xref: /petsc/src/ts/utils/dmplexlandau/tutorials/ex2.c (revision 48a46eb9bd028bec07ec0f396b1a3abb43f14558)

static char help[] = "Runaway electron model with Landau collision operator\n\n";

#include <petscdmplex.h>
#include <petsclandau.h>
#include <petscts.h>
#include <petscds.h>
#include <petscdmcomposite.h>
#include "petsc/private/petscimpl.h"

#if defined(PETSC_HAVE_CUDA_NVTX)
#include <nvToolsExt.h>
#endif

/* data for runaway electron model */
typedef struct REctx_struct {
  PetscErrorCode (*test)(TS, Vec, PetscInt, PetscReal, PetscBool, LandauCtx *, struct REctx_struct *);
  PetscErrorCode (*impuritySrcRate)(PetscReal, PetscReal *, LandauCtx *);
  PetscErrorCode (*E)(Vec, Vec, PetscInt, PetscReal, LandauCtx *, PetscReal *);
  PetscReal T_cold;        /* temperature of newly ionized electrons and impurity ions */
  PetscReal ion_potential; /* ionization potential of impurity */
  PetscReal Ne_ion;        /* effective number of electrons shed in ioization of impurity */
  PetscReal Ez_initial;
  PetscReal L; /* inductance */
  Vec       X_0;
  PetscInt  imp_idx; /* index for impurity ionizing sink */
  PetscReal pulse_start;
  PetscReal pulse_width;
  PetscReal pulse_rate;
  PetscReal current_rate;
  PetscInt  plotIdx;
  PetscInt  plotStep;
  PetscInt  idx; /* cache */
  PetscReal j;   /* cache */
  PetscReal plotDt;
  PetscBool plotting;
  PetscBool use_spitzer_eta;
  PetscInt  print_period;
  PetscInt  grid_view_idx;
} REctx;

static const PetscReal kev_joul = 6.241506479963235e+15; /* 1/1000e */

#define RE_CUT 3.
/* < v, u_re * v * q > */
static void f0_j_re(PetscInt dim, PetscInt Nf, PetscInt NfAux, const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[], const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[], PetscReal t, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar *f0) {
  PetscReal n_e = PetscRealPart(u[0]);
  if (dim == 2) {
    if (x[1] > RE_CUT || x[1] < -RE_CUT) {                    /* simply a cutoff for REs. v_|| > 3 v(T_e) */
      *f0 = n_e * 2. * PETSC_PI * x[0] * x[1] * constants[0]; /* n * r * v_|| * q */
    } else {
      *f0 = 0;
    }
  } else {
    if (x[2] > RE_CUT || x[2] < -RE_CUT) { /* simply a cutoff for REs. v_|| > 3 v(T_e) */
      *f0 = n_e * x[2] * constants[0];
    } else {
      *f0 = 0;
    }
  }
}

/* sum < v, u*v*q > */
static void f0_jz_sum(PetscInt dim, PetscInt Nf, PetscInt NfAux, const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[], const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[], PetscReal t, const PetscReal x[], PetscInt numConstants, const PetscScalar q[], PetscScalar *f0) {
  PetscInt ii;
  f0[0] = 0;
  if (dim == 2) {
    for (ii = 0; ii < Nf; ii++) f0[0] += u[ii] * 2. * PETSC_PI * x[0] * x[1] * q[ii]; /* n * r * v_|| * q * v_0 */
  } else {
    for (ii = 0; ii < Nf; ii++) f0[0] += u[ii] * x[2] * q[ii]; /* n * v_|| * q  * v_0 */
  }
}

/* < v, n_e > */
static void f0_n(PetscInt dim, PetscInt Nf, PetscInt NfAux, const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[], const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[], PetscReal t, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar *f0) {
  PetscInt ii = (PetscInt)PetscRealPart(constants[0]);
  if (dim == 2) f0[0] = 2. * PETSC_PI * x[0] * u[ii];
  else { f0[0] = u[ii]; }
}

/* < v, n_e v_|| > */
static void f0_vz(PetscInt dim, PetscInt Nf, PetscInt NfAux, const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[], const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[], PetscReal t, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar *f0) {
  PetscInt ii = (PetscInt)PetscRealPart(constants[0]);
  if (dim == 2) f0[0] = u[ii] * 2. * PETSC_PI * x[0] * x[1]; /* n r v_|| */
  else { f0[0] = u[ii] * x[2]; /* n v_|| */ }
}

/* < v, n_e (v-shift) > */
static void f0_ve_shift(PetscInt dim, PetscInt Nf, PetscInt NfAux, const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[], const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[], PetscReal t, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar *f0) {
  PetscReal vz = numConstants > 0 ? PetscRealPart(constants[0]) : 0;
  if (dim == 2) *f0 = u[0] * 2. * PETSC_PI * x[0] * PetscSqrtReal(x[0] * x[0] + (x[1] - vz) * (x[1] - vz)); /* n r v */
  else { *f0 = u[0] * PetscSqrtReal(x[0] * x[0] + x[1] * x[1] + (x[2] - vz) * (x[2] - vz)); /* n v */ }
}

/* CalculateE - Calculate the electric field  */
/*  T        -- Electron temperature  */
/*  n        -- Electron density  */
/*  lnLambda --   */
/*  eps0     --  */
/*  E        -- output E, input \hat E */
static PetscReal CalculateE(PetscReal Tev, PetscReal n, PetscReal lnLambda, PetscReal eps0, PetscReal *E) {
  PetscReal c, e, m;

