }
  }
  KOKKOS_INLINE_FUNCTION // Copy Constructor
  array_type(const array_type &rhs)
  {
    for (int j = 0; j < LANDAU_DIM; j++) {
      gg2[j] = rhs.gg2[j];
      for (int k = 0; k < LANDAU_DIM; k++) gg3[j][k] = rhs.gg3[j][k];
    }
  }
  KOKKOS_INLINE_FUNCTION // add operator
    array_type &operator+=(const array_type &src)
  {
    for (int j = 0; j < LANDAU_DIM; j++) {
      gg2[j] += src.gg2[j];
      for (int k = 0; k < LANDAU_DIM; k++) gg3[j][k] += src.gg3[j][k];
    }
    return *this;
  }
  KOKKOS_INLINE_FUNCTION // volatile add operator
    void operator+=(const volatile array_type &src) volatile
  {
    for (int j = 0; j < LANDAU_DIM; j++) {
      gg2[j] += src.gg2[j];
      for (int k = 0; k < LANDAU_DIM; k++) gg3[j][k] += src.gg3[j][k];
    }
  }
};
typedef array_type<PetscReal> TensorValueType; // used to simplify code below
} // namespace landau_inner_red

namespace Kokkos
{ //reduction identity must be defined in Kokkos namespace
template <>
struct reduction_identity<landau_inner_red::TensorValueType> {
  KOKKOS_FORCEINLINE_FUNCTION static landau_inner_red::TensorValueType sum() { return landau_inner_red::TensorValueType(); }
};
} // namespace Kokkos

extern "C" {
PetscErrorCode LandauKokkosCreateMatMaps(P4estVertexMaps maps[], pointInterpolationP4est (*pointMaps)[LANDAU_MAX_Q_FACE], PetscInt Nf[], PetscInt grid)
{
  P4estVertexMaps                                                                                                                                       h_maps; /* host container */
  const Kokkos::View<pointInterpolationP4est *[LANDAU_MAX_Q_FACE], Kokkos::LayoutRight, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>>     h_points((pointInterpolationP4est *)pointMaps, maps[grid].num_reduced);
  const Kokkos::View<LandauIdx *[LANDAU_MAX_SPECIES][LANDAU_MAX_NQND], Kokkos::LayoutRight, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_gidx((LandauIdx *)maps[grid].gIdx, maps[grid].num_elements);
  Kokkos::View<pointInterpolationP4est *[LANDAU_MAX_Q_FACE], Kokkos::LayoutRight>     *d_points = new Kokkos::View<pointInterpolationP4est *[LANDAU_MAX_Q_FACE], Kokkos::LayoutRight>("points", maps[grid].num_reduced);
  Kokkos::View<LandauIdx *[LANDAU_MAX_SPECIES][LANDAU_MAX_NQND], Kokkos::LayoutRight> *d_gidx   = new Kokkos::View<LandauIdx *[LANDAU_MAX_SPECIES][LANDAU_MAX_NQND], Kokkos::LayoutRight>("gIdx", maps[grid].num_elements);

  PetscFunctionBegin;
  Kokkos::deep_copy(*d_gidx, h_gidx);
  Kokkos::deep_copy(*d_points, h_points);
  h_maps.num_elements = maps[grid].num_elements;
  h_maps.num_face     = maps[grid].num_face;
  h_maps.num_reduced  = maps[grid].num_reduced;
  h_maps.deviceType   = maps[grid].deviceType;
  h_maps.numgrids     = maps[grid].numgrids;
  h_maps.Nf           = Nf[grid];
  h_maps.c_maps       = (pointInterpolationP4est(*)[LANDAU_MAX_Q_FACE])d_points->data();
  maps[grid].vp1      = (void *)d_points;
  h_maps.gIdx         = (LandauIdx(*)[LANDAU_MAX_SPECIES][LANDAU_MAX_NQND])d_gidx->data();
  maps[grid].vp2      = (void *)d_gidx;
  {
    Kokkos::View<P4estVertexMaps, Kokkos::HostSpace> h_maps_k(&h_maps);
    Kokkos::View<P4estVertexMaps>                   *d_maps_k = new Kokkos::View<P4estVertexMaps>(Kokkos::create_mirror(Kokkos::DefaultExecutionSpace::memory_space(), h_maps_k));
    Kokkos::deep_copy(*d_maps_k, h_maps_k);
    maps[grid].d_self = d_maps_k->data();
    maps[grid].vp3    = (void *)d_maps_k;
  }
  PetscFunctionReturn(PETSC_SUCCESS);
}
PetscErrorCode LandauKokkosDestroyMatMaps(P4estVertexMaps maps[], PetscInt num_grids)
{
  PetscFunctionBegin;
  for (PetscInt grid = 0; grid < num_grids; grid++) {
    auto a = static_cast<Kokkos::View<pointInterpolationP4est *[LANDAU_MAX_Q_FACE], Kokkos::LayoutRight> *>(maps[grid].vp1);
    auto b = static_cast<Kokkos::View<LandauIdx *[LANDAU_MAX_SPECIES][LANDAU_MAX_NQND], Kokkos::LayoutRight> *>(maps[grid].vp2);
    auto c = static_cast<Kokkos::View<P4estVertexMaps *> *>(maps[grid].vp3);
    delete a;
    delete b;
    delete c;
  }
  PetscFunctionReturn(PETSC_SUCCESS);
}

PetscErrorCode LandauKokkosStaticDataSet(DM plex, const PetscInt Nq, const PetscInt Nb, const PetscInt batch_sz, const PetscInt num_grids, PetscInt a_numCells[], PetscInt a_species_offset[], PetscInt a_mat_offset[], PetscReal a_nu_alpha[], PetscReal a_nu_beta[], PetscReal a_invMass[], PetscReal a_lambdas[], PetscReal a_invJ[], PetscReal a_x[], PetscReal a_y[], PetscReal a_z[], PetscReal a_w[], LandauStaticData *SData_d)
{
  PetscReal       *BB, *DD;
  PetscTabulation *Tf;
  PetscInt         dim;
  PetscInt         ip_offset[LANDAU_MAX_GRIDS + 1], ipf_offset[LANDAU_MAX_GRIDS + 1], elem_offset[LANDAU_MAX_GRIDS + 1], nip, IPf_sz, Nftot;
  PetscDS          prob;

