Input reference

A PRISM run reads one INI file: mpirun -np N exe/adam_prism_cpu input.ini (or adam_prism_fnl). This page lists every section and key PRISM reads, with its type, whether it is required, its default, the accepted values and what happens on an invalid one. The sections the library reads for every application ([IO], [grid], [amr], [amr_marker_N], [runge_kutta], [weno], [fdv], [solids], [slices], the forest manifest) are in the library input reference, with PRISM's use of each; PRISM's additional rules for them are below. The library page also gives the parsing rules and the legend of the Req. column.

Read the hazards first: they collect the combinations PRISM refuses, and the ones it accepts but handles differently than the key names suggest.

Program entry and read order

adam_prism_cpu [file] / adam_prism_fnl [file] (default input.ini). A file with a [forest] section and realms_number >= 1 is a forest manifest; otherwise it is itself a single-realm input.

A realm input is read in this order: [IO] → [numerics] → [physics] → [runge_kutta] scheme and the coil counts (the memory budget) → the library sections ([grid], [amr], markers, [weno], [runge_kutta], [fdv], [solids], [slices]) → [bc_*] → [PIC] and [particle_injection] (PIC models) → [time] → [initial_conditions] → [coils_input] → [grms] → [magnetic_field_at_center_domain] → [probes] → [leapfrog] (PIC leapfrog) → [external_fields] → [fWLayer] → [PML]. The backend then checks the combinations (time and space schemes, PML, PIC current) and stops on the ones it does not implement.

CRLF. A Windows (CRLF) input reads as an LF one on both backends (see the library parsing rules).

Units. SI, except under the non-dimensional models (AdimEM, AdimPIC), where lengths are divided by L0, fields by B0 and D0 = B0 c0 ε0, times by T0 = L0/c0; the input stays in SI and PRISM converts it.

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[IO]

The library keys are in the library reference; PRISM uses save_memory_status, save_curl_fields, save_divergence_fields and the seam div(B) monitor seam_divB_tol / seam_divB_error, which FLUME does not. PRISM adds one key.

Key	Type	Req.	Default	Accepted / invalid	Meaning
save_fields	string	no	all	all, em; other values are fatal	all: every field in the field files. em: D and B only (production runs); the save_residual/curl/divergence_fields flags still add their arrays.

A cadence <= 0 disables that output, end of run included (#97).

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[numerics]

Every key is required; an unknown value is fatal.

Key	Accepted values	Meaning
scheme_time	runge_kutta, leapfrog, blanes_moan, commutator_free_magnus (also UPPER and Capitalised)	Time integration. Only runge_kutta runs: the other three are refused at initialization on both backends (#55).
scheme_space	fd_centered, fv_centered, weno (also UPPER and Capitalised)	Spatial scheme. weno runs on the CPU backend only (the FNL backend refuses it).
reconstruction_variables	conservative, characteristics	Variables the WENO path reconstructs.
constrained_transport	no, D, B, DB (case variants accepted)	Which GLM scalars to carry: φ for D, ψ for B. See the divergence-correction matrix.
divergence_correction	no, hyperbolic, poisson	hyperbolic: the GLM cleaning of the scalars selected by constrained_transport (required: D, B or DB). poisson: refused at load. no: no correction; a constrained_transport other than no is then ignored with a warning.

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[physics]

Key	Type	Req.	Default	Accepted / invalid	Meaning
physical_model	string	yes	—	EM (em, Electromagnetic, electromagnetic, Maxwell, maxwell), PIC (pic, ParticleInCell, particleincell), AdimEM (adimem, AdimensionalizedElectromagnetic, adimensionalelectromagnetic), AdimPIC (adimpic, adim_PIC, adim_pic); other values are fatal	Maxwell's equations, with particles (PIC), in SI or non-dimensional form. A PIC model adds the charge density rho to the state.
L0	real	cond. (AdimEM, AdimPIC)	—	> 0, otherwise fatal	Reference length (m).
B0	real	cond. (AdimEM, AdimPIC)	—	> 0, otherwise fatal	Reference magnetic field (T).
chi	real	cond. (divergence_correction = hyperbolic)	—	> 0, otherwise fatal	GLM propagation speed, in units of c: the fastest wave is max(1, chi) c0.
alpha	real	no	0	>= 0, otherwise fatal	GLM damping rate (1/s, or 1/T0 non-dimensional); > 0 also caps the time step at 1/alpha. Read only with hyperbolic.