  PetscFunctionBegin;
  c = 299792458.0;
  e = 1.602176e-19;
  m = 9.10938e-31;
  if (1) {
    double Ec, Ehat = *E, betath = PetscSqrtReal(2 * Tev * e / (m * c * c)), j0 = Ehat * 7 / (PetscSqrtReal(2) * 2) * PetscPowReal(betath, 3) * n * e * c;
    Ec = n * lnLambda * PetscPowReal(e, 3) / (4 * PETSC_PI * PetscPowReal(eps0, 2) * m * c * c);
    *E = Ec;
    PetscPrintf(PETSC_COMM_WORLD, "CalculateE j0=%g Ec = %g\n", j0, Ec);
  } else {
    PetscReal Ed, vth;
    vth = PetscSqrtReal(8 * Tev * e / (m * PETSC_PI));
    Ed  = n * lnLambda * PetscPowReal(e, 3) / (4 * PETSC_PI * PetscPowReal(eps0, 2) * m * vth * vth);
    *E  = Ed;
  }
  PetscFunctionReturn(0);
}

static PetscReal Spitzer(PetscReal m_e, PetscReal e, PetscReal Z, PetscReal epsilon0, PetscReal lnLam, PetscReal kTe_joules) {
  PetscReal Fz = (1 + 1.198 * Z + 0.222 * Z * Z) / (1 + 2.966 * Z + 0.753 * Z * Z), eta;
  eta          = Fz * 4. / 3. * PetscSqrtReal(2. * PETSC_PI) * Z * PetscSqrtReal(m_e) * PetscSqr(e) * lnLam * PetscPowReal(4 * PETSC_PI * epsilon0, -2.) * PetscPowReal(kTe_joules, -1.5);
  return eta;
}

/*  */
static PetscErrorCode testNone(TS ts, Vec X, PetscInt stepi, PetscReal time, PetscBool islast, LandauCtx *ctx, REctx *rectx) {
  PetscFunctionBeginUser;
  PetscFunctionReturn(0);
}

/*  */
static PetscErrorCode testSpitzer(TS ts, Vec X, PetscInt stepi, PetscReal time, PetscBool islast, LandauCtx *ctx, REctx *rectx) {
  PetscInt          ii, nDMs;
  PetscDS           prob;
  static PetscReal  old_ratio = 1e10;
  TSConvergedReason reason;
  PetscReal         J, J_re, spit_eta, Te_kev = 0, E, ratio, Z, n_e, v, v2;
  PetscScalar       user[2] = {0., ctx->charges[0]}, q[LANDAU_MAX_SPECIES], tt[LANDAU_MAX_SPECIES], vz;
  PetscReal         dt;
  DM                pack, plexe = ctx->plex[0], plexi = (ctx->num_grids == 1) ? NULL : ctx->plex[1];
  Vec              *XsubArray;

  PetscFunctionBeginUser;
  PetscCheck(ctx->num_species == 2, PETSC_COMM_SELF, PETSC_ERR_PLIB, "ctx->num_species %" PetscInt_FMT " != 2", ctx->num_species);
  PetscCall(VecGetDM(X, &pack));
  PetscCheck(pack, PETSC_COMM_SELF, PETSC_ERR_PLIB, "no DM");
  PetscCall(DMCompositeGetNumberDM(pack, &nDMs));
  PetscCheck(nDMs == ctx->num_grids * ctx->batch_sz, PETSC_COMM_SELF, PETSC_ERR_PLIB, "nDMs != ctx->num_grids*ctx->batch_sz %" PetscInt_FMT " != %" PetscInt_FMT, nDMs, ctx->num_grids * ctx->batch_sz);
  PetscCall(PetscMalloc(sizeof(*XsubArray) * nDMs, &XsubArray));
  PetscCall(DMCompositeGetAccessArray(pack, X, nDMs, NULL, XsubArray)); // read only
  PetscCall(TSGetTimeStep(ts, &dt));
  /* get current for each grid */
  for (ii = 0; ii < ctx->num_species; ii++) q[ii] = ctx->charges[ii];
  PetscCall(DMGetDS(plexe, &prob));
  PetscCall(PetscDSSetConstants(prob, 2, &q[0]));
  PetscCall(PetscDSSetObjective(prob, 0, &f0_jz_sum));
  PetscCall(DMPlexComputeIntegralFEM(plexe, XsubArray[LAND_PACK_IDX(ctx->batch_view_idx, 0)], tt, NULL));
  J = -ctx->n_0 * ctx->v_0 * PetscRealPart(tt[0]);
  if (plexi) { // add first (only) ion
    PetscCall(DMGetDS(plexi, &prob));
    PetscCall(PetscDSSetConstants(prob, 1, &q[1]));
    PetscCall(PetscDSSetObjective(prob, 0, &f0_jz_sum));
    PetscCall(DMPlexComputeIntegralFEM(plexi, XsubArray[LAND_PACK_IDX(ctx->batch_view_idx, 1)], tt, NULL));
    J += -ctx->n_0 * ctx->v_0 * PetscRealPart(tt[0]);
  }
  /* get N_e */
  PetscCall(DMGetDS(plexe, &prob));
  PetscCall(PetscDSSetConstants(prob, 1, user));
  PetscCall(PetscDSSetObjective(prob, 0, &f0_n));
  PetscCall(DMPlexComputeIntegralFEM(plexe, XsubArray[LAND_PACK_IDX(ctx->batch_view_idx, 0)], tt, NULL));
  n_e = PetscRealPart(tt[0]) * ctx->n_0;
  /* Z */
  Z   = -ctx->charges[1] / ctx->charges[0];
  /* remove drift */
  if (0) {
    user[0] = 0; // electrons
    PetscCall(DMGetDS(plexe, &prob));
    PetscCall(PetscDSSetConstants(prob, 1, user));
    PetscCall(PetscDSSetObjective(prob, 0, &f0_vz));
    PetscCall(DMPlexComputeIntegralFEM(plexe, XsubArray[LAND_PACK_IDX(ctx->batch_view_idx, 0)], tt, NULL));
    vz = ctx->n_0 * PetscRealPart(tt[0]) / n_e; /* non-dimensional */
  } else vz = 0;
  /* thermal velocity */
  PetscCall(DMGetDS(plexe, &prob));
  PetscCall(PetscDSSetConstants(prob, 1, &vz));
  PetscCall(PetscDSSetObjective(prob, 0, &f0_ve_shift));
  PetscCall(DMPlexComputeIntegralFEM(plexe, XsubArray[LAND_PACK_IDX(ctx->batch_view_idx, 0)], tt, NULL));
  v        = ctx->n_0 * ctx->v_0 * PetscRealPart(tt[0]) / n_e;                                           /* remove number density to get velocity */
  v2       = PetscSqr(v);                                                                                /* use real space: m^2 / s^2 */
  Te_kev   = (v2 * ctx->masses[0] * PETSC_PI / 8) * kev_joul;                                            /* temperature in kev */
  spit_eta = Spitzer(ctx->masses[0], -ctx->charges[0], Z, ctx->epsilon0, ctx->lnLam, Te_kev / kev_joul); /* kev --> J (kT) */
  if (0) {
    PetscCall(DMGetDS(plexe, &prob));
    PetscCall(PetscDSSetConstants(prob, 1, q));
    PetscCall(PetscDSSetObjective(prob, 0, &f0_j_re));
    PetscCall(DMPlexComputeIntegralFEM(plexe, XsubArray[LAND_PACK_IDX(ctx->batch_view_idx, 0)], tt, NULL));
  } else tt[0] = 0;
  J_re = -ctx->n_0 * ctx->v_0 * PetscRealPart(tt[0]);
  PetscCall(DMCompositeRestoreAccessArray(pack, X, nDMs, NULL, XsubArray)); // read only
  PetscCall(PetscFree(XsubArray));