  PetscFunctionBegin;
  PetscCall(DMGetDimension(plex, &dim));
  PetscCall(DMGetDS(plex, &prob));
  PetscCheck(LANDAU_DIM == dim, PETSC_COMM_WORLD, PETSC_ERR_PLIB, "dim %" PetscInt_FMT " != LANDAU_DIM %d", dim, LANDAU_DIM);
  PetscCall(PetscDSGetTabulation(prob, &Tf));
  BB           = Tf[0]->T[0];
  DD           = Tf[0]->T[1];
  ip_offset[0] = ipf_offset[0] = elem_offset[0] = 0;
  nip                                           = 0;
  IPf_sz                                        = 0;
  for (PetscInt grid = 0; grid < num_grids; grid++) {
    PetscInt nfloc        = a_species_offset[grid + 1] - a_species_offset[grid];
    elem_offset[grid + 1] = elem_offset[grid] + a_numCells[grid];
    nip += a_numCells[grid] * Nq;
    ip_offset[grid + 1] = nip;
    IPf_sz += Nq * nfloc * a_numCells[grid];
    ipf_offset[grid + 1] = IPf_sz;
  }
  Nftot = a_species_offset[num_grids];
  PetscCall(PetscKokkosInitializeCheck());
  {
    const Kokkos::View<PetscReal *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_alpha(a_nu_alpha, Nftot);
    auto                                                                                                            alpha = new Kokkos::View<PetscReal *, Kokkos::LayoutLeft>("alpha", Nftot);
    SData_d->alpha                                                                                                        = static_cast<void *>(alpha);
    const Kokkos::View<PetscReal *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_beta(a_nu_beta, Nftot);
    auto                                                                                                            beta = new Kokkos::View<PetscReal *, Kokkos::LayoutLeft>("beta", Nftot);
    SData_d->beta                                                                                                        = static_cast<void *>(beta);
    const Kokkos::View<PetscReal *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_invMass(a_invMass, Nftot);
    auto                                                                                                            invMass = new Kokkos::View<PetscReal *, Kokkos::LayoutLeft>("invMass", Nftot);
    SData_d->invMass                                                                                                        = static_cast<void *>(invMass);
    const Kokkos::View<PetscReal *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_lambdas(a_lambdas, LANDAU_MAX_GRIDS * LANDAU_MAX_GRIDS);
    auto                                                                                                            lambdas = new Kokkos::View<PetscReal *, Kokkos::LayoutLeft>("lambdas", LANDAU_MAX_GRIDS * LANDAU_MAX_GRIDS);
    SData_d->lambdas                                                                                                        = static_cast<void *>(lambdas);
    const Kokkos::View<PetscReal *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_BB(BB, Nq * Nb);
    auto                                                                                                            B = new Kokkos::View<PetscReal *, Kokkos::LayoutLeft>("B", Nq * Nb);
    SData_d->B                                                                                                        = static_cast<void *>(B);
    const Kokkos::View<PetscReal *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_DD(DD, Nq * Nb * dim);
    auto                                                                                                            D = new Kokkos::View<PetscReal *, Kokkos::LayoutLeft>("D", Nq * Nb * dim);
    SData_d->D                                                                                                        = static_cast<void *>(D);
    const Kokkos::View<PetscReal *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_invJ(a_invJ, nip * dim * dim);
    auto                                                                                                            invJ = new Kokkos::View<PetscReal *, Kokkos::LayoutLeft>("invJ", nip * dim * dim);
    SData_d->invJ                                                                                                        = static_cast<void *>(invJ);
    const Kokkos::View<PetscReal *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_x(a_x, nip);
    auto                                                                                                            x = new Kokkos::View<PetscReal *, Kokkos::LayoutLeft>("x", nip);
    SData_d->x                                                                                                        = static_cast<void *>(x);
    const Kokkos::View<PetscReal *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_y(a_y, nip);
    auto                                                                                                            y = new Kokkos::View<PetscReal *, Kokkos::LayoutLeft>("y", nip);
    SData_d->y                                                                                                        = static_cast<void *>(y);
    const Kokkos::View<PetscReal *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_w(a_w, nip);
    auto                                                                                                            w = new Kokkos::View<PetscReal *, Kokkos::LayoutLeft>("w", nip);
    SData_d->w                                                                                                        = static_cast<void *>(w);

    Kokkos::deep_copy(*alpha, h_alpha);
    Kokkos::deep_copy(*beta, h_beta);
    Kokkos::deep_copy(*invMass, h_invMass);
    Kokkos::deep_copy(*lambdas, h_lambdas);
    Kokkos::deep_copy(*B, h_BB);
    Kokkos::deep_copy(*D, h_DD);
    Kokkos::deep_copy(*invJ, h_invJ);
    Kokkos::deep_copy(*x, h_x);
    Kokkos::deep_copy(*y, h_y);
    Kokkos::deep_copy(*w, h_w);

    if (dim == 3) {
      const Kokkos::View<PetscReal *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_z(a_z, nip);
      auto                                                                                                            z = new Kokkos::View<PetscReal *, Kokkos::LayoutLeft>("z", nip);
      SData_d->z                                                                                                        = static_cast<void *>(z);
      Kokkos::deep_copy(*z, h_z);
    } else SData_d->z = NULL;

    //
    const Kokkos::View<PetscInt *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_NCells(a_numCells, num_grids);
    auto                                                                                                           nc = new Kokkos::View<PetscInt *, Kokkos::LayoutLeft>("NCells", num_grids);
    SData_d->NCells                                                                                                   = static_cast<void *>(nc);
    Kokkos::deep_copy(*nc, h_NCells);

    const Kokkos::View<PetscInt *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_species_offset(a_species_offset, num_grids + 1);
    auto                                                                                                           soff = new Kokkos::View<PetscInt *, Kokkos::LayoutLeft>("species_offset", num_grids + 1);
    SData_d->species_offset                                                                                             = static_cast<void *>(soff);
    Kokkos::deep_copy(*soff, h_species_offset);

    const Kokkos::View<PetscInt *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_mat_offset(a_mat_offset, num_grids + 1);
    auto                                                                                                           moff = new Kokkos::View<PetscInt *, Kokkos::LayoutLeft>("mat_offset", num_grids + 1);
    SData_d->mat_offset                                                                                                 = static_cast<void *>(moff);
    Kokkos::deep_copy(*moff, h_mat_offset);

    const Kokkos::View<PetscInt *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_ip_offset(ip_offset, num_grids + 1);
    auto                                                                                                           ipoff = new Kokkos::View<PetscInt *, Kokkos::LayoutLeft>("ip_offset", num_grids + 1);
    SData_d->ip_offset                                                                                                   = static_cast<void *>(ipoff);
    Kokkos::deep_copy(*ipoff, h_ip_offset);

    const Kokkos::View<PetscInt *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_elem_offset(elem_offset, num_grids + 1);
    auto                                                                                                           eoff = new Kokkos::View<PetscInt *, Kokkos::LayoutLeft>("elem_offset", num_grids + 1);
    SData_d->elem_offset                                                                                                = static_cast<void *>(eoff);
    Kokkos::deep_copy(*eoff, h_elem_offset);