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Library sections in PRISM

Section	PRISM rule
[grid]	ngc >= fdv_order/2 (fatal); with scheme_space = weno also ngc >= [weno] S (fatal). Extents are divided by L0 in a non-dimensional model.
[amr]	Refinement at initialization only, during the [initial_conditions] amr_iterations passes; frequency is read and unused, regrid_prolongation is unused.
[amr_marker_N]	Mode 1 primitive-box refines; mode 3 (AMR_TV) refines on the total variation of the coils' current density (tol, delta_type, delta_fine, delta_coarse). stl is fatal. Mode 1 solid, mode 2, mode 4 and mode 5 do nothing, silently.
[runge_kutta]	EM on CPU: every scheme, Yoshida included. EM on FNL: Yoshida is refused. PIC: runge-kutta-ssp-22/33/54 only. The PML, the charge-conserving PIC current and the staged path (2:1 faces, forests) need an SSP scheme (the PIC current one of SSP-22/33/54).
[weno]	Used only with scheme_space = weno (CPU). weights (js, si) is used; ROR is not implemented.
[fdv]	fdv_scheme (FD, FV) selects PRISM's operators and the coil stamping; fdv_order the order of the centred operators, which the t0 elliptic solves also use (they accept 2, 4, 6, 8).
[solids]	Loaded and passed to the Runge-Kutta stages; no committed PRISM input uses solids.

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[bc_x_min], [bc_x_max], [bc_y_min], [bc_y_max], [bc_z_min], [bc_z_max]

One key per section, required.

Key	Accepted values	Meaning
type	extrapolation, Neumann, Dirichlet, Silver_Muller, periodic, PEC (or pec); case-sensitive, other values are fatal. radiative is refused (#57).	Face boundary condition.

• periodic is the library's periodicity (BC_PERIODIC = -1): the tree builds periodic neighbours and the ghost exchange fills the periodic ghosts, across blocks and ranks. The two faces of an axis must be both periodic or neither (fatal).
• Dirichlet writes zero into the ghosts; there is no key for a prescribed value.
• Edge and corner ghost rows receive no boundary condition.
• Silver_Muller is spelled with an underscore.
• The elliptic map gives the boundary the t0 solves see.

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[time]

Every key is required.

Key	Type	Meaning
it_max	int	> 0: stop after it_max steps. <= 0: run to time_max.
time_max	real	End time (s; divided by T0 in a non-dimensional model).
CFL	real	CFL number on the fastest wave, max(1, chi) c0 (upper-case key). The PML (C_gamma) and the GLM damping (alpha) may cap the step further.

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[initial_conditions]

Key	Type	Req.	Accepted / invalid	Meaning
amr_iterations	int	yes	negative values are clamped to 0	Initial-condition + AMR passes: each sets the initial condition and runs the markers.
type	string	yes	see below; other values are fatal	Initial field.

type	Extra keys (all required, real unless stated)	Field
vacuum	—	Every variable zero.
plane_wave	kx, ky, kz (direction components), lambda (wavelength), B0 (amplitude, T)	A plane wave of wavelength lambda along (kx, ky, kz), D = B0 c0 ε0.
gaussian_pulse	B0, k0 (carrier wavenumber), r0 (centre along the direction), sigma (> 0, width), pulse_direction (string)	A Gaussian-enveloped wave packet.
gaussian_derivative_pulse	B0, r0, sigma (> 0), pulse_direction (string); optional k0 (carrier wavenumber, default 0)	A pulse with no zero-frequency content: single-cycle with k0 = 0, a packet around k0 otherwise.
rmf_field	[external_fields] RMF_frequency, RMF_B_amplitude, RMF_rotation_axis (X, Y, Z, either case; other values are fatal)	A rotating magnetic field.
uniform_field	B_x, B_y, B_z	A uniform magnetic field.
riemann-problem	—	Refused: its regions were read but never applied (#56).
magnetic_nozzle, rmf_magnetic_nozzle	—	Refused: use [external_fields] external_fields_applied for a nozzle field (also refused, see there).

pulse_direction accepts +x, -x, +y, -y, +z, -z; another value is fatal when the initial condition is set. Under the non-dimensional models the pulse lengths are given in SI and converted.

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[coils_input] and [coils_input_coil_N]

Coil current sources, stamped into the current density J as a Gaussian distribution around the coil path.

