pdeapp Reference

pdeapp.txt is the Text2Code application configuration file. It is a flat list of assignments read by text2code/text2code/readpdeapp.cpp. The same conceptual fields also appear in MATLAB/Python/Julia pde structures, but not every frontend field is parsed from pdeapp.txt.

For model equations, see pdemodel reference and Physics Models.

Syntax

key = value;
key = [1, 2, 3];
key = ["expr1", "expr2"];

Supported forms:

• Strings use double quotes.
• Numeric lists use square brackets.
• repeat(value, count) is supported inside numeric lists.
• physicsparamcases supports bracketed rows or semicolon-separated rows.
• Statements end with ;.

Integer versus floating-point parsing

The parser stores a scalar as floating-point only when the text contains . or e. Use time = 0.0;, not time = 0;, when setting a floating field.

Required pdeapp.txt Keys

The Text2Code parser errors if any of these keys are missing:

Key	Type	Purpose
model	string	Model formulation: ModelC, ModelD, or ModelW.
modelfile	string	Path to pdemodel.txt.
meshfile	string	Path to binary mesh input.
discretization	string	ldg or hdg.
platform	string	cpu or gpu.
mpiprocs	int	Number of MPI ranks intended for generated data.
porder	int	Polynomial order.
pgauss	int	Quadrature order/degree used by preprocessing.
physicsparam	list(float)	Physics parameter vector mu.
tau	list(float)	Stabilization parameter vector.
boundaryconditions	list(int)	Boundary-condition code per boundary expression.
boundaryexpressions	list(string)	Geometric predicates defining boundary IDs.

Problem Definition

Key	Type	Default	Required	Accepted values / notes
model	string	ModelD	Yes	ModelC, ModelD, ModelW.
modelfile	string	pdemodel.txt	Yes	File path relative to datapath or working directory.
meshfile	string	mesh.bin	Yes	Binary mesh file read by preprocessing.
discretization	string	ldg	Yes	ldg, LDG, hdg, HDG; sets hybrid.
platform	string	cpu	Yes	cpu or gpu; actual backend also depends on linked executable.
modelnumber	int	0	No	Positive values suffix datain/dataout directories.
builtinmodelID	int	unset	No	Built-in provider dispatch ID where supported.
runmode	int	0	No	Runtime mode selector used by solver paths.
debugmode	int	0	No	1 prints parsed parameters.
linearproblem	int	0	No	Marks linear problem paths where supported.
subproblem	int	0	No	Subproblem selector used by coupled workflows.

Paths and Generated Data

Key	Type	Default	Required	Notes
exasimpath	string	auto	No	Source/install root used by Text2Code for runtime data discovery.
datapath	string	path of pdeapp.txt or cwd	No	Base directory for datain/ and dataout/.
xdgfile	string	empty	No	Optional coordinates/DG nodes input file.
udgfile	string	empty	No	Optional initial udg input file.
vdgfile	string	empty	No	Optional external/other-DG field input file.
wdgfile	string	empty	No	Optional auxiliary w field input file.
uhatfile	string	empty	No	Optional HDG trace input file.
partitionfile	string	empty	No	Optional partition input.
gendatain	int	1	No	Write backend binary input bundle.
gencode	int	1	No	Generate C++ model code.
writemeshsol	int	1	No	Write mesh and solution binary data.

Mesh and Dimensions

Key	Type	Default	Required	Notes
ncu	int	1	No	Number of primary solution components.
ncv	int	0	No	Number of external/other-DG components in text parser naming.
ncw	int	0	No	Number of auxiliary w components.
nsca	int	0	No	Number of scalar visualization fields.
nvec	int	0	No	Number of vector visualization fields.
nten	int	0	No	Number of tensor visualization fields.
nsurf	int	0	No	Surface output count.
nvqoi	int	0	No	Volume QoI count.
neb	int	4096	No	Element block size for batched kernels.
nfb	int	8192	No	Face block size for batched kernels.
nodetype	int	1	No	Node distribution selector.