    const Kokkos::View<PetscInt *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_ipf_offset(ipf_offset, num_grids + 1);
    auto                                                                                                           ipfoff = new Kokkos::View<PetscInt *, Kokkos::LayoutLeft>("ipf_offset", num_grids + 1);
    SData_d->ipf_offset                                                                                                   = static_cast<void *>(ipfoff);
    Kokkos::deep_copy(*ipfoff, h_ipf_offset);
  #if defined(LANDAU_LAYOUT_LEFT) // preallocate dynamic data, no copy
    auto ipfdf_data = new Kokkos::View<PetscReal ***, Kokkos::LayoutLeft>("fdf", batch_sz, dim + 1, IPf_sz);
  #else
    auto ipfdf_data = new Kokkos::View<PetscReal ***, Kokkos::LayoutRight>("fdf", batch_sz, dim + 1, IPf_sz);
  #endif
    SData_d->ipfdf_data = static_cast<void *>(ipfdf_data);
    auto Eq_m           = new Kokkos::View<PetscReal *, Kokkos::LayoutLeft>("Eq_m", Nftot); // allocate but do not set, same for whole batch
    SData_d->Eq_m       = static_cast<void *>(Eq_m);
    const Kokkos::View<LandauIdx *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_coo_elem_offsets((LandauIdx *)SData_d->coo_elem_offsets, SData_d->coo_n_cellsTot + 1);
    auto                                                                                                            coo_elem_offsets = new Kokkos::View<LandauIdx *, Kokkos::LayoutLeft>("coo_elem_offsets", SData_d->coo_n_cellsTot + 1);
    const Kokkos::View<LandauIdx *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_coo_elem_fullNb((LandauIdx *)SData_d->coo_elem_fullNb, SData_d->coo_n_cellsTot);
    auto                                                                                                            coo_elem_fullNb = new Kokkos::View<LandauIdx *, Kokkos::LayoutLeft>("coo_elem_offsets", SData_d->coo_n_cellsTot);
    const Kokkos::View<LandauIdx *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_coo_elem_point_offsets((LandauIdx *)SData_d->coo_elem_point_offsets, SData_d->coo_n_cellsTot * (LANDAU_MAX_NQND + 1));
    auto coo_elem_point_offsets = new Kokkos::View<LandauIdx *, Kokkos::LayoutLeft>("coo_elem_point_offsets", SData_d->coo_n_cellsTot * (LANDAU_MAX_NQND + 1));
    // assign & copy
    Kokkos::deep_copy(*coo_elem_offsets, h_coo_elem_offsets);
    Kokkos::deep_copy(*coo_elem_fullNb, h_coo_elem_fullNb);
    Kokkos::deep_copy(*coo_elem_point_offsets, h_coo_elem_point_offsets);
    // need to free this now and use pointer space
    PetscCall(PetscFree3(SData_d->coo_elem_offsets, SData_d->coo_elem_fullNb, SData_d->coo_elem_point_offsets));
    SData_d->coo_elem_offsets       = static_cast<void *>(coo_elem_offsets);
    SData_d->coo_elem_fullNb        = static_cast<void *>(coo_elem_fullNb);
    SData_d->coo_elem_point_offsets = static_cast<void *>(coo_elem_point_offsets);
    auto coo_vals                   = new Kokkos::View<PetscScalar *, Kokkos::LayoutRight, Kokkos::DefaultExecutionSpace>("coo_vals", SData_d->coo_size);
    SData_d->coo_vals               = static_cast<void *>(coo_vals);
  }
  SData_d->maps = NULL; // not used
  PetscFunctionReturn(PETSC_SUCCESS);
}

PetscErrorCode LandauKokkosStaticDataClear(LandauStaticData *SData_d)
{
  PetscFunctionBegin;
  if (SData_d->alpha) {
    auto alpha = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->alpha);
    delete alpha;
    SData_d->alpha = NULL;
    auto beta      = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->beta);
    delete beta;
    auto invMass = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->invMass);
    delete invMass;
    auto lambdas = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->lambdas);
    delete lambdas;
    auto B = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->B);
    delete B;
    auto D = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->D);
    delete D;
    auto invJ = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->invJ);
    delete invJ;
    auto x = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->x);
    delete x;
    auto y = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->y);
    delete y;
    if (SData_d->z) {
      auto z = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->z);
      delete z;
    }
  #if defined(LANDAU_LAYOUT_LEFT) // preallocate dynamic data, no copy
    auto z = static_cast<Kokkos::View<PetscReal ***, Kokkos::LayoutLeft> *>(SData_d->ipfdf_data);
  #else
    auto z = static_cast<Kokkos::View<PetscReal ***, Kokkos::LayoutRight> *>(SData_d->ipfdf_data);
  #endif
    delete z;
    auto w = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->w);
    delete w;
    auto Eq_m = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->Eq_m);
    delete Eq_m;
    // offset
    auto nc = static_cast<Kokkos::View<PetscInt *, Kokkos::LayoutLeft> *>(SData_d->NCells);
    delete nc;
    auto soff = static_cast<Kokkos::View<PetscInt *, Kokkos::LayoutLeft> *>(SData_d->species_offset);
    delete soff;
    auto moff = static_cast<Kokkos::View<PetscInt *, Kokkos::LayoutLeft> *>(SData_d->mat_offset);
    delete moff;
    auto ipoff = static_cast<Kokkos::View<PetscInt *, Kokkos::LayoutLeft> *>(SData_d->ip_offset);
    delete ipoff;
    auto eoff = static_cast<Kokkos::View<PetscInt *, Kokkos::LayoutLeft> *>(SData_d->elem_offset);
    delete eoff;
    auto ipfoff = static_cast<Kokkos::View<PetscInt *, Kokkos::LayoutLeft> *>(SData_d->ipf_offset);
    delete ipfoff;
    auto coo_elem_offsets = static_cast<Kokkos::View<LandauIdx *, Kokkos::LayoutLeft> *>((void *)SData_d->coo_elem_offsets);
    delete coo_elem_offsets;
    auto coo_elem_fullNb = static_cast<Kokkos::View<LandauIdx *, Kokkos::LayoutLeft> *>((void *)SData_d->coo_elem_fullNb);
    delete coo_elem_fullNb;
    auto coo_elem_point_offsets = static_cast<Kokkos::View<LandauIdx *, Kokkos::LayoutLeft> *>((void *)SData_d->coo_elem_point_offsets);
    delete coo_elem_point_offsets;
    SData_d->coo_elem_offsets       = NULL;
    SData_d->coo_elem_point_offsets = NULL;
    SData_d->coo_elem_fullNb        = NULL;
    auto coo_vals                   = static_cast<Kokkos::View<PetscScalar *, Kokkos::LayoutRight, Kokkos::DefaultExecutionSpace> *>((void *)SData_d->coo_vals);
    delete coo_vals;
  }
  PetscFunctionReturn(PETSC_SUCCESS);
}

  #define KOKKOS_SHARED_LEVEL 0   // 0 is shared, 1 is global

KOKKOS_INLINE_FUNCTION
PetscErrorCode landau_mat_assemble(PetscScalar *coo_vals, const PetscScalar Aij, const PetscInt f, const PetscInt g, const PetscInt Nb, PetscInt moffset, const PetscInt elem, const PetscInt fieldA, const P4estVertexMaps *d_maps, const LandauIdx coo_elem_offsets[], const LandauIdx coo_elem_fullNb[], const LandauIdx (*coo_elem_point_offsets)[LANDAU_MAX_NQND + 1], const PetscInt glb_elem_idx, const PetscInt bid_coo_sz_batch)
{
  PetscInt               idx, q, nr, nc;
  const LandauIdx *const Idxs                         = &d_maps->gIdx[elem][fieldA][0];
  PetscScalar            row_scale[LANDAU_MAX_Q_FACE] = {0}, col_scale[LANDAU_MAX_Q_FACE] = {0};
  { // mirror (i,j) in CreateStaticGPUData
    const int fullNb = coo_elem_fullNb[glb_elem_idx], fullNb2 = fullNb * fullNb;
    idx = Idxs[f];
    if (idx >= 0) {
      nr           = 1;
      row_scale[0] = 1.;
    } else {
      idx = -idx - 1;
      for (q = 0, nr = 0; q < d_maps->num_face; q++, nr++) {
        if (d_maps->c_maps[idx][q].gid < 0) break;
        row_scale[q] = d_maps->c_maps[idx][q].scale;
      }
    }
    idx = Idxs[g];
    if (idx >= 0) {
      nc           = 1;
      col_scale[0] = 1.;
    } else {
      idx = -idx - 1;
      nc  = d_maps->num_face;
      for (q = 0, nc = 0; q < d_maps->num_face; q++, nc++) {
        if (d_maps->c_maps[idx][q].gid < 0) break;
        col_scale[q] = d_maps->c_maps[idx][q].scale;
      }
    }
    const int idx0 = bid_coo_sz_batch + coo_elem_offsets[glb_elem_idx] + fieldA * fullNb2 + fullNb * coo_elem_point_offsets[glb_elem_idx][f] + nr * coo_elem_point_offsets[glb_elem_idx][g];
    for (int q = 0, idx2 = idx0; q < nr; q++) {
      for (int d = 0; d < nc; d++, idx2++) coo_vals[idx2] = row_scale[q] * col_scale[d] * Aij;
    }
  }
  return PETSC_SUCCESS;
}