[coils_input]

Key	Type	Req.	Meaning
rectangular_coils_number	int	yes	Rectangular loops.
circular_coils_number	int	yes	Circular loops.
solenoid_coils_number	int	yes	Solenoids.
helicon_coils_number	int	yes	Helicon antennas (polylines).
time_delay	real	cond. (any coil)	Ramp-up time: the current is multiplied by g(s) = 10s³ − 15s⁴ + 6s⁵, s = t/time_delay clamped to [0, 1], so it grows smoothly from zero at t0 to full at time_delay. With time_delay <= 0 the coils carry full current at t0, and the t0 magnetic field is solved for (see [PIC] magnetic_field_elliptic_initialization).

The four counts are always required, even when they are all zero.

[coils_input_coil_N] (N = 1..total coils)

Key	Type	Req.	Accepted / invalid	Meaning
coil_type	string	yes	rectangular, circular, solenoid, helicon; another value is accepted silently and stamps no coil	Geometry.
current_type	string	yes	DC_current, AC_current; another value is accepted silently and reads no amplitude	Waveform.
sigma	real	yes	—	Width of the Gaussian current distribution.
x_center, y_center, z_center	real	yes (every kind)	—	Coil centre.
normal	string	yes (every kind)	+x, -x, +y, -y, +z, -z; another value stamps no coil, silently	Coil plane normal (the axis of a solenoid).
lx, ly	real	rectangular	—	Loop sides.
r_coil	real	circular, solenoid, helicon	—	Radius.
l_solenoid	real	solenoid	—	Length.
windings	int	solenoid	—	Turns.
N_points	int	helicon	<= 50, otherwise fatal	Points of the antenna path.
x_point_K, y_point_K, z_point_K	real	helicon, K = 1..N_points	—	Antenna path points.
Amplitude	real	yes (DC_current, AC_current)	—	Current amplitude (A).
Frequency, Phase	real	AC_current	—	Frequency (Hz) and initial phase (degrees).

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[external_fields]

Key	Type	Req.	Accepted / invalid	Meaning
external_fields_applied	string	yes	none (no), RMF, uniform_field (UniformField), and the case variants; magnetic_nozzle and rmf_and_magnetic_nozzle are parsed and refused at initialization (no backend implements them); other values are fatal	External field added to the evolved one.
RMF_frequency, RMF_B_amplitude	real	RMF	—	Rotating field frequency (Hz) and amplitude (T).
RMF_rotation_axis	string	RMF	X, Y, Z (either case); another value leaves the rotation indices undefined, silently	Rotation axis.
Uniform_field_D_amplitude (or Uniform_D_amplitude)	real	uniform_field	—	Uniform D amplitude.
Uniform_field_B_amplitude (or Uniform_B_amplitude)	real	uniform_field	—	Uniform B amplitude.
Uniform_field_direction (or Uniform_direction)	string	uniform_field	x, y, z (either case); other values are fatal	Direction of the uniform field.

For each pair, the first name is read first and the second is the fallback.

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[fWLayer]

A far-wave damping layer along chosen domain faces.

Key	Type	Req.	Accepted / invalid	Meaning
width	real	yes (even when no layer is used)	>= 0, otherwise fatal	Physical layer width; the cells per face are min(ni, ceiling(width/ds)). 0 disables the layer.
x_minus_layer, x_plus_layer, y_minus_layer, y_plus_layer, z_minus_layer, z_plus_layer	string	yes	yes, no (case variants); other values are fatal	Faces carrying the layer.

The removed key C (cells per face) is rejected by the removed-keys lint.

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[PML]

A perfectly matched layer, stored on the boundary blocks only. The section is optional: without PML_type the PML is off.