  if (rectx->use_spitzer_eta) {
    E = ctx->Ez = spit_eta * (rectx->j - J_re);
  } else {
    E        = ctx->Ez; /* keep real E */
    rectx->j = J;       /* cache */
  }

  ratio = E / J / spit_eta;
  if (stepi > 10 && !rectx->use_spitzer_eta && ((old_ratio - ratio < 1.e-6))) {
    rectx->pulse_start     = time + 0.98 * dt;
    rectx->use_spitzer_eta = PETSC_TRUE;
  }
  PetscCall(TSGetConvergedReason(ts, &reason));
  PetscCall(TSGetConvergedReason(ts, &reason));
  if ((rectx->plotting) || stepi == 0 || reason || rectx->pulse_start == time + 0.98 * dt) {
    PetscCall(PetscPrintf(ctx->comm, "testSpitzer: %4" PetscInt_FMT ") time=%11.4e n_e= %10.3e E= %10.3e J= %10.3e J_re= %10.3e %.3g%% Te_kev= %10.3e Z_eff=%g E/J to eta ratio= %g (diff=%g) %s %s spit_eta=%g\n", stepi, (double)time,
                          (double)(n_e / ctx->n_0), (double)ctx->Ez, (double)J, (double)J_re, (double)(100 * J_re / J), (double)Te_kev, (double)Z, (double)ratio, (double)(old_ratio - ratio), rectx->use_spitzer_eta ? "using Spitzer eta*J E" : "constant E", rectx->pulse_start != time + 0.98 * dt ? "normal" : "transition", (double)spit_eta));
    PetscCheck(rectx->pulse_start != (time + 0.98 * dt), PETSC_COMM_WORLD, PETSC_ERR_ARG_WRONG, "Spitzer complete ratio=%g", (double)ratio);
  }
  old_ratio = ratio;
  PetscFunctionReturn(0);
}

static const double ppp = 2;
static void         f0_0_diff_lp(PetscInt dim, PetscInt Nf, PetscInt NfAux, const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[], const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[], PetscReal t, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar *f0) {
          LandauCtx      *ctx   = (LandauCtx *)constants;
          REctx          *rectx = (REctx *)ctx->data;
          PetscInt        ii    = rectx->idx, i;
          const PetscReal kT_m  = ctx->k * ctx->thermal_temps[ii] / ctx->masses[ii]; /* kT/m */
          const PetscReal n     = ctx->n[ii];
          PetscReal       diff, f_maxwell, v2 = 0, theta = 2 * kT_m / (ctx->v_0 * ctx->v_0); /* theta = 2kT/mc^2 */
          for (i = 0; i < dim; ++i) v2 += x[i] * x[i];
  f_maxwell = n * PetscPowReal(PETSC_PI * theta, -1.5) * (PetscExpReal(-v2 / theta));
          diff      = 2. * PETSC_PI * x[0] * (PetscRealPart(u[ii]) - f_maxwell);
          f0[0]     = PetscPowReal(diff, ppp);
}
static void f0_0_maxwellian_lp(PetscInt dim, PetscInt Nf, PetscInt NfAux, const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[], const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[], PetscReal t, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar *f0) {
  LandauCtx      *ctx   = (LandauCtx *)constants;
  REctx          *rectx = (REctx *)ctx->data;
  PetscInt        ii    = rectx->idx, i;
  const PetscReal kT_m  = ctx->k * ctx->thermal_temps[ii] / ctx->masses[ii]; /* kT/m */
  const PetscReal n     = ctx->n[ii];
  PetscReal       f_maxwell, v2 = 0, theta = 2 * kT_m / (ctx->v_0 * ctx->v_0); /* theta = 2kT/mc^2 */
  for (i = 0; i < dim; ++i) v2 += x[i] * x[i];
  f_maxwell = 2. * PETSC_PI * x[0] * n * PetscPowReal(PETSC_PI * theta, -1.5) * (PetscExpReal(-v2 / theta));
  f0[0]     = PetscPowReal(f_maxwell, ppp);
}

/*  */
static PetscErrorCode testStable(TS ts, Vec X, PetscInt stepi, PetscReal time, PetscBool islast, LandauCtx *ctx, REctx *rectx) {
  PetscDS     prob;
  Vec         X2;
  PetscReal   ediff, idiff = 0, lpm0, lpm1 = 1;
  PetscScalar tt[LANDAU_MAX_SPECIES];
  DM          dm, plex = ctx->plex[0];