PetscErrorCode LandauKokkosJacobian(DM plex[], const PetscInt Nq, const PetscInt Nb, const PetscInt batch_sz, const PetscInt num_grids, const PetscInt a_numCells[], PetscReal a_Eq_m[], PetscScalar a_elem_closure[], const PetscScalar a_xarray[], const LandauStaticData *SData_d, const PetscReal shift, const PetscLogEvent events[], const PetscInt a_mat_offset[], const PetscInt a_species_offset[], Mat subJ[], Mat JacP)
{
  using scr_mem_t   = Kokkos::DefaultExecutionSpace::scratch_memory_space;
  using real2_scr_t = Kokkos::View<PetscScalar **, Kokkos::LayoutRight, scr_mem_t>;
  using g2_scr_t    = Kokkos::View<PetscReal ***, Kokkos::LayoutRight, scr_mem_t>;
  using g3_scr_t    = Kokkos::View<PetscReal ****, Kokkos::LayoutRight, scr_mem_t>;
  PetscInt         dim, num_cells_max, Nf_max, num_cells_batch;
  int              nfaces = 0, vector_size = 256 / Nq;
  LandauCtx       *ctx;
  PetscReal       *d_Eq_m     = NULL;
  PetscScalar     *d_vertex_f = NULL;
  P4estVertexMaps *maps[LANDAU_MAX_GRIDS]; // this gets captured
  PetscContainer   container;
  const int        conc = Kokkos::DefaultExecutionSpace().concurrency(), openmp = !!(conc < 1000), team_size = (openmp == 0) ? Nq : 1;
  const PetscInt   coo_sz_batch = SData_d->coo_size / batch_sz;                                                 // capture
  auto             d_alpha_k    = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->alpha); //static data
  const PetscReal *d_alpha      = d_alpha_k->data();
  const PetscInt   Nftot        = d_alpha_k->size(); // total number of species
  auto             d_beta_k     = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->beta);
  const PetscReal *d_beta       = d_beta_k->data();
  auto             d_invMass_k  = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->invMass);
  const PetscReal *d_invMass    = d_invMass_k->data();
  auto             d_lambdas_k  = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->lambdas);
  const PetscReal *d_lambdas    = d_lambdas_k->data();
  auto             d_B_k        = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->B);
  const PetscReal *d_BB         = d_B_k->data();
  auto             d_D_k        = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->D);
  const PetscReal *d_DD         = d_D_k->data();
  auto             d_invJ_k     = *static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->invJ); // use Kokkos vector in kernels
  auto             d_x_k        = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->x);     //static data
  const PetscReal *d_x          = d_x_k->data();
  auto             d_y_k        = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->y); //static data
  const PetscReal *d_y          = d_y_k->data();
  auto             d_z_k        = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->z); //static data
  const PetscReal *d_z          = (LANDAU_DIM == 3) ? d_z_k->data() : NULL;
  auto             d_w_k        = *static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->w); //static data
  const PetscReal *d_w          = d_w_k.data();
  // grid offsets - single vertex grid data
  auto            d_numCells_k       = static_cast<Kokkos::View<PetscInt *, Kokkos::LayoutLeft> *>(SData_d->NCells);
  const PetscInt *d_numCells         = d_numCells_k->data();
  auto            d_species_offset_k = static_cast<Kokkos::View<PetscInt *, Kokkos::LayoutLeft> *>(SData_d->species_offset);
  const PetscInt *d_species_offset   = d_species_offset_k->data();
  auto            d_mat_offset_k     = static_cast<Kokkos::View<PetscInt *, Kokkos::LayoutLeft> *>(SData_d->mat_offset);
  const PetscInt *d_mat_offset       = d_mat_offset_k->data();
  auto            d_ip_offset_k      = static_cast<Kokkos::View<PetscInt *, Kokkos::LayoutLeft> *>(SData_d->ip_offset);
  const PetscInt *d_ip_offset        = d_ip_offset_k->data();
  auto            d_ipf_offset_k     = static_cast<Kokkos::View<PetscInt *, Kokkos::LayoutLeft> *>(SData_d->ipf_offset);
  const PetscInt *d_ipf_offset       = d_ipf_offset_k->data();
  auto            d_elem_offset_k    = static_cast<Kokkos::View<PetscInt *, Kokkos::LayoutLeft> *>(SData_d->elem_offset);
  const PetscInt *d_elem_offset      = d_elem_offset_k->data();
  #if defined(LANDAU_LAYOUT_LEFT) // preallocate dynamic data, including batched vertices
  Kokkos::View<PetscReal ***, Kokkos::LayoutLeft> d_fdf_k = *static_cast<Kokkos::View<PetscReal ***, Kokkos::LayoutLeft> *>(SData_d->ipfdf_data);
  #else
  Kokkos::View<PetscReal ***, Kokkos::LayoutRight> d_fdf_k = *static_cast<Kokkos::View<PetscReal ***, Kokkos::LayoutRight> *>(SData_d->ipfdf_data);
  #endif
  auto d_Eq_m_k = static_cast<Kokkos::View<PetscReal *, Kokkos::LayoutLeft> *>(SData_d->Eq_m); // static storage, dynamic data - E(t), copy later, single vertex
  // COO
  auto       d_coo_elem_offsets_k                           = static_cast<Kokkos::View<LandauIdx *, Kokkos::LayoutLeft> *>(SData_d->coo_elem_offsets);
  LandauIdx *d_coo_elem_offsets                             = (SData_d->coo_size == 0) ? NULL : d_coo_elem_offsets_k->data();
  auto       d_coo_elem_fullNb_k                            = static_cast<Kokkos::View<LandauIdx *, Kokkos::LayoutLeft> *>(SData_d->coo_elem_fullNb);
  LandauIdx *d_coo_elem_fullNb                              = (SData_d->coo_size == 0) ? NULL : d_coo_elem_fullNb_k->data();
  auto       d_coo_elem_point_offsets_k                     = static_cast<Kokkos::View<LandauIdx *, Kokkos::LayoutLeft> *>(SData_d->coo_elem_point_offsets);
  LandauIdx(*d_coo_elem_point_offsets)[LANDAU_MAX_NQND + 1] = (SData_d->coo_size == 0) ? NULL : (LandauIdx(*)[LANDAU_MAX_NQND + 1]) d_coo_elem_point_offsets_k->data();
  auto         d_coo_vals_k                                 = static_cast<Kokkos::View<PetscScalar *, Kokkos::LayoutRight> *>(SData_d->coo_vals);
  PetscScalar *d_coo_vals                                   = (SData_d->coo_size == 0) ? NULL : d_coo_vals_k->data();

