I would like to consider the derivative term in the Navier Stokes equation in the Lid Driven Cavity example. I see that just by setting the time parameter to True in the Navier stokes equation imported from modulus.sym.eq.pdes.navier_stokes. I think I will also need to add in some BoundaryConstraints because of the addition of this term but I am not sure what that would be.
I tried out the following solver script based on my limited understanding of the package
import os
import warnings
from sympy import Symbol, Eq, Abs
import modulus.sym
from modulus.sym.hydra import to_absolute_path, instantiate_arch, ModulusConfig
from modulus.sym.solver import Solver
from modulus.sym.domain import Domain
from modulus.sym.geometry.primitives_2d import Rectangle
from modulus.sym.domain.constraint import (
PointwiseBoundaryConstraint,
PointwiseInteriorConstraint,
)
from modulus.sym.domain.validator import PointwiseValidator
from modulus.sym.domain.inferencer import PointwiseInferencer
from modulus.sym.key import Key
from modulus.sym.eq.pdes.navier_stokes import NavierStokes
from modulus.sym.utils.io import (
csv_to_dict,
ValidatorPlotter,
InferencerPlotter,
)
@modulus.sym.main(config_path="conf", config_name="config")
def run(cfg: ModulusConfig) -> None:
# make list of nodes to unroll graph on
ns = NavierStokes(nu=0.01, rho=1.0, dim=2, time=True)
flow_net = instantiate_arch(
input_keys=[Key("x"), Key("y"), Key("t")],
output_keys=[Key("u"), Key("v"), Key("p")],
cfg=cfg.arch.fully_connected,
)
nodes = ns.make_nodes() + [flow_net.make_node(name="flow_network")]
# add constraints to solver
# make geometry
height = 0.1
width = 0.1
x, y, t_symbol = Symbol("x"), Symbol("y"), Symbol("t")
rec = Rectangle((-width / 2, -height / 2), (width / 2, height / 2))
time_range = {t_symbol: (0, 2 * 2)}
# make ldc domain
ldc_domain = Domain()
# top wall
top_wall = PointwiseBoundaryConstraint(
nodes=nodes,
geometry=rec,
outvar={"u": 1.0, "v": 0},
batch_size=cfg.batch_size.TopWall,
lambda_weighting={"u": 1.0 - 20 * Abs(x), "v": 1.0}, # weight edges to be zero
criteria=Eq(y, height / 2),
parameterization={t_symbol: 0},
)
ldc_domain.add_constraint(top_wall, "top_wall")
# no slip
no_slip = PointwiseBoundaryConstraint(
nodes=nodes,
geometry=rec,
outvar={"u": 0, "v": 0},
batch_size=cfg.batch_size.NoSlip,
criteria=y < height / 2,
)
ldc_domain.add_constraint(no_slip, "no_slip")
# interior
interior = PointwiseInteriorConstraint(
nodes=nodes,
geometry=rec,
outvar={"continuity": 0, "momentum_x": 0, "momentum_y": 0},
batch_size=cfg.batch_size.Interior,
lambda_weighting={
"continuity": Symbol("sdf"),
"momentum_x": Symbol("sdf"),
"momentum_y": Symbol("sdf"),
},
)
ldc_domain.add_constraint(interior, "interior")
# add validator
file_path = "openfoam/cavity_uniformVel0.csv"
if os.path.exists(to_absolute_path(file_path)):
mapping = {"Points:0": "x", "Points:1": "y", "U:0": "u", "U:1": "v", "p": "p"}
openfoam_var = csv_to_dict(to_absolute_path(file_path), mapping)
openfoam_var["x"] += -width / 2 # center OpenFoam data
openfoam_var["y"] += -height / 2 # center OpenFoam data
openfoam_invar_numpy = {
key: value for key, value in openfoam_var.items() if key in ["x", "y"]
}
openfoam_outvar_numpy = {
key: value for key, value in openfoam_var.items() if key in ["u", "v"]
}
openfoam_validator = PointwiseValidator(
nodes=nodes,
invar=openfoam_invar_numpy,
true_outvar=openfoam_outvar_numpy,
batch_size=1024,
plotter=ValidatorPlotter(),
)
ldc_domain.add_validator(openfoam_validator)
# add inferencer data
grid_inference = PointwiseInferencer(
nodes=nodes,
invar=openfoam_invar_numpy,
output_names=["u", "v", "p"],
batch_size=1024,
plotter=InferencerPlotter(),
)
ldc_domain.add_inferencer(grid_inference, "inf_data")
else:
warnings.warn(
f"Directory {file_path} does not exist. Will skip adding validators. Please download the additional files from NGC https://catalog.ngc.nvidia.com/orgs/nvidia/teams/modulus/resources/modulus_sym_examples_supplemental_materials"
)
# make solver
slv = Solver(cfg, ldc_domain)
# start solver
slv.solve()
if __name__ == "__main__":
run()
But I am getting the following error related to Unrolling of Graph. In this forum I found another link about this error about a different system but I still didn’t understand what I have to do to fix it.