  PetscFunctionBeginUser;
  PetscCall(VecGetDM(X, &dm));
  PetscCall(DMGetDS(plex, &prob));
  PetscCall(VecDuplicate(X, &X2));
  PetscCall(VecCopy(X, X2));
  if (!rectx->X_0) {
    PetscCall(VecDuplicate(X, &rectx->X_0));
    PetscCall(VecCopy(X, rectx->X_0));
  }
  PetscCall(VecAXPY(X, -1.0, rectx->X_0));
  PetscCall(PetscDSSetConstants(prob, sizeof(LandauCtx) / sizeof(PetscScalar), (PetscScalar *)ctx));
  rectx->idx = 0;
  PetscCall(PetscDSSetObjective(prob, 0, &f0_0_diff_lp));
  PetscCall(DMPlexComputeIntegralFEM(plex, X2, tt, NULL));
  ediff = PetscPowReal(PetscRealPart(tt[0]), 1. / ppp);
  PetscCall(PetscDSSetObjective(prob, 0, &f0_0_maxwellian_lp));
  PetscCall(DMPlexComputeIntegralFEM(plex, X2, tt, NULL));
  lpm0 = PetscPowReal(PetscRealPart(tt[0]), 1. / ppp);
  if (ctx->num_species > 1) {
    rectx->idx = 1;
    PetscCall(PetscDSSetObjective(prob, 0, &f0_0_diff_lp));
    PetscCall(DMPlexComputeIntegralFEM(plex, X2, tt, NULL));
    idiff = PetscPowReal(PetscRealPart(tt[0]), 1. / ppp);
    PetscCall(PetscDSSetObjective(prob, 0, &f0_0_maxwellian_lp));
    PetscCall(DMPlexComputeIntegralFEM(plex, X2, tt, NULL));
    lpm1 = PetscPowReal(PetscRealPart(tt[0]), 1. / ppp);
  }
  PetscCall(PetscPrintf(PETSC_COMM_WORLD, "%s %" PetscInt_FMT ") time=%10.3e n-%d norm electrons/max=%20.13e ions/max=%20.13e\n", "----", stepi, (double)time, (int)ppp, (double)(ediff / lpm0), (double)(idiff / lpm1)));
  /* view */
  PetscCall(VecCopy(X2, X));
  PetscCall(VecDestroy(&X2));
  if (islast) {
    PetscCall(VecDestroy(&rectx->X_0));
    rectx->X_0 = NULL;
  }
  PetscFunctionReturn(0);
}

static PetscErrorCode EInduction(Vec X, Vec X_t, PetscInt step, PetscReal time, LandauCtx *ctx, PetscReal *a_E) {
  REctx      *rectx = (REctx *)ctx->data;
  PetscInt    ii;
  DM          dm, plex;
  PetscScalar tt[LANDAU_MAX_SPECIES], qv0[LANDAU_MAX_SPECIES];
  PetscReal   dJ_dt;
  PetscDS     prob;

  PetscFunctionBeginUser;
  for (ii = 0; ii < ctx->num_species; ii++) qv0[ii] = ctx->charges[ii] * ctx->v_0;
  PetscCall(VecGetDM(X, &dm));
  PetscCall(DMGetDS(dm, &prob));
  PetscCall(DMConvert(dm, DMPLEX, &plex));
  /* get d current / dt */
  PetscCall(PetscDSSetConstants(prob, ctx->num_species, qv0));
  PetscCall(PetscDSSetObjective(prob, 0, &f0_jz_sum));
  PetscCheck(X_t, PETSC_COMM_SELF, PETSC_ERR_PLIB, "X_t");
  PetscCall(DMPlexComputeIntegralFEM(plex, X_t, tt, NULL));
  dJ_dt = -ctx->n_0 * PetscRealPart(tt[0]) / ctx->t_0;
  /* E induction */
  *a_E  = -rectx->L * dJ_dt + rectx->Ez_initial;
  PetscCall(DMDestroy(&plex));
  PetscFunctionReturn(0);
}

static PetscErrorCode EConstant(Vec X, Vec X_t, PetscInt step, PetscReal time, LandauCtx *ctx, PetscReal *a_E) {
  PetscFunctionBeginUser;
  *a_E = ctx->Ez;
  PetscFunctionReturn(0);
}

static PetscErrorCode ENone(Vec X, Vec X_t, PetscInt step, PetscReal time, LandauCtx *ctx, PetscReal *a_E) {
  PetscFunctionBeginUser;
  *a_E = 0;
  PetscFunctionReturn(0);
}

/* ------------------------------------------------------------------- */
/*
   FormSource - Evaluates source terms F(t).

   Input Parameters:
.  ts - the TS context
.  time -
.  X_dummmy - input vector
.  dummy - optional user-defined context, as set by SNESSetFunction()

   Output Parameter:
.  F - function vector
 */
static PetscErrorCode FormSource(TS ts, PetscReal ftime, Vec X_dummmy, Vec F, void *dummy) {
  PetscReal  new_imp_rate;
  LandauCtx *ctx;
  DM         pack;
  REctx     *rectx;

  PetscFunctionBeginUser;
  PetscCall(TSGetDM(ts, &pack));
  PetscCall(DMGetApplicationContext(pack, &ctx));
  rectx = (REctx *)ctx->data;
  /* check for impurities */
  PetscCall(rectx->impuritySrcRate(ftime, &new_imp_rate, ctx));
  if (new_imp_rate != 0) {
    if (new_imp_rate != rectx->current_rate) {
      PetscInt  ii;
      PetscReal dne_dt, dni_dt, tilda_ns[LANDAU_MAX_SPECIES], temps[LANDAU_MAX_SPECIES];
      Vec       globFarray[LANDAU_MAX_GRIDS * LANDAU_MAX_BATCH_SZ];
      rectx->current_rate = new_imp_rate;
      for (ii = 1; ii < LANDAU_MAX_SPECIES; ii++) tilda_ns[ii] = 0;
      for (ii = 1; ii < LANDAU_MAX_SPECIES; ii++) temps[ii] = 1;
      dni_dt                   = new_imp_rate /* *ctx->t_0 */; /* fully ionized immediately, no normalize, stay in non-dim */
      dne_dt                   = new_imp_rate * rectx->Ne_ion /* *ctx->t_0 */;
      tilda_ns[0]              = dne_dt;
      tilda_ns[rectx->imp_idx] = dni_dt;
      temps[0]                 = rectx->T_cold;
      temps[rectx->imp_idx]    = rectx->T_cold;
      PetscCall(PetscInfo(ctx->plex[0], "\tHave new_imp_rate= %10.3e time= %10.3e de/dt= %10.3e di/dt= %10.3e ***\n", (double)new_imp_rate, (double)ftime, (double)dne_dt, (double)dni_dt));
      PetscCall(DMCompositeGetAccessArray(pack, F, ctx->num_grids * ctx->batch_sz, NULL, globFarray));
      for (PetscInt grid = 0; grid < ctx->num_grids; grid++) {
        /* add it */
        PetscCall(DMPlexLandauAddMaxwellians(ctx->plex[grid], globFarray[LAND_PACK_IDX(0, grid)], ftime, temps, tilda_ns, grid, 0, 1, ctx));
      }
      // Does DMCompositeRestoreAccessArray copy the data back? (no)
      PetscCall(DMCompositeRestoreAccessArray(pack, F, ctx->num_grids * ctx->batch_sz, NULL, globFarray));
    }
  } else {
    PetscCall(VecZeroEntries(F));
    rectx->current_rate = 0;
  }
  PetscFunctionReturn(0);
}