  PetscFunctionBegin;
  while (vector_size & (vector_size - 1)) vector_size = vector_size & (vector_size - 1);
  if (vector_size > 16) vector_size = 16; // printf("DEBUG\n");
  PetscCall(PetscLogEventBegin(events[3], 0, 0, 0, 0));
  PetscCall(DMGetApplicationContext(plex[0], &ctx));
  PetscCheck(ctx, PETSC_COMM_SELF, PETSC_ERR_PLIB, "no context");
  PetscCall(DMGetDimension(plex[0], &dim));
  PetscCheck(LANDAU_DIM == dim, PETSC_COMM_WORLD, PETSC_ERR_PLIB, "dim %" PetscInt_FMT " != LANDAU_DIM %d", dim, LANDAU_DIM);
  if (ctx->gpu_assembly) {
    PetscCall(PetscObjectQuery((PetscObject)JacP, "assembly_maps", (PetscObject *)&container));
    PetscCheck(container, PETSC_COMM_SELF, PETSC_ERR_PLIB, "GPU assembly but no metadata in container");
    P4estVertexMaps *h_maps = NULL;
    PetscCall(PetscContainerGetPointer(container, &h_maps));
    for (PetscInt grid = 0; grid < num_grids; grid++) {
      PetscCheck(h_maps[grid].d_self, PETSC_COMM_SELF, PETSC_ERR_PLIB, "GPU assembly but no metadata in container");
      maps[grid] = h_maps[grid].d_self;
      nfaces     = h_maps[grid].num_face; // nface=0 for CPU assembly
    }
    PetscCheck(d_coo_vals, PETSC_COMM_SELF, PETSC_ERR_PLIB, "d_coo_vals==0");
  } else {
    for (PetscInt grid = 0; grid < num_grids; grid++) maps[grid] = NULL;
    nfaces    = 0;
    container = NULL;
  }
  num_cells_batch = Nf_max = num_cells_max = 0;
  for (PetscInt grid = 0; grid < num_grids; grid++) {
    int Nfloc = a_species_offset[grid + 1] - a_species_offset[grid];
    if (Nfloc > Nf_max) Nf_max = Nfloc;
    if (a_numCells[grid] > num_cells_max) num_cells_max = a_numCells[grid];
    num_cells_batch += a_numCells[grid]; // we don't have a host element offset here (but in ctx)
  }
  const int elem_mat_num_cells_max_grid = container ? 0 : num_cells_max;
  #ifdef LAND_SUPPORT_CPU_ASS
  const int                                           totDim_max = Nf_max * Nb, elem_mat_size_max = totDim_max * totDim_max;
  Kokkos::View<PetscScalar ****, Kokkos::LayoutRight> d_elem_mats("element matrices", batch_sz, num_grids, elem_mat_num_cells_max_grid, elem_mat_size_max); // not used (cpu assembly)
  #endif
  const Kokkos::View<PetscReal *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_Eq_m_k(a_Eq_m, Nftot);
  if (a_elem_closure || a_xarray) {
    Kokkos::deep_copy(*d_Eq_m_k, h_Eq_m_k);
    d_Eq_m = d_Eq_m_k->data();
  } else d_Eq_m = NULL;
  PetscCall(PetscKokkosInitializeCheck());
  PetscCall(PetscLogEventEnd(events[3], 0, 0, 0, 0));
  if (a_elem_closure || a_xarray) { // Jacobian, create f & df
    Kokkos::View<PetscScalar *, Kokkos::LayoutLeft> *d_vertex_f_k = NULL;
    PetscCall(PetscLogEventBegin(events[1], 0, 0, 0, 0));
    if (a_elem_closure) {
      PetscInt closure_sz = 0; // argh, don't have this on the host!!!
      for (PetscInt grid = 0; grid < num_grids; grid++) {
        PetscInt nfloc = a_species_offset[grid + 1] - a_species_offset[grid];
        closure_sz += Nb * nfloc * a_numCells[grid];
      }
      closure_sz *= batch_sz;
      d_vertex_f_k = new Kokkos::View<PetscScalar *, Kokkos::LayoutLeft>("closure", closure_sz);
      const Kokkos::View<PetscScalar *, Kokkos::LayoutLeft, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_closure_k(a_elem_closure, closure_sz); // Vertex data for each element
      Kokkos::deep_copy(*d_vertex_f_k, h_closure_k);
      d_vertex_f = d_vertex_f_k->data();
    } else {
      d_vertex_f = (PetscScalar *)a_xarray;
    }
    PetscCall(PetscLogEventEnd(events[1], 0, 0, 0, 0));
    PetscCall(PetscLogEventBegin(events[8], 0, 0, 0, 0));
    PetscCall(PetscLogGpuTimeBegin());