Key	Type	Req.	Default	Accepted / invalid	Meaning
PML_type	string	no	none	no/none, CLASSIC (PML, STANDARD), CLASSIC_DIRECT (DIRECT, CLASSIC-DIRECT), CFS (CPML, CFS_PML), BERMUDEZ, with case variants; other values are fatal	PML formulation.
width	real	yes (PML on)	0	> 0, otherwise fatal	Physical layer width.
C_gamma (or c_gamma)	real	no	0.1	> 0, otherwise fatal	Time-step cap dt <= C_gamma / gamma_max.
x_minus_layer … z_plus_layer	logical	yes (PML on)	—	at least one .true., otherwise fatal	Faces carrying the PML.
gamma_max	real	CLASSIC, CLASSIC_DIRECT, CFS	—	>= 0, otherwise fatal	Maximum damping.
gamma_exponent	real	CLASSIC, CLASSIC_DIRECT, BERMUDEZ	—	> 0, otherwise fatal	Exponent of the damping profile.
alfa_max	real	CFS	—	>= 0, otherwise fatal	CFS frequency shift (spelled alfa).
k_max	real	CFS	1	> 0, otherwise fatal	CFS stretching.
beta	real	BERMUDEZ	—	>= 0, otherwise fatal	Bermúdez profile coefficient.

See the PML hazards.

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[PIC] (PIC models only)

Key	Type	Req.	Default	Accepted / invalid	Meaning
problem_type	string	yes	—	plasma, single_particle; another value is accepted silently and injects no particle	Problem kind.
plasma_domain	string	plasma	—	uniform (all, full, uniform_domain), cilinder (uniform_cilinder), slab (uniform_slab), box (uniform_box), with case variants; other values are fatal	Region the plasma fills. Note the spelling cilinder.
cilinder_radius, cilinder_length, cilinder_x_center, cilinder_y_center, cilinder_z_center	real	cilinder	—	—	Cylinder.
cilinder_axis	char	cilinder	—	x, y, z; another value leaves the particle positions undefined, silently	Cylinder axis.
slab_normal	string	slab	—	x, y, z (either case); other values are fatal	Slab normal.
slab_thickness, slab_center	real	slab	—	thickness > 0, otherwise fatal	Slab along its normal.
box_length_x, box_length_y, box_length_z, box_x_center, box_y_center, box_z_center	real	box	—	—	Box.
plasma_density	real	plasma	—	—	Total density (ions + electrons + neutrals) per unit volume: the particle count is nint(plasma_density × volume / particle_weight) of the plasma region.
particle_weight	real	no	1	> 0, otherwise fatal	Real particles per macroparticle: each particle carries particle_weight times the charge and the mass of its species (q/m unchanged).
neutral_fraction	real	plasma	—	—	Fraction of neutrals; the rest is split evenly into ions and electrons.
initialization	string	no	coherent	coherent only; other values are fatal	Field initialization.
electric_field_elliptic_initialization	logical	no	.true.	logical	Solve D(G) φ = −ρ/ε at t0 and correct D, so div D = ρ to round-off.
magnetic_field_elliptic_initialization	logical	no	.true.	logical	Solve D(G) A = −μ J at t0 and add curl A to B, when J ≠ 0 at t0.
elliptic_initialization_closure	string	no	grounded	grounded, isolated; other values are fatal. isolated is fatal unless both t0 solves are on, and at t0 unless exactly one axis is non-periodic with PEC faces (the others periodic or null)	Mean fields of the t0 solves: grounded zero (the PEC walls at one potential, no trapped flux), isolated those of the same sources in open space along the non-periodic axis (numerics).
elliptic_correction	logical	—	—	.true. is fatal (#84 E3d); the lint rejects the key	Removed.
particle_weighting_model	string	yes	—	NGP, CIC, TSC, cubic (3rd), quartic (4th), quintic (5th), sextic (6th), gaussian, with case variants; other values are fatal	Charge deposition.
current_weighting_model	string	yes	—	the same list, plus conserving (charge_conserving); other values are fatal	Current deposition. conserving needs fd_centered, runge_kutta and SSP-22/33/54 (fatal otherwise).
field_weighting_model	string	yes	—	0D … 6D, gaussian, londrillo, totorica (esirkepov_Q2), esirkepov_Q5, esirkepov_Q6, esirkepov_Q8, esirkepov_Q10, with case variants; other values are fatal	Field gather to the particles.
current_conserving_solver	string	no	londrillo	londrillo, totorica (esirkepov_Q2), esirkepov_Q5/Q6/Q8/Q10; the old names esirkepov, direct/line, esirkepov-modified stop with the new name; other values are fatal. Ignored unless current_weighting_model = conserving.	Matched current of the conserving deposit. With periodic faces londrillo stops at the first step (CPU).
esirkepov_tail_cleanup	logical	no	.false.	logical	Tail cleanup of the Esirkepov current; stops at the first step with periodic faces (CPU).
filter_deposition	logical	no	.false.	logical	Filter the deposited source.
sigma, cutoff_sigma	real	cond. (any Gaussian model)	—	> 0, otherwise fatal	Gaussian width and cut-off (in widths).
gaussian_support_cells	int	no	automatic	—	Gaussian support in cells; automatic from the final cell size when absent.
scheme_time	string	yes	—	runge_kutta, leapfrog (case variants); another value warns and falls back to runge_kutta	Particle push. leapfrog is refused at initialization.

