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Python API Usage

All I/O functions are available directly from the top-level cfd_io package.

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from cfd_io import read_file, write_file, do_convert, get_info

Inspect a File

get_info returns a FileInfo object with grid dimensions, variable names, and other metadata — without loading the full data arrays.

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from cfd_io import get_info

info = get_info("sample_flow.h5")
print(info.format)     # "hdf5"
print(info.nx, info.ny, info.nz)
print(info.var_names)
print(info.precision)  # "float64"

Read a File

read_file returns a tuple of (grid, flow, attrs):

  • grid — dict[str, ndarray] with coordinate arrays ("x", "y", "z")
  • flow — dict[str, ndarray] with flow variables ("pres", "temp", ...)
  • attrs — dict with scalar metadata (variable names, timesteps, etc.)
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from cfd_io import read_file

grid, flow, attrs = read_file("sample_flow.h5")

# access coordinates
x = grid["x"]  # shape (nx, ny, nz)

# access flow variables
pressure = flow["pres"]
temperature = flow["temp"]

For split formats that store grid and flow separately:

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grid, flow, attrs = read_file("flow.s8", grid_file="grid.s8")

Write a File

write_file takes the same (grid, flow, attrs) structure:

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from cfd_io import read_file, write_file

# read from one format
grid, flow, attrs = read_file("sample_flow.h5")

# write to another
write_file("output.dat", grid, flow, attrs)

Convert Between Formats

do_convert combines read_file and write_file into a single call:

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from cfd_io import do_convert

# HDF5 to Tecplot
do_convert("sample_flow.h5", "output.dat")

# Plot3D to HDF5 with metadata
do_convert("sample_grid.x", "output.h5", attrs={"mach": 6.0})

For split formats, provide the grid files:

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do_convert(
    "flow.s8",
    "output.h5",
    input_grid="grid.s8",
)

Working with the Data

Once you have the grid and flow dicts, use them with NumPy or any other tool:

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import numpy as np
from cfd_io import read_file

grid, flow, attrs = read_file("sample_flow.h5")

# compute velocity magnitude
u = flow["uvel"]
v = flow["vvel"]
vmag = np.sqrt(u**2 + v**2)

# slice a wall-normal profile at i=25
pres_profile = flow["pres"][25, :, 0]
y_profile = grid["y"][25, :, 0]