    const int scr_bytes_fdf = real2_scr_t::shmem_size(Nf_max, Nb);
    PetscCall(PetscInfo(plex[0], "df & f shared memory size: %d bytes in level, %d num cells total=%d, team size=%d, vector size=%d, #face=%d, Nf_max=%d\n", scr_bytes_fdf, KOKKOS_SHARED_LEVEL, (int)(num_cells_batch * batch_sz), team_size, vector_size, nfaces, (int)Nf_max));
    Kokkos::parallel_for(
      "f, df", Kokkos::TeamPolicy<>(num_cells_batch * batch_sz, team_size, vector_size).set_scratch_size(KOKKOS_SHARED_LEVEL, Kokkos::PerTeam(scr_bytes_fdf)), KOKKOS_LAMBDA(const team_member team) {
        const PetscInt b_Nelem = d_elem_offset[num_grids], b_elem_idx = team.league_rank() % b_Nelem, b_id = team.league_rank() / b_Nelem, IPf_sz_glb = d_ipf_offset[num_grids];
        // find my grid
        PetscInt grid = 0;
        while (b_elem_idx >= d_elem_offset[grid + 1]) grid++;
        {
          const PetscInt loc_nip = d_numCells[grid] * Nq, loc_Nf = d_species_offset[grid + 1] - d_species_offset[grid], loc_elem = b_elem_idx - d_elem_offset[grid];
          const PetscInt moffset = LAND_MOFFSET(b_id, grid, batch_sz, num_grids, d_mat_offset);
          {
            real2_scr_t      s_coef_k(team.team_scratch(KOKKOS_SHARED_LEVEL), Nf_max, Nb);
            PetscScalar     *coef;
            const PetscReal *invJe = &d_invJ_k((d_ip_offset[grid] + loc_elem * Nq) * dim * dim);
            // un pack IPData
            if (!maps[grid]) {
              coef = &d_vertex_f[b_id * IPf_sz_glb + d_ipf_offset[grid] + loc_elem * Nb * loc_Nf]; // closure and IP indexing are the same
            } else {
              coef = s_coef_k.data();
              Kokkos::parallel_for(Kokkos::TeamThreadRange(team, 0, (int)loc_Nf), [=](int f) {
                //for (int f = 0; f < loc_Nf; ++f) {
                Kokkos::parallel_for(Kokkos::ThreadVectorRange(team, 0, (int)Nb), [=](int b) {
                  //for (int b = 0; b < Nb; ++b) {
                  LandauIdx idx = maps[grid]->gIdx[loc_elem][f][b];
                  if (idx >= 0) {
                    coef[f * Nb + b] = d_vertex_f[idx + moffset]; // xarray data, not IP, need raw array to deal with CPU assemble case (not used)
                  } else {
                    idx              = -idx - 1;
                    coef[f * Nb + b] = 0;
                    for (int q = 0; q < maps[grid]->num_face; q++) {
                      PetscInt    id    = maps[grid]->c_maps[idx][q].gid;
                      PetscScalar scale = maps[grid]->c_maps[idx][q].scale;
                      if (id >= 0) coef[f * Nb + b] += scale * d_vertex_f[id + moffset];
                    }
                  }
                });
              });
            }
            team.team_barrier();
            Kokkos::parallel_for(Kokkos::TeamThreadRange(team, 0, Nq), [=](int myQi) {
              const PetscReal *const invJ = &invJe[myQi * dim * dim]; // b_elem_idx: batch element index
              const PetscReal       *Bq = &d_BB[myQi * Nb], *Dq = &d_DD[myQi * Nb * dim];
              Kokkos::parallel_for(Kokkos::ThreadVectorRange(team, 0, (int)loc_Nf), [=](int f) {
                PetscInt       b, e, d;
                PetscReal      refSpaceDer[LANDAU_DIM];
                const PetscInt idx    = d_ipf_offset[grid] + f * loc_nip + loc_elem * Nq + myQi;
                d_fdf_k(b_id, 0, idx) = 0.0;
                for (d = 0; d < LANDAU_DIM; ++d) refSpaceDer[d] = 0.0;
                for (b = 0; b < Nb; ++b) {
                  d_fdf_k(b_id, 0, idx) += Bq[b] * PetscRealPart(coef[f * Nb + b]);
                  for (d = 0; d < dim; ++d) refSpaceDer[d] += Dq[b * dim + d] * PetscRealPart(coef[f * Nb + b]);
                }
                for (d = 0; d < dim; ++d) {
                  for (e = 0, d_fdf_k(b_id, d + 1, idx) = 0.0; e < dim; ++e) d_fdf_k(b_id, d + 1, idx) += invJ[e * dim + d] * refSpaceDer[e];
                }
              }); // f
            });   // myQi
          }
          team.team_barrier();
        } // 'grid' scope
      }); // global elems - fdf
    Kokkos::fence();
    PetscCall(PetscLogGpuTimeEnd());
    PetscCall(PetscLogEventEnd(events[8], 0, 0, 0, 0));
    // Jacobian
    size_t      maximum_shared_mem_size = 64000;
    PetscDevice device;