PetscErrorCode Monitor(TS ts, PetscInt stepi, PetscReal time, Vec X, void *actx) {
  LandauCtx        *ctx   = (LandauCtx *)actx; /* user-defined application context */
  REctx            *rectx = (REctx *)ctx->data;
  DM                pack  = NULL;
  Vec               globXArray[LANDAU_MAX_GRIDS * LANDAU_MAX_BATCH_SZ];
  TSConvergedReason reason;

  PetscFunctionBeginUser;
  PetscCall(TSGetConvergedReason(ts, &reason));
  if (rectx->grid_view_idx != -1 || (reason && ctx->verbose > 3)) {
    PetscCall(VecGetDM(X, &pack));
    PetscCall(DMCompositeGetAccessArray(pack, X, ctx->num_grids * ctx->batch_sz, NULL, globXArray));
  }
  if (stepi > rectx->plotStep && rectx->plotting) {
    rectx->plotting = PETSC_FALSE; /* was doing diagnostics, now done */
    rectx->plotIdx++;
  }
  /* view */
  if (time / rectx->plotDt >= (PetscReal)rectx->plotIdx || reason) {
    if ((reason || stepi == 0 || rectx->plotIdx % rectx->print_period == 0) && ctx->verbose > 1) {
      /* print norms */
      PetscCall(DMPlexLandauPrintNorms(X, stepi));
    }
    if (!rectx->plotting) { /* first step of possible backtracks */
      rectx->plotting = PETSC_TRUE;
      /* diagnostics + change E field with Sptizer (not just a monitor) */
      PetscCall(rectx->test(ts, X, stepi, time, reason ? PETSC_TRUE : PETSC_FALSE, ctx, rectx));
    } else {
      PetscPrintf(PETSC_COMM_WORLD, "\t\t ERROR SKIP test spit ------\n");
      rectx->plotting = PETSC_TRUE;
    }
    if (rectx->grid_view_idx != -1) {
      PetscCall(PetscObjectSetName((PetscObject)globXArray[LAND_PACK_IDX(ctx->batch_view_idx, rectx->grid_view_idx)], rectx->grid_view_idx == 0 ? "ue" : "ui"));
      /* view, overwrite step when back tracked */
      PetscCall(DMSetOutputSequenceNumber(ctx->plex[rectx->grid_view_idx], rectx->plotIdx, time * ctx->t_0));
      PetscCall(VecViewFromOptions(globXArray[LAND_PACK_IDX(ctx->batch_view_idx, rectx->grid_view_idx)], NULL, "-ex2_vec_view"));
    }
    rectx->plotStep = stepi;
  } else {
    if (rectx->plotting) PetscPrintf(PETSC_COMM_WORLD, " ERROR rectx->plotting=%s step %" PetscInt_FMT "\n", PetscBools[rectx->plotting], stepi);
    /* diagnostics + change E field with Sptizer (not just a monitor) - can we lag this? */
    PetscCall(rectx->test(ts, X, stepi, time, reason ? PETSC_TRUE : PETSC_FALSE, ctx, rectx));
  }
  /* parallel check that only works of all batches are identical */
  if (reason && ctx->verbose > 3) {
    PetscReal   val, rval;
    PetscMPIInt rank;
    PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
    for (PetscInt grid = 0; grid < ctx->num_grids; grid++) {
      PetscInt nerrors = 0;
      for (PetscInt i = 0; i < ctx->batch_sz; i++) {
        PetscCall(VecNorm(globXArray[LAND_PACK_IDX(i, grid)], NORM_2, &val));
        if (i == 0) rval = val;
        else if ((val = PetscAbs(val - rval) / rval) > 1000 * PETSC_MACHINE_EPSILON) {
          PetscCall(PetscPrintf(PETSC_COMM_SELF, " [%d] Warning %" PetscInt_FMT ".%" PetscInt_FMT ") diff = %2.15e\n", rank, grid, i, (double)val));
          nerrors++;
        }
      }
      if (nerrors) {
        PetscCall(PetscPrintf(PETSC_COMM_SELF, " ***** [%d] ERROR max %" PetscInt_FMT " errors\n", rank, nerrors));
      } else {
        PetscCall(PetscPrintf(PETSC_COMM_WORLD, "[%d] %" PetscInt_FMT ") batch consistency check OK\n", rank, grid));
      }
    }
  }
  rectx->idx = 0;
  if (rectx->grid_view_idx != -1 || (reason && ctx->verbose > 3)) PetscCall(DMCompositeRestoreAccessArray(pack, X, ctx->num_grids * ctx->batch_sz, NULL, globXArray));
  PetscFunctionReturn(0);
}

PetscErrorCode PreStep(TS ts) {
  LandauCtx *ctx;
  REctx     *rectx;
  DM         dm;
  PetscInt   stepi;
  PetscReal  time;
  Vec        X;

  PetscFunctionBeginUser;
  /* not used */
  PetscCall(TSGetDM(ts, &dm));
  PetscCall(TSGetTime(ts, &time));
  PetscCall(TSGetSolution(ts, &X));
  PetscCall(DMGetApplicationContext(dm, &ctx));
  rectx = (REctx *)ctx->data;
  PetscCall(TSGetStepNumber(ts, &stepi));
  /* update E */
  PetscCall(rectx->E(X, NULL, stepi, time, ctx, &ctx->Ez));
  PetscFunctionReturn(0);
}

/* model for source of non-ionized impurities, profile provided by model, in du/dt form in normalized units (tricky because n_0 is normalized with electrons) */
static PetscErrorCode stepSrc(PetscReal time, PetscReal *rho, LandauCtx *ctx) {
  REctx *rectx = (REctx *)ctx->data;