The particle closure at the domain faces is not an input key: it follows the field [bc_*] type (periodic faces wrap the particles, every other kind keeps the legacy closure, where a particle leaving the domain stops the run).

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[particle_injection] (PIC models only)

For problem_type = plasma:

Key	Type	Req.	Default	Accepted / invalid	Meaning
random_seed	int	no	processor-dependent	any	Fixed seed, for a reproducible plasma.
space_random_number_generator	string	yes	—	random, layered (case variants); other values are fatal	Position sampling.
space_pairing	string	yes	—	yes, no; other values are fatal	Electrons placed on the ions' positions.
ions_velocity_distribution, electrons_velocity_distribution, neutrals_velocity_distribution	string	yes	—	uniform_maxwellian (maxwellian, uniform), non_uniform_maxwellian, drift (pure_drift), with case variants; other values are fatal	Velocity distribution per species.
ionic_temperature, electronic_temperature, neutrals_temperature	real	cond. (that species uniform_maxwellian)	—	—	Temperature (K).
ionic_temperature_x/_y/_z, electronic_temperature_x/_y/_z, neutrals_temperature_x/_y/_z	real	cond. (that species non_uniform_maxwellian)	—	—	Temperature per axis (K).
velocity_random_number_generator	string	cond. (any Maxwellian species)	—	random, layered; other values are fatal	Velocity sampling.
velocity_pairing	string	cond. (any Maxwellian species)	—	yes, no; other values are fatal. yes needs the same distribution, temperatures and drifts for ions and electrons (fatal otherwise).	Electrons take the ions' velocities.
ions_drift_x/_y/_z, electrons_drift_x/_y/_z, neutrals_drift_x/_y/_z	real	yes	—	—	Drift velocity per species (m/s).
v_av_correction	string	yes	—	yes, no; other values are fatal	Remove the sampled mean velocity.

For problem_type = single_particle: x_position, y_position, z_position, charge, mass, v_drift_x, v_drift_y, v_drift_z, all real and required.

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[leapfrog] (PIC leapfrog only)

is_filtered (logical), nu, alpha (real), all required, read only with [PIC] scheme_time = leapfrog, which is then refused at initialization: the section has no working use.

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Diagnostics

[grms]

Key	Type	Req.	Default	Accepted / invalid	Meaning
save_history	logical	no	.false.	logical	Write the RMS-field history.
history_save	int	no	10	—	Its cadence in steps.
region_type	string	no	all	all, cylinder; other values are fatal	Region of the RMS.
center_x, center_y, center_z, axis_x, axis_y, axis_z, radius, length	real	cylinder	—	axis non-zero, radius and length > 0, otherwise fatal	Cylinder (the axis is normalised).

[magnetic_field_at_center_domain]

Key	Type	Req.	Default	Meaning
save_history	logical	no	.false.	Write the history of B at the domain centre.
history_save	int	no	10	Its cadence in steps.

[probes]

Optional: without a [probes] section, or with neither point_N nor plane_N keys, there are no probes. Each probe samples the whole state at a point by trilinear interpolation.

[probes]
save_every = 4
point_1 = -0.04 0.0 0.0       ; one probe at x y z
plane_1 = x 0.4364 48 48      ; a plane of probes normal to x at x = 0.4364: 48 x 48 points over y and z

Key	Type	Req.	Accepted / invalid	Meaning
save_every	int	yes (probes on)	> 0, otherwise fatal	Cadence in steps; the last step is always saved.
point_N	3 reals	no	inside the domain, otherwise fatal	A probe at x y z.
plane_N	axis, real, 2 ints	no	axis x/y/z, abscissa inside the domain, n1 n2 >= 1, otherwise fatal	A plane of n1 x n2 probes normal to the axis at the abscissa, on the cell centres of a uniform lattice spanning the domain along the other two axes (normal x: y then z; y: x then z; z: x then y). With n equal to the cells of the grid along an axis the probes sit on the cell centres.