Some dimensions such as nd, nc, ncq, ncx, and element counts are derived from mesh/model preprocessing rather than typically written by hand in pdeapp.txt.

Discretization and Time Integration

Key	Type	Default	Required	Notes
porder	int	1	Yes	Polynomial order.
pgauss	int	2	Yes	Quadrature order/degree.
temporalscheme	int	0	No	Temporal scheme selector.
torder	int	1	No	Time-integration order.
nstage	int	1	No	Number of stages.
time	float	0.0	No	Initial time; write with decimal.
dt	list(float)	empty	No	Time-step sequence; first positive value sets tdep=1.
tdep	int	0	No	Time-dependent flag; also inferred from dt.
wave	int	0	No	Wave-model flag used by ModelW-style paths.

Solver Configuration

Key	Type	Default	Required	Notes
nonlinearsolver	int	0	No	Nonlinear solver selector.
NewtonIter	int	20	No	Maximum Newton iterations.
NewtonTol	float	1e-6	No	Newton convergence tolerance.
NLparam	float	0.0	No	Nonlinear solver parameter.
NLMatrixType	int	0	No	Nonlinear matrix selector.
linearsolver	int	0	No	Linear solver selector.
GMRESiter	int	200	No	Maximum GMRES iterations.
GMRESrestart	int	25	No	GMRES restart length in Text2Code defaults.
GMRESortho	int	0	No	Orthogonalization selector.
GMREStol	float	1e-3	No	Linear solver tolerance.
preconditioner	int	0	No	Preconditioner selector in Text2Code defaults.
precMatrixType	int	0	No	Preconditioner matrix type selector.
ppdegree	int	0	No	Polynomial-preconditioner degree.
RBdim	int	5	No	Reduced-basis preconditioner dimension.
matvecorder	int	1	No	Matrix-vector approximation order.
matvectol	float	1e-3	No	Matrix-vector finite-difference tolerance.

Frontend defaults can differ from Text2Code defaults. For example, MATLAB and Python currently initialize GMRESrestart = 100, preconditioner = 1, and RBdim = 0.

Physics Parameters and Sweeps

Key	Type	Default	Required	Notes
physicsparam	list(float)	empty	Yes	Runtime physics parameter vector mu.
physicsparamcases	matrix(float)	empty	No	Standalone Text2Code sweep cases; each row has length numel(physicsparam).
physicsparamwarmstart	int	0	No	1 reuses previous case solution during standalone sweeps.
externalparam	list(float)	empty	No	Extra model parameters serialized separately from physicsparam.
tau	list(float)	empty	Yes	Stabilization parameters.
uinf	frontend field	frontend default	No	Frontend free-stream/reference values; not a Text2Code required key.

Example:

physicsparam = [1.4, 0.72, 1000.0, 0.3];
physicsparamcases = [
  [1.4, 0.72, 500.0, 0.3],
  [1.4, 0.72, 1000.0, 0.3],
  [1.4, 0.72, 1500.0, 0.3]
];
physicsparamwarmstart = 1;

See Parameter sweeps for output layout and frontend syntax.

Boundary and Interface Configuration

Key	Type	Default	Required	Notes
boundaryconditions	list(int)	empty	Yes	Boundary condition code for each boundary expression.
boundaryexpressions	list(string)	empty	Yes	Geometry predicates evaluated on mesh faces.
curvedboundaries	list(int)	empty	No	Curved-boundary flags.
curvedboundaryexprs	list(string)	empty	No	Expressions for curved-boundary projection.
periodicboundaries1	list(int)	empty	No	First periodic boundary ID set.
periodicexprs1	list(string)	empty	No	Matching coordinate expressions for first periodic set.
periodicboundaries2	list(int)	empty	No	Second periodic boundary ID set.
periodicexprs2	list(string)	empty	No	Matching coordinate expressions for second periodic set.
interfaceconditions	list(int)	empty	No	Coupled-interface condition codes.
interfacefluxmap	list(int)	empty	No	Interface flux component map.
cartgridpart	list(int)	empty	No	Cartesian grid partition specification.
extFhat	int	0	No	Enable external interface flux hook.
extUhat	int	0	No	Enable external interface trace hook.
extStab	int	0	No	Enable external stabilization hook.