  PetscFunctionBeginUser;
  if (time >= rectx->pulse_start) *rho = rectx->pulse_rate;
  else *rho = 0.;
  PetscFunctionReturn(0);
}
static PetscErrorCode zeroSrc(PetscReal time, PetscReal *rho, LandauCtx *ctx) {
  PetscFunctionBeginUser;
  *rho = 0.;
  PetscFunctionReturn(0);
}
static PetscErrorCode pulseSrc(PetscReal time, PetscReal *rho, LandauCtx *ctx) {
  REctx *rectx = (REctx *)ctx->data;

  PetscFunctionBeginUser;
  PetscCheck(rectx->pulse_start != PETSC_MAX_REAL, PETSC_COMM_WORLD, PETSC_ERR_ARG_WRONG, "'-ex2_pulse_start_time X' must be used with '-ex2_impurity_source_type pulse'");
  if (time < rectx->pulse_start || time > rectx->pulse_start + 3 * rectx->pulse_width) *rho = 0;
  else {
    double x = PetscSinReal((time - rectx->pulse_start) / (3 * rectx->pulse_width) * 2 * PETSC_PI - PETSC_PI / 2) + 1; /* 0:2, integrates to 1.0 */
    *rho     = rectx->pulse_rate * x / (3 * rectx->pulse_width);
    if (!rectx->use_spitzer_eta) rectx->use_spitzer_eta = PETSC_TRUE; /* use it next time */
  }
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "ProcessREOptions"
static PetscErrorCode ProcessREOptions(REctx *rectx, const LandauCtx *ctx, DM dm, const char prefix[]) {
  PetscFunctionList plist = NULL, testlist = NULL, elist = NULL;
  char              pname[256], testname[256], ename[256];
  DM                dm_dummy;
  PetscBool         Connor_E = PETSC_FALSE;

  PetscFunctionBeginUser;
  PetscCall(DMCreate(PETSC_COMM_WORLD, &dm_dummy));
  rectx->Ne_ion          = 1;    /* number of electrons given up by impurity ion */
  rectx->T_cold          = .005; /* kev */
  rectx->ion_potential   = 15;   /* ev */
  rectx->L               = 2;
  rectx->X_0             = NULL;
  rectx->imp_idx         = ctx->num_species - 1; /* default ionized impurity as last one */
  rectx->pulse_start     = PETSC_MAX_REAL;
  rectx->pulse_width     = 1;
  rectx->plotStep        = PETSC_MAX_INT;
  rectx->pulse_rate      = 1.e-1;
  rectx->current_rate    = 0;
  rectx->plotIdx         = 0;
  rectx->j               = 0;
  rectx->plotDt          = 1.0;
  rectx->plotting        = PETSC_FALSE;
  rectx->use_spitzer_eta = PETSC_FALSE;
  rectx->idx             = 0;
  rectx->print_period    = 10;
  rectx->grid_view_idx   = -1; // do not get if not needed
  /* Register the available impurity sources */
  PetscCall(PetscFunctionListAdd(&plist, "step", &stepSrc));
  PetscCall(PetscFunctionListAdd(&plist, "none", &zeroSrc));
  PetscCall(PetscFunctionListAdd(&plist, "pulse", &pulseSrc));
  PetscCall(PetscStrcpy(pname, "none"));
  PetscCall(PetscFunctionListAdd(&testlist, "none", &testNone));
  PetscCall(PetscFunctionListAdd(&testlist, "spitzer", &testSpitzer));
  PetscCall(PetscFunctionListAdd(&testlist, "stable", &testStable));
  PetscCall(PetscStrcpy(testname, "none"));
  PetscCall(PetscFunctionListAdd(&elist, "none", &ENone));
  PetscCall(PetscFunctionListAdd(&elist, "induction", &EInduction));
  PetscCall(PetscFunctionListAdd(&elist, "constant", &EConstant));
  PetscCall(PetscStrcpy(ename, "constant"));

  PetscOptionsBegin(PETSC_COMM_SELF, prefix, "Options for Runaway/seed electron model", "none");
  PetscCall(PetscOptionsReal("-ex2_plot_dt", "Plotting interval", "ex2.c", rectx->plotDt, &rectx->plotDt, NULL));
  if (rectx->plotDt < 0) rectx->plotDt = 1e30;
  if (rectx->plotDt == 0) rectx->plotDt = 1e-30;
  PetscCall(PetscOptionsInt("-ex2_print_period", "Plotting interval", "ex2.c", rectx->print_period, &rectx->print_period, NULL));
  PetscCall(PetscOptionsInt("-ex2_grid_view_idx", "grid_view_idx", "ex2.c", rectx->grid_view_idx, &rectx->grid_view_idx, NULL));
  PetscCheck(rectx->grid_view_idx < ctx->num_grids || rectx->grid_view_idx == -1, PETSC_COMM_WORLD, PETSC_ERR_ARG_WRONG, "rectx->grid_view_idx (%" PetscInt_FMT ") >= ctx->num_grids (%" PetscInt_FMT ")", rectx->imp_idx, ctx->num_grids);
  PetscCall(PetscOptionsFList("-ex2_impurity_source_type", "Name of impurity source to run", "", plist, pname, pname, sizeof(pname), NULL));
  PetscCall(PetscOptionsFList("-ex2_test_type", "Name of test to run", "", testlist, testname, testname, sizeof(testname), NULL));
  PetscCall(PetscOptionsInt("-ex2_impurity_index", "index of sink for impurities", "none", rectx->imp_idx, &rectx->imp_idx, NULL));
  PetscCheck((rectx->imp_idx < ctx->num_species && rectx->imp_idx >= 1) || ctx->num_species <= 1, PETSC_COMM_WORLD, PETSC_ERR_ARG_WRONG, "index of sink for impurities ions is out of range (%" PetscInt_FMT "), must be > 0 && < NS", rectx->imp_idx);
  PetscCall(PetscOptionsFList("-ex2_e_field_type", "Electric field type", "", elist, ename, ename, sizeof(ename), NULL));
  rectx->Ne_ion = -ctx->charges[rectx->imp_idx] / ctx->charges[0];
  PetscCall(PetscOptionsReal("-ex2_t_cold", "Temperature of cold electron and ions after ionization in keV", "none", rectx->T_cold, &rectx->T_cold, NULL));
  PetscCall(PetscOptionsReal("-ex2_pulse_start_time", "Time at which pulse happens for 'pulse' source", "none", rectx->pulse_start, &rectx->pulse_start, NULL));
  PetscCall(PetscOptionsReal("-ex2_pulse_width_time", "Width of pulse 'pulse' source", "none", rectx->pulse_width, &rectx->pulse_width, NULL));
  PetscCall(PetscOptionsReal("-ex2_pulse_rate", "Number density of pulse for 'pulse' source", "none", rectx->pulse_rate, &rectx->pulse_rate, NULL));
  rectx->T_cold *= 1.16e7; /* convert to Kelvin */
  PetscCall(PetscOptionsReal("-ex2_ion_potential", "Potential to ionize impurity (should be array) in ev", "none", rectx->ion_potential, &rectx->ion_potential, NULL));
  PetscCall(PetscOptionsReal("-ex2_inductance", "Inductance E feild", "none", rectx->L, &rectx->L, NULL));
  PetscCall(PetscOptionsBool("-ex2_connor_e_field_units", "Scale Ex but Connor-Hastie E_c", "none", Connor_E, &Connor_E, NULL));
  PetscCall(PetscInfo(dm_dummy, "Num electrons from ions=%g, T_cold=%10.3e, ion potential=%10.3e, E_z=%10.3e v_0=%10.3e\n", (double)rectx->Ne_ion, (double)rectx->T_cold, (double)rectx->ion_potential, (double)ctx->Ez, (double)ctx->v_0));
  PetscOptionsEnd();
  /* get impurity source rate function */
  PetscCall(PetscFunctionListFind(plist, pname, &rectx->impuritySrcRate));
  PetscCheck(rectx->impuritySrcRate, PETSC_COMM_WORLD, PETSC_ERR_ARG_WRONG, "No impurity source function found '%s'", pname);
  PetscCall(PetscFunctionListFind(testlist, testname, &rectx->test));
  PetscCheck(rectx->test, PETSC_COMM_WORLD, PETSC_ERR_ARG_WRONG, "No test found '%s'", testname);
  PetscCall(PetscFunctionListFind(elist, ename, &rectx->E));
  PetscCheck(rectx->E, PETSC_COMM_WORLD, PETSC_ERR_ARG_WRONG, "No E field function found '%s'", ename);
  PetscCall(PetscFunctionListDestroy(&plist));
  PetscCall(PetscFunctionListDestroy(&testlist));
  PetscCall(PetscFunctionListDestroy(&elist));