    PetscCall(PetscDeviceGetDefault_Internal(&device));
    PetscCall(PetscDeviceGetAttribute(device, PETSC_DEVICE_ATTR_SIZE_T_SHARED_MEM_PER_BLOCK, &maximum_shared_mem_size));
    size_t    jac_scr_bytes    = (size_t)2 * (g2_scr_t::shmem_size(dim, Nf_max, Nq) + g3_scr_t::shmem_size(dim, dim, Nf_max, Nq));
    const int jac_shared_level = (jac_scr_bytes > maximum_shared_mem_size) ? 1 : KOKKOS_SHARED_LEVEL;
    // device function/lambda
    auto jac_lambda = KOKKOS_LAMBDA(const team_member team)
    {
      const PetscInt b_Nelem = d_elem_offset[num_grids], b_elem_idx = team.league_rank() % b_Nelem, b_id = team.league_rank() / b_Nelem;
      // find my grid
      PetscInt grid = 0;
      while (b_elem_idx >= d_elem_offset[grid + 1]) grid++;
      {
        const PetscInt loc_Nf = d_species_offset[grid + 1] - d_species_offset[grid], loc_elem = b_elem_idx - d_elem_offset[grid];
        const PetscInt moffset = LAND_MOFFSET(b_id, grid, batch_sz, num_grids, d_mat_offset);
        const PetscInt f_off   = d_species_offset[grid];
  #ifdef LAND_SUPPORT_CPU_ASS
        const PetscInt totDim = loc_Nf * Nb;
  #endif
        g2_scr_t g2(team.team_scratch(jac_shared_level), dim, loc_Nf, Nq);
        g3_scr_t g3(team.team_scratch(jac_shared_level), dim, dim, loc_Nf, Nq);
        g2_scr_t gg2(team.team_scratch(jac_shared_level), dim, loc_Nf, Nq);
        g3_scr_t gg3(team.team_scratch(jac_shared_level), dim, dim, loc_Nf, Nq);
        // get g2[] & g3[]
        Kokkos::parallel_for(Kokkos::TeamThreadRange(team, 0, Nq), [=](int myQi) {
          using Kokkos::parallel_reduce;
          const PetscInt                    jpidx_glb = d_ip_offset[grid] + loc_elem * Nq + myQi;
          const PetscReal                  *invJ      = &d_invJ_k(jpidx_glb * dim * dim);
          const PetscReal                   vj[3] = {d_x[jpidx_glb], d_y[jpidx_glb], d_z ? d_z[jpidx_glb] : 0}, wj = d_w[jpidx_glb];
          landau_inner_red::TensorValueType gg_temp; // reduce on part of gg2 and g33 for IP jpidx_g
          Kokkos::parallel_reduce(
            Kokkos::ThreadVectorRange(team, (int)d_ip_offset[num_grids]),
            [=](const int &ipidx, landau_inner_red::TensorValueType &ggg) {
              const PetscReal wi = d_w[ipidx], x = d_x[ipidx], y = d_y[ipidx];
              PetscReal       temp1[3] = {0, 0, 0}, temp2 = 0;
              PetscInt        fieldB, d2, d3, f_off_r, grid_r, ipidx_g, nip_loc_r, loc_Nf_r;
  #if LANDAU_DIM == 2
              PetscReal Ud[2][2], Uk[2][2], mask = (PetscAbs(vj[0] - x) < 100 * PETSC_SQRT_MACHINE_EPSILON && PetscAbs(vj[1] - y) < 100 * PETSC_SQRT_MACHINE_EPSILON) ? 0. : 1.;
              LandauTensor2D(vj, x, y, Ud, Uk, mask);
  #else
                PetscReal U[3][3], z = d_z[ipidx], mask = (PetscAbs(vj[0]-x) < 100*PETSC_SQRT_MACHINE_EPSILON && PetscAbs(vj[1]-y) < 100*PETSC_SQRT_MACHINE_EPSILON && PetscAbs(vj[2]-z) < 100*PETSC_SQRT_MACHINE_EPSILON) ? 0. : 1.;
                LandauTensor3D(vj, x, y, z, U, mask);
  #endif
              grid_r = 0;
              while (ipidx >= d_ip_offset[grid_r + 1]) grid_r++; // yuck search for grid
              f_off_r   = d_species_offset[grid_r];
              ipidx_g   = ipidx - d_ip_offset[grid_r];
              nip_loc_r = d_numCells[grid_r] * Nq;
              loc_Nf_r  = d_species_offset[grid_r + 1] - d_species_offset[grid_r];
              for (fieldB = 0; fieldB < loc_Nf_r; ++fieldB) { // fieldB is \beta  d_lambdas[grid][grid_r]
                const PetscInt  idx = d_ipf_offset[grid_r] + fieldB * nip_loc_r + ipidx_g;
                const PetscReal ff1 = d_beta[fieldB + f_off_r] * d_lambdas[LANDAU_MAX_GRIDS * grid + grid_r], ff2 = d_invMass[fieldB + f_off_r] * ff1;
                temp1[0] += d_fdf_k(b_id, 1, idx) * ff2;
                temp1[1] += d_fdf_k(b_id, 2, idx) * ff2;
  #if LANDAU_DIM == 3
                temp1[2] += d_fdf_k(b_id, 3, idx) * ff2;
  #endif
                temp2 += d_fdf_k(b_id, 0, idx) * ff1;
              }
              temp1[0] *= wi;
              temp1[1] *= wi;
  #if LANDAU_DIM == 3
              temp1[2] *= wi;
  #endif
              temp2 *= wi;
  #if LANDAU_DIM == 2
              for (d2 = 0; d2 < 2; d2++) {
                for (d3 = 0; d3 < 2; ++d3) {
                  /* K = U * grad(f): g2=e: i,A */
                  ggg.gg2[d2] += Uk[d2][d3] * temp1[d3];
                  /* D = -U * (I \kron (fx)): g3=f: i,j,A */
                  ggg.gg3[d2][d3] += Ud[d2][d3] * temp2;
                }
              }
  #else
                for (d2 = 0; d2 < 3; ++d2) {
                  for (d3 = 0; d3 < 3; ++d3) {
                    /* K = U * grad(f): g2 = e: i,A */
                    ggg.gg2[d2] += U[d2][d3]*temp1[d3];
                    /* D = -U * (I \kron (fx)): g3 = f: i,j,A */
                    ggg.gg3[d2][d3] += U[d2][d3]*temp2;
                  }
                }
  #endif
            },
            Kokkos::Sum<landau_inner_red::TensorValueType>(gg_temp));
          // add alpha and put in gg2/3
          Kokkos::parallel_for(Kokkos::ThreadVectorRange(team, (int)loc_Nf), [&](const int &fieldA) { // \alpha
            PetscInt d2, d3;
            for (d2 = 0; d2 < dim; d2++) {
              gg2(d2, fieldA, myQi) = gg_temp.gg2[d2] * d_alpha[fieldA + f_off];
              for (d3 = 0; d3 < dim; d3++) gg3(d2, d3, fieldA, myQi) = -gg_temp.gg3[d2][d3] * d_alpha[fieldA + f_off] * d_invMass[fieldA + f_off];
            }
          });
          /* add electric field term once per IP */
          Kokkos::parallel_for(Kokkos::ThreadVectorRange(team, (int)loc_Nf), [&](const int &fieldA) { gg2(dim - 1, fieldA, myQi) += d_Eq_m[fieldA + f_off]; });
          Kokkos::parallel_for(Kokkos::ThreadVectorRange(team, (int)loc_Nf), [=](const int &fieldA) {
            int d, d2, d3, dp;
            /* Jacobian transform - g2, g3 - per thread (2D) */
            for (d = 0; d < dim; ++d) {
              g2(d, fieldA, myQi) = 0;
              for (d2 = 0; d2 < dim; ++d2) {
                g2(d, fieldA, myQi) += invJ[d * dim + d2] * gg2(d2, fieldA, myQi);
                g3(d, d2, fieldA, myQi) = 0;
                for (d3 = 0; d3 < dim; ++d3) {
                  for (dp = 0; dp < dim; ++dp) g3(d, d2, fieldA, myQi) += invJ[d * dim + d3] * gg3(d3, dp, fieldA, myQi) * invJ[d2 * dim + dp];
                }
                g3(d, d2, fieldA, myQi) *= wj;
              }
              g2(d, fieldA, myQi) *= wj;
            }
          });
        }); // Nq
        team.team_barrier();
        { /* assemble */
          for (PetscInt fieldA = 0; fieldA < loc_Nf; fieldA++) {
            /* assemble */
            Kokkos::parallel_for(Kokkos::TeamThreadRange(team, 0, Nb), [=](int f) {
              Kokkos::parallel_for(Kokkos::ThreadVectorRange(team, 0, Nb), [=](int g) {
                PetscScalar t = 0;
                for (int qj = 0; qj < Nq; qj++) { // look at others integration points
                  const PetscReal *BJq = &d_BB[qj * Nb], *DIq = &d_DD[qj * Nb * dim];
                  for (int d = 0; d < dim; ++d) {
                    t += DIq[f * dim + d] * g2(d, fieldA, qj) * BJq[g];
                    for (int d2 = 0; d2 < dim; ++d2) t += DIq[f * dim + d] * g3(d, d2, fieldA, qj) * DIq[g * dim + d2];
                  }
                }
