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query_cell()

Query cell data for a single cell.

For temporal datasets, automatically sweeps all time points unless time_value is specified. For static datasets, returns values directly.

Parameters
  • cell_id (int) — The cell ID to query.
  • block_name (str | None, default: None) — Block name for MultiBlock meshes. Must be None for single-block meshes.
  • time_value (float | None, default: None) — Query a specific time value instead of sweeping all time points. Ignored for static datasets.
Returns

Returns a dictionary with array names as keys. Both static and temporal datasets use the same structure, with static datasets using time: [0].

# Scalars:
{
    "scalar_name": {
        "time": [0.0, 0.001, 0.002, ...],  # [0] for static
        "value": [val0, val1, val2, ...]
    },
    ...
}

# Vectors (3-component):
{
    "vector_name": {
        "time": [0.0, 0.001, 0.002, ...],  # [0] for static
        "x_value": [x0, x1, x2, ...],
        "y_value": [y0, y1, y2, ...],
        "z_value": [z0, z1, z2, ...]
    },
    ...
}

Examples​

Sweep all time steps​

from pyemsi import Plotter, examples
from matplotlib import pyplot

file_path = examples.transient_path()
plt = Plotter(file_path)
data = plt.query_cell(cell_id=0, block_name="1")

fig, ax = pyplot.subplots()
ax.plot(data["B-Mag (T)"]["time"], data["B-Mag (T)"]["value"], marker="o")
ax.set_xlabel("Time (s)")
ax.set_ylabel("B-Mag (T)")
ax.set_title("B-Mag (T) at Cell ID 0 in Block 1")
fig.tight_layout()
fig.savefig("docs/static/demos/query_cell.png")

Query Cell

Query a single time value​

from pyemsi import Plotter, examples

file_path = examples.transient_path()
plt = Plotter(file_path)

# Use time_point_value() to look up the time value for a given index
t = plt.time_point_value(4)   # 0.05  (5th time step, zero-based)

# Query only at that time value instead of sweeping all time steps
data = plt.query_cell(cell_id=0, block_name="1", time_value=t)

print(data["B-Mag (T)"]["time"])   # [0.05]
print(data["B-Mag (T)"]["value"])  # [0.10771600157022476]

See Also​