Coordinates are in the grid's units (divided by L0 non-dimensional). point_N and plane_N are numbered from 1 without gaps: the first missing number ends the list. The former input, probes_number and one [probe_N] section (x, y, z) per probe, is refused at initialization: write each former probe as a point_N, or a full lattice of them as one plane_N.

Output (rank 0): <output_basename>-probe_NN.dat per point (one row per save: it time and the variables) and <output_basename>-plane_NN.dat per plane (per save, n1 x n2 rows it time i j and the variables, i fastest). The rows are not flushed at every save (a flush per file is a file-system round trip; on a shared file system it stalled every rank for seconds): they reach the files when the runtime buffers fill and at the end of the run, so after a crash the last rows may be missing.

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Hazards

Divergence correction

The GLM scalars φ (for D) and ψ (for B) exist only under hyperbolic, and their slots follow physics (#11, #61):

constrained_transport	divergence_correction	Result
no	no	nv = 9
D, B, DB	no	constrained transport ignored with a warning, nv = 9
D or B	hyperbolic	nv = 10 (φ or ψ in slot 7)
DB	hyperbolic	nv = 11 (φ in 7, ψ in 8)
no	hyperbolic	refused at initialization
any	poisson	refused at initialization

PIC adds rho, one more slot. At a 2:1 AMR seam div(B) is not kept at round-off: the seam injects an O(h^p) source that converges under refinement but grows in time at fixed h (#29); [IO] seam_divB_tol makes the growth visible.

PML

• CPU: CLASSIC, CLASSIC_DIRECT, BERMUDEZ, CFS, on fd_centered, with no divergence correction and no constrained transport, with an SSP Runge-Kutta scheme; anything else is fatal.
• FNL: fd_centered, runge_kutta with an SSP scheme, no hyperbolic correction, no constrained transport; anything else is fatal.
• CLASSIC_DIRECT is not a Runge-Kutta PML: it skips the auxiliary-variable integration and applies direct per-face damping. It is a testing instrument, not the production path.
• Enabling the section with every face flag .false. is fatal; each PML_type has its own required parameters, and a missing one is fatal, not defaulted.

Elliptic boundary map

The t0 solves ([PIC] electric_field_elliptic_initialization, magnetic_field_elliptic_initialization) run on FLAIL's FFT solver with PRISM's own operator D(G) of order fdv_order. Each face kind maps to an elliptic kind, then to a FLAIL face kind:

[bc_*] type	Elliptic kind	FLAIL face kind
periodic	periodic	FLAIL_BC_PERIODIC
Dirichlet	Dirichlet	FLAIL_BC_ZERO_GHOSTS (every ghost layer zero)
PEC	PEC	FLAIL_BC_DIRICHLET (φ, tangential A), FLAIL_BC_NEUMANN (normal A)
Neumann, Silver_Muller	exact/open	FLAIL_BC_FREE_GHOSTS (the free-space potential of the source in the ghosts, summed over the whole domain)
extrapolation	—	fatal, at the first t0 solve

The map is total and stops on what it cannot map, but only when a solve first touches the face: an input with an extrapolation face passes initialization and stops at t0 if a PIC field or a t0 current needs a solve. A null axis takes the periodic kind.

Refused combinations

Input	Where it stops
[numerics] scheme_time = leapfrog, blanes_moan, commutator_free_magnus	initialization, both backends (#55)
[PIC] scheme_time = leapfrog	initialization, both backends
[numerics] divergence_correction = poisson	load
hyperbolic without constrained transport	load
[bc_*] type = radiative	load (#57)
[initial_conditions] type = riemann-problem, magnetic_nozzle, rmf_magnetic_nozzle	load (#56)
[external_fields] external_fields_applied = magnetic_nozzle, rmf_and_magnetic_nozzle	initialization
[numerics] scheme_space = weno on FNL	initialization
runge-kutta-yoshida on FNL; a non-SSP scheme with PIC, the PML or the staged path	initialization
[PIC] current_weighting_model = conserving on the CPU backend with more than one block or one rank	the first step (the CPU charge-conserving deposit is single-block, single-rank)
A refined grid that enters a t0 elliptic solve	the solve (#84 E7: the wide operator across 2:1 faces is not defined)
fdv_order = 10 with a t0 elliptic solve	the solve (FLAIL accepts 2, 4, 6, 8)