See Boundary conditions for model-function interfaces.

Stabilization, Closure, and AV

Key	Type	Default	Required	Notes
convStabMethod	int	0	No	Convective stabilization selector.
diffStabMethod	int	0	No	Diffusive stabilization selector.
viscosityModel	int	0	No	Viscosity-model selector.
SGSmodel	int	0	No	Sub-grid-scale model selector.
rotatingFrame	int	0	No	Rotating-frame flag.
ALE	int	0	No	Arbitrary Lagrangian-Eulerian flag.
AV	int	0	No	Artificial-viscosity flag.
AVdistfunction	int	0	No	AV distance-function flag.
AVsmoothingIter	int	2	No	Number of AV smoothing iterations.
frozenAVflag	int	1	No	Freeze AV field where supported.
avparam1	list(float)	empty	No	Artificial-viscosity parameter vector.
avparam2	list(float)	empty	No	Additional artificial-viscosity parameter vector.

Synthetic Turbulence and DAE

Key	Type	Default	Required	Notes
stgNmode	int	0	No	Synthetic turbulence mode count.
stgib	list(float)	empty	No	Synthetic turbulence boundary data.
stgdata	list(float)	empty	No	Synthetic turbulence mode data.
stgparam	list(float)	empty	No	Synthetic turbulence parameters.
dae_steps	int	0	No	Number of DAE substeps.
dae_dt	list(float)	empty	No	DAE pseudo-time steps.
dae_alpha	float	1.0	No	DAE coefficient.
dae_beta	float	0.0	No	DAE coefficient.
dae_gamma	float	0.0	No	DAE coefficient.
dae_epsilon	float	0.0	No	DAE coefficient.

Output and Postprocessing

Key	Type	Default	Required	Notes
saveParaview	int	0	No	Enables VTK/ParaView output when visualization fields exist.
saveSolFreq	int	1	No	Saved solution frequency.
saveSolOpt	int	1	No	Saved solution option; implementation distinguishes compact/full solution storage.
timestepOffset	int	0	No	Offset used in time-dependent/restart output naming.
saveSolBouFreq	int	0	No	Boundary solution save frequency.
ibs	int	0	No	Boundary ID for boundary-solution output.
saveResNorm	int	0	No	Save residual norm history.
compudgavg	int	0	No	Compute averaged solution field where supported.

Frontend-only execution field:

Field	Type	Default	Scope	Notes
executionmode	int	0	Frontend-only	0 runs solve mode; 1 launches standalone postprocess mode. Not parsed from pdeapp.txt.

See Postprocessing.

Minimal pdeapp.txt

model = "ModelD";
modelfile = "pdemodel.txt";
meshfile = "mesh.bin";
discretization = "hdg";
platform = "cpu";
mpiprocs = 1;
porder = 2;
pgauss = 4;
physicsparam = [1.0];
tau = [1.0];
boundaryconditions = [1, 2, 3, 4];
boundaryexpressions = ["x < 1e-8", "x > 1-1e-8", "y < 1e-8", "y > 1-1e-8"];

Complete-Style Example Fragment

model = "ModelD";
modelfile = "pdemodel.txt";
meshfile = "mesh.bin";
discretization = "hdg";
platform = "cpu";
mpiprocs = 4;
porder = 3;
pgauss = 6;
physicsparam = [1.4, 0.72, 5000.0, 0.3];
tau = [1.0];
dt = [repeat(0.001, 100)];
saveSolFreq = 10;
saveParaview = 1;
nsca = 2;
nvec = 1;
boundaryconditions = [1, 2, 3, 4];
boundaryexpressions = ["x < -10", "x > 20", "wall_distance < 1e-8", "farfield > 0"];