  /* convert E from Connor-Hastie E_c units to real if doing Spitzer E */
  if (Connor_E) {
    PetscReal E = ctx->Ez, Tev = ctx->thermal_temps[0] * 8.621738e-5, n = ctx->n_0 * ctx->n[0];
    CalculateE(Tev, n, ctx->lnLam, ctx->epsilon0, &E);
    ((LandauCtx *)ctx)->Ez *= E;
  }
  PetscCall(DMDestroy(&dm_dummy));
  PetscFunctionReturn(0);
}

int main(int argc, char **argv) {
  DM         pack;
  Vec        X;
  PetscInt   dim = 2, nDMs;
  TS         ts;
  Mat        J;
  PetscDS    prob;
  LandauCtx *ctx;
  REctx     *rectx;
#if defined PETSC_USE_LOG
  PetscLogStage stage;
#endif
  PetscMPIInt rank;
#if defined(PETSC_HAVE_THREADSAFETY)
  double starttime, endtime;
#endif
  PetscFunctionBeginUser;
  PetscCall(PetscInitialize(&argc, &argv, NULL, help));
  PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
  if (rank) { /* turn off output stuff for duplicate runs */
    PetscCall(PetscOptionsClearValue(NULL, "-ex2_dm_view"));
    PetscCall(PetscOptionsClearValue(NULL, "-ex2_vec_view"));
    PetscCall(PetscOptionsClearValue(NULL, "-ex2_vec_view_init"));
    PetscCall(PetscOptionsClearValue(NULL, "-ex2_dm_view_init"));
    PetscCall(PetscOptionsClearValue(NULL, "-info")); /* this does not work */
  }
  PetscCall(PetscOptionsGetInt(NULL, NULL, "-dim", &dim, NULL));
  /* Create a mesh */
  PetscCall(DMPlexLandauCreateVelocitySpace(PETSC_COMM_WORLD, dim, "", &X, &J, &pack));
  PetscCall(DMCompositeGetNumberDM(pack, &nDMs));
  PetscCall(PetscObjectSetName((PetscObject)J, "Jacobian"));
  PetscCall(PetscObjectSetName((PetscObject)X, "f"));
  PetscCall(DMGetApplicationContext(pack, &ctx));
  PetscCall(DMSetUp(pack));
  /* context */
  PetscCall(PetscNew(&rectx));
  ctx->data = rectx;
  PetscCall(ProcessREOptions(rectx, ctx, pack, ""));
  PetscCall(DMGetDS(pack, &prob));
  if (rectx->grid_view_idx != -1) {
    Vec *XsubArray = NULL;
    PetscCall(PetscMalloc(sizeof(*XsubArray) * nDMs, &XsubArray));
    PetscCall(DMCompositeGetAccessArray(pack, X, nDMs, NULL, XsubArray)); // read only
    PetscCall(PetscObjectSetName((PetscObject)XsubArray[LAND_PACK_IDX(ctx->batch_view_idx, rectx->grid_view_idx)], rectx->grid_view_idx == 0 ? "ue" : "ui"));
    PetscCall(DMSetOutputSequenceNumber(ctx->plex[rectx->grid_view_idx], 0, 0.0));
    PetscCall(DMViewFromOptions(ctx->plex[rectx->grid_view_idx], NULL, "-ex2_dm_view"));
    PetscCall(DMViewFromOptions(ctx->plex[rectx->grid_view_idx], NULL, "-ex2_dm_view_init"));
    PetscCall(VecViewFromOptions(XsubArray[LAND_PACK_IDX(ctx->batch_view_idx, rectx->grid_view_idx)], NULL, "-ex2_vec_view"));      // initial condition (monitor plots after step)
    PetscCall(VecViewFromOptions(XsubArray[LAND_PACK_IDX(ctx->batch_view_idx, rectx->grid_view_idx)], NULL, "-ex2_vec_view_init")); // initial condition (monitor plots after step)
    PetscCall(DMCompositeRestoreAccessArray(pack, X, nDMs, NULL, XsubArray));                                                       // read only
    PetscCall(PetscFree(XsubArray));
  }
  /* Create timestepping solver context */
  PetscCall(TSCreate(PETSC_COMM_SELF, &ts));
  PetscCall(TSSetDM(ts, pack));
  PetscCall(TSSetIFunction(ts, NULL, DMPlexLandauIFunction, NULL));
  PetscCall(TSSetIJacobian(ts, J, J, DMPlexLandauIJacobian, NULL));
  PetscCall(TSSetRHSFunction(ts, NULL, FormSource, NULL));
  PetscCall(TSSetFromOptions(ts));
  PetscCall(TSSetSolution(ts, X));
  PetscCall(TSSetApplicationContext(ts, ctx));
  PetscCall(TSMonitorSet(ts, Monitor, ctx, NULL));
  PetscCall(TSSetPreStep(ts, PreStep));
  rectx->Ez_initial = ctx->Ez; /* cache for induction caclulation - applied E field */