                if (elem_mat_num_cells_max_grid) { // CPU assembly
  #ifdef LAND_SUPPORT_CPU_ASS
                  const PetscInt fOff                     = (fieldA * Nb + f) * totDim + fieldA * Nb + g;
                  d_elem_mats(b_id, grid, loc_elem, fOff) = t;
  #endif
                } else {
                  static_cast<void>(landau_mat_assemble(d_coo_vals, t, f, g, Nb, moffset, loc_elem, fieldA, maps[grid], d_coo_elem_offsets, d_coo_elem_fullNb, d_coo_elem_point_offsets, b_elem_idx, b_id * coo_sz_batch));
                }
              });
            });
          }
        }
      } // scope with 'grid'
    };
  #if defined(PETSC_HAVE_HIP)
    const int lbound2 = 1;
  #else
    const int lbound2 = 2;
  #endif
    PetscCall(PetscLogEventBegin(events[4], 0, 0, 0, 0));
    PetscCall(PetscLogGpuTimeBegin());
    PetscCall(PetscInfo(plex[0], "Jacobian shared memory size: %zu bytes in level %s (max shared=%zu), num cells total=%d, team size=%d, vector size=%d, #face=%d, Nf_max=%d\n", jac_scr_bytes, jac_shared_level == 0 ? "local" : "global", maximum_shared_mem_size, (int)(num_cells_batch * batch_sz), team_size, vector_size, nfaces, (int)Nf_max));
    Kokkos::parallel_for("Jacobian", Kokkos::TeamPolicy<Kokkos::LaunchBounds<256, lbound2>>(num_cells_batch * batch_sz, team_size, vector_size).set_scratch_size(jac_shared_level, Kokkos::PerTeam(jac_scr_bytes)), jac_lambda);
    Kokkos::fence();
    PetscCall(PetscLogGpuTimeEnd());
    PetscCall(PetscLogEventEnd(events[4], 0, 0, 0, 0));
    if (d_vertex_f_k) delete d_vertex_f_k;
  } else { // mass
    PetscCall(PetscLogEventBegin(events[16], 0, 0, 0, 0));
    PetscCall(PetscLogGpuTimeBegin());
    PetscCall(PetscInfo(plex[0], "Mass team size=%d vector size=%d #face=%d Nb=%" PetscInt_FMT ", %s assembly\n", team_size, vector_size, nfaces, Nb, d_coo_vals ? "COO" : "CSR"));
    Kokkos::parallel_for(
      "Mass", Kokkos::TeamPolicy<>(num_cells_batch * batch_sz, team_size, vector_size), KOKKOS_LAMBDA(const team_member team) {
        const PetscInt b_Nelem = d_elem_offset[num_grids], b_elem_idx = team.league_rank() % b_Nelem, b_id = team.league_rank() / b_Nelem;
        // find my grid
        PetscInt grid = 0;
        while (b_elem_idx >= d_elem_offset[grid + 1]) grid++;
        {
          const PetscInt loc_Nf = d_species_offset[grid + 1] - d_species_offset[grid], loc_elem = b_elem_idx - d_elem_offset[grid], jpidx_0 = d_ip_offset[grid] + loc_elem * Nq;
  #ifdef LAND_SUPPORT_CPU_ASS
          const PetscInt totDim = loc_Nf * Nb;
  #endif
          const PetscInt moffset = LAND_MOFFSET(b_id, grid, batch_sz, num_grids, d_mat_offset);
          for (int fieldA = 0; fieldA < loc_Nf; fieldA++) {
            /* assemble */
            Kokkos::parallel_for(Kokkos::TeamThreadRange(team, 0, Nb), [=](int f) {
              Kokkos::parallel_for(Kokkos::ThreadVectorRange(team, 0, Nb), [=](int g) {
                PetscScalar t = 0;
                for (int qj = 0; qj < Nq; qj++) { // look at others integration points
                  const PetscReal *BJq       = &d_BB[qj * Nb];
                  const PetscInt   jpidx_glb = jpidx_0 + qj;
                  if (dim == 2) {
                    t += BJq[f] * d_w_k(jpidx_glb) * shift * BJq[g] * 2. * PETSC_PI;
                  } else {
                    t += BJq[f] * d_w_k(jpidx_glb) * shift * BJq[g];
                  }
                }
                if (elem_mat_num_cells_max_grid) {
  #ifdef LAND_SUPPORT_CPU_ASS
                  const PetscInt fOff                     = (fieldA * Nb + f) * totDim + fieldA * Nb + g;
                  d_elem_mats(b_id, grid, loc_elem, fOff) = t;
  #endif
                } else {
                  static_cast<void>(landau_mat_assemble(d_coo_vals, t, f, g, Nb, moffset, loc_elem, fieldA, maps[grid], d_coo_elem_offsets, d_coo_elem_fullNb, d_coo_elem_point_offsets, b_elem_idx, b_id * coo_sz_batch));
                }
              });
            });
          } // field
        } // grid
      });
    Kokkos::fence();
    PetscCall(PetscLogGpuTimeEnd());
    PetscCall(PetscLogEventEnd(events[16], 0, 0, 0, 0));
  }
  if (d_coo_vals) {
    PetscCall(MatSetValuesCOO(JacP, d_coo_vals, ADD_VALUES));
  #if !defined(LAND_SUPPORT_CPU_ASS)
    Kokkos::fence(); // for timers
  #endif
  } else if (elem_mat_num_cells_max_grid) { // CPU assembly
  #ifdef LAND_SUPPORT_CPU_ASS
    Kokkos::View<PetscScalar ****, Kokkos::LayoutRight>::HostMirror h_elem_mats = Kokkos::create_mirror_view(d_elem_mats);
    Kokkos::deep_copy(h_elem_mats, d_elem_mats);
    PetscCheck(!container, PETSC_COMM_SELF, PETSC_ERR_PLIB, "?????");
    for (PetscInt b_id = 0; b_id < batch_sz; b_id++) { // OpenMP (once)
      for (PetscInt grid = 0; grid < num_grids; grid++) {
        PetscSection       section, globalSection;
        PetscInt           cStart, cEnd;
        Mat                B       = subJ[LAND_PACK_IDX(b_id, grid)];
        PetscInt           moffset = LAND_MOFFSET(b_id, grid, batch_sz, num_grids, a_mat_offset), nloc, nzl, colbuf[1024], row;
        const PetscInt    *cols;
        const PetscScalar *vals;
        PetscCall(PetscLogEventBegin(events[5], 0, 0, 0, 0));
        PetscCall(DMPlexGetHeightStratum(plex[grid], 0, &cStart, &cEnd));
        PetscCall(DMGetLocalSection(plex[grid], &section));
        PetscCall(DMGetGlobalSection(plex[grid], &globalSection));
        PetscCall(PetscLogEventEnd(events[5], 0, 0, 0, 0));
        PetscCall(PetscLogEventBegin(events[6], 0, 0, 0, 0));
        for (PetscInt ej = cStart; ej < cEnd; ++ej) {
          const PetscScalar *elMat = &h_elem_mats(b_id, grid, ej - cStart, 0);
          PetscCall(DMPlexMatSetClosure(plex[grid], section, globalSection, B, ej, elMat, ADD_VALUES));
          if (grid == 0 && ej == -1) {
            const PetscInt loc_Nf = a_species_offset[grid + 1] - a_species_offset[grid], totDim = loc_Nf * Nb;
            int            d, f;
            PetscPrintf(PETSC_COMM_SELF, "Kokkos Element matrix %d/%d\n", 1, (int)a_numCells[grid]);
            for (d = 0; d < totDim; ++d) {
              for (f = 0; f < totDim; ++f) PetscPrintf(PETSC_COMM_SELF, " %12.5e", PetscRealPart(elMat[d * totDim + f]));
              PetscPrintf(PETSC_COMM_SELF, "\n");
            }
            exit(14);
          }
        }
        // move nest matrix to global JacP
        PetscCall(MatAssemblyBegin(B, MAT_FINAL_ASSEMBLY));
        PetscCall(MatAssemblyEnd(B, MAT_FINAL_ASSEMBLY));
        PetscCall(MatGetSize(B, &nloc, NULL));
        for (int i = 0; i < nloc; i++) {
          PetscCall(MatGetRow(B, i, &nzl, &cols, &vals));
          PetscCheck(nzl <= 1024, PetscObjectComm((PetscObject)B), PETSC_ERR_PLIB, "Row too big: %" PetscInt_FMT, nzl);
          for (int j = 0; j < nzl; j++) colbuf[j] = cols[j] + moffset;
          row = i + moffset;
          PetscCall(MatSetValues(JacP, 1, &row, nzl, colbuf, vals, ADD_VALUES));
          PetscCall(MatRestoreRow(B, i, &nzl, &cols, &vals));
        }
        PetscCall(MatDestroy(&subJ[LAND_PACK_IDX(b_id, grid)]));
        PetscCall(PetscLogEventEnd(events[6], 0, 0, 0, 0));
      } // grids
    }
  #else
    SETERRQ(PETSC_COMM_SELF, PETSC_ERR_PLIB, "CPU assembly not supported");
  #endif
  }
  PetscFunctionReturn(PETSC_SUCCESS);
}
} // extern "C"
#endif