[16:41:12] - Disabling JIT because functorch does not work with it.
[16:41:12] - JitManager: {'_enabled': False, '_arch_mode': <JitArchMode.ONLY_ACTIVATION: 1>, '_use_nvfuser': True, '_autograd_nodes': False}
[16:41:12] - GraphManager: {'_func_arch': True, '_debug': False, '_func_arch_allow_partial_hessian': True}
[16:41:12] - AmpManager: {'_enabled': False, '_mode': <AmpMode.PER_ORDER_SCALER: 0>, '_dtype': torch.float16, '_default_max_scale': 1, '_autocast_activation': False, '_autocast_firstlayer': False, '_special_terms': [], '_custom_max_scales': {}}
####################################
could not unroll graph!
This is probably because you are asking to compute a value that is not an output of any node
####################################
invar: [x, y, normal_x, normal_y, area]
requested var: [u, v]
computable var: [x, y, normal_x, normal_y, area, continuity]
####################################
Nodes in graph:
node: Sympy Node: continuity
evaluate: SympyToTorch
inputs: []
derivatives: [u__x, v__y]
outputs: [continuity]
optimize: False
node: Sympy Node: momentum_x
evaluate: SympyToTorch
inputs: [u, v]
derivatives: [p__x, u__t, u__x, u__x__x, u__y, u__y__y]
outputs: [momentum_x]
optimize: False
node: Sympy Node: momentum_y
evaluate: SympyToTorch
inputs: [u, v]
derivatives: [p__y, v__t, v__x, v__x__x, v__y, v__y__y]
outputs: [momentum_y]
optimize: False
node: Arch Node: flow_network
evaluate: FullyConnectedArch
inputs: [x, y, t]
derivatives: []
outputs: [u, v, p]
optimize: True
####################################
Error executing job with overrides: []
Traceback (most recent call last):
File "/home/apaul/modulus-sym/examples/ldc/ldc_2d_time.py", line 143, in <module>
run()
File "/home/apaul/venv/lib/python3.10/site-packages/modulus/sym/hydra/utils.py", line 111, in func_decorated
_run_hydra(
File "/home/apaul/venv/lib/python3.10/site-packages/hydra/_internal/utils.py", line 394, in _run_hydra
_run_app(
File "/home/apaul/venv/lib/python3.10/site-packages/hydra/_internal/utils.py", line 457, in _run_app
run_and_report(
File "/home/apaul/venv/lib/python3.10/site-packages/hydra/_internal/utils.py", line 223, in run_and_report
raise ex
File "/home/apaul/venv/lib/python3.10/site-packages/hydra/_internal/utils.py", line 220, in run_and_report
return func()
File "/home/apaul/venv/lib/python3.10/site-packages/hydra/_internal/utils.py", line 458, in <lambda>
lambda: hydra.run(
File "/home/apaul/venv/lib/python3.10/site-packages/hydra/_internal/hydra.py", line 132, in run
_ = ret.return_value
File "/home/apaul/venv/lib/python3.10/site-packages/hydra/core/utils.py", line 260, in return_value
raise self._return_value
File "/home/apaul/venv/lib/python3.10/site-packages/hydra/core/utils.py", line 186, in run_job
ret.return_value = task_function(task_cfg)
File "/home/apaul/modulus-sym/examples/ldc/ldc_2d_time.py", line 76, in run
no_slip = PointwiseBoundaryConstraint(
File "/home/apaul/venv/lib/python3.10/site-packages/modulus/sym/domain/constraint/continuous.py", line 351, in __init__
super().__init__(
File "/home/apaul/venv/lib/python3.10/site-packages/modulus/sym/domain/constraint/constraint.py", line 71, in __init__
self.model = Graph(
File "/home/apaul/venv/lib/python3.10/site-packages/modulus/sym/graph.py", line 111, in __init__
raise RuntimeError("Failed Unrolling Graph")
RuntimeError: Failed Unrolling Graph
Any help resolving or explaining what needs to be done would be appreciated. Thanks!