  if (1) {                     /* warm up an test just DMPlexLandauIJacobian */
    Vec       vec;
    PetscInt  nsteps;
    PetscReal dt;
    PetscCall(PetscLogStageRegister("Warmup", &stage));
    PetscCall(PetscLogStagePush(stage));
    PetscCall(VecDuplicate(X, &vec));
    PetscCall(VecCopy(X, vec));
    PetscCall(TSGetMaxSteps(ts, &nsteps));
    PetscCall(TSGetTimeStep(ts, &dt));
    PetscCall(TSSetMaxSteps(ts, 1));
    PetscCall(TSSolve(ts, X));
    PetscCall(TSSetMaxSteps(ts, nsteps));
    PetscCall(TSSetStepNumber(ts, 0));
    PetscCall(TSSetTime(ts, 0));
    PetscCall(TSSetTimeStep(ts, dt));
    rectx->plotIdx  = 0;
    rectx->plotting = PETSC_FALSE;
    PetscCall(PetscLogStagePop());
    PetscCall(VecCopy(vec, X));
    PetscCall(VecDestroy(&vec));
    PetscCall(PetscObjectStateIncrease((PetscObject)ctx->J));
  }
  /* go */
  PetscCall(PetscLogStageRegister("Solve", &stage));
  ctx->stage = 0; // lets not use this stage
#if defined(PETSC_HAVE_THREADSAFETY)
  ctx->stage = 1; // not set with thread safety
#endif
  //PetscCall(TSSetSolution(ts,X));
  PetscCall(PetscLogStagePush(stage));
#if defined(PETSC_HAVE_THREADSAFETY)
  starttime = MPI_Wtime();
#endif
#if defined(PETSC_HAVE_CUDA_NVTX)
  nvtxRangePushA("ex2-TSSolve-warm");
#endif
  PetscCall(TSSolve(ts, X));
#if defined(PETSC_HAVE_CUDA_NVTX)
  nvtxRangePop();
#endif
  PetscCall(PetscLogStagePop());
#if defined(PETSC_HAVE_THREADSAFETY)
  endtime = MPI_Wtime();
  ctx->times[LANDAU_EX2_TSSOLVE] += (endtime - starttime);
#endif
  /* clean up */
  PetscCall(DMPlexLandauDestroyVelocitySpace(&pack));
  PetscCall(TSDestroy(&ts));
  PetscCall(VecDestroy(&X));
  PetscCall(PetscFree(rectx));
  PetscCall(PetscFinalize());
  return 0;
}

/*TEST

  testset:
    requires: p4est !complex double defined(PETSC_USE_DMLANDAU_2D)
    output_file: output/ex2_0.out
    args: -dm_landau_num_species_grid 1,1 -dm_landau_Ez 0 -petscspace_degree 3 -petscspace_poly_tensor 1 -dm_landau_type p4est -dm_landau_ion_masses 2 -dm_landau_ion_charges 1 -dm_landau_thermal_temps 5,5 -dm_landau_n 2,2 -dm_landau_n_0 5e19 -ts_monitor -snes_rtol 1.e-10 -snes_stol 1.e-14 -snes_monitor -snes_converged_reason -snes_max_it 10 -ts_type arkimex -ts_arkimex_type 1bee -ts_max_snes_failures -1 -ts_rtol 1e-3 -ts_dt 1.e-1 -ts_max_time 1 -ts_adapt_clip .5,1.25 -ts_max_steps 2 -ts_adapt_scale_solve_failed 0.75 -ts_adapt_time_step_increase_delay 5 -dm_landau_amr_levels_max 2,2 -ex2_impurity_source_type pulse -ex2_pulse_start_time 1e-1 -ex2_pulse_width_time 10 -ex2_pulse_rate 1e-2 -ex2_t_cold .05 -ex2_plot_dt 1e-1 -dm_refine 0 -dm_landau_gpu_assembly true -dm_landau_batch_size 2 -dm_landau_verbose 2
    test:
      suffix: cpu
      args: -dm_landau_device_type cpu -ksp_type bicg -pc_type jacobi
    test:
      suffix: kokkos
      requires: kokkos_kernels
      args: -dm_landau_device_type kokkos -dm_mat_type aijkokkos -dm_vec_type kokkos -ksp_type bicg -pc_type jacobi
    test:
      suffix: cuda
      requires: cuda
      args: -dm_landau_device_type cuda -dm_mat_type aijcusparse -dm_vec_type cuda -mat_cusparse_use_cpu_solve -ksp_type bicg -pc_type jacobi
    test:
      suffix: kokkos_batch
      requires: kokkos_kernels
      args: -dm_landau_device_type kokkos -dm_mat_type aijkokkos -dm_vec_type kokkos -ksp_type preonly -pc_type bjkokkos -pc_bjkokkos_ksp_type bicg -pc_bjkokkos_pc_type jacobi
    test:
      suffix: kokkos_batch_coo
      requires: kokkos_kernels
      args: -dm_landau_device_type kokkos -dm_mat_type aijkokkos -dm_vec_type kokkos -ksp_type preonly -pc_type bjkokkos -pc_bjkokkos_ksp_type bicg -pc_bjkokkos_pc_type jacobi -dm_landau_coo_assembly

TEST*/