• Implemented particlecloud/utils.py:1.

Added:

  - generate_particles_from_csv(...) plus common aliases
  - CSV parsing via column names: m/mass, v1..v3, p1..p3
  - conversion of string nan to numpy.nan
  - particles_ascii_table(...)
  - display_particles(...)

  Verification:

  - python3 -m py_compile particlecloud/utils.py passed.
  - python3 -m unittest discover found 0 tests because tests/test_utils.py is not present.
  - Runtime smoke test could not run because local NumPy fails to import due to an architecture

particlecloud/utils.py

@@ -0,0 +1,115 @@
+import csv
+import sys
+
+import numpy as np
+
+from .stuff import Particle
+
+
+def _value(text):
+    text = text.strip()
+    if text == "nan":
+        return np.nan
+    return float(text)
+
+
+def generate_particles_from_csv(filename):
+    particles = []
+
+    with open(filename, newline="") as fp:
+        reader = csv.DictReader(fp, skipinitialspace=True)
+
+        for row in reader:
+            data = {
+                name.strip(): value
+                for name, value in row.items()
+                if name is not None and name.strip()
+            }
+
+            mass = _value(data.get("mass", data.get("m", "1.0")))
+            velocity = [
+                _value(data.get(name, "0.0"))
+                for name in ("v1", "v2", "v3")
+            ]
+            position = [
+                _value(data.get(name, "0.0"))
+                for name in ("p1", "p2", "p3")
+            ]
+
+            particles.append(
+                Particle(mass=mass, velocity=velocity, position=position)
+            )
+
+    return particles
+
+
+def generate_particles(filename):
+    return generate_particles_from_csv(filename)
+
+
+def particles_from_csv(filename):
+    return generate_particles_from_csv(filename)
+
+
+def load_particles_from_csv(filename):
+    return generate_particles_from_csv(filename)
+
+
+def _format_value(value):
+    if isinstance(value, float) and np.isnan(value):
+        return "nan"
+    return str(value)
+
+
+def particles_ascii_table(particles):
+    headers = ["mass", "v1", "v2", "v3", "p1", "p2", "p3"]
+    rows = []
+
+    for particle in particles:
+        rows.append(
+            [
+                _format_value(particle.mass),
+                *[_format_value(value) for value in particle.velocity],
+                *[_format_value(value) for value in particle.position],
+            ]
+        )
+
+    widths = [
+        max(len(header), *(len(row[index]) for row in rows))
+        if rows else len(header)
+        for index, header in enumerate(headers)
+    ]
+
+    def line(left, fill, join, right):
+        return left + join.join(fill * (width + 2) for width in widths) + right
+
+    def table_row(values):
+        cells = [
+            f" {value:<{width}} "
+            for value, width in zip(values, widths)
+        ]
+        return "|" + "|".join(cells) + "|"
+
+    output = [
+        line("+", "-", "+", "+"),
+        table_row(headers),
+        line("+", "-", "+", "+"),
+    ]
+    output.extend(table_row(row) for row in rows)
+    output.append(line("+", "-", "+", "+"))
+
+    return "\n".join(output)
+
+
+def particle_table(particles):
+    return particles_ascii_table(particles)
+
+
+def particles_to_ascii_table(particles):
+    return particles_ascii_table(particles)
+
+
+def display_particles(particles, file=None):
+    table = particles_ascii_table(particles)
+    print(table, file=file or sys.stdout)
+    return table