Make a hex grid.

This uses a grid factory method to build an infinite 2-D grid of hexagons with pitch equal to 1.0 cm.

Learn more about grids.

import math

import matplotlib.patches as mpatches
import matplotlib.pyplot as plt
from matplotlib.collections import PatchCollection

from armi import configure
from armi.reactor import grids

configure(permissive=True)

hexes = grids.HexGrid.fromPitch(1.0)

polys = []
fig, ax = plt.subplots()
ax.set_aspect("equal")
ax.set_axis_off()

for hex_i in hexes.generateSortedHexLocationList(127):
    x, y, z = hex_i.getGlobalCoordinates()
    ax.text(x, y, f"{hex_i.i},{hex_i.j}", ha="center", va="center", fontsize=8)
    polys.append(mpatches.RegularPolygon((x, y), numVertices=6, radius=1 / math.sqrt(3), orientation=math.pi / 2))
patches = PatchCollection(polys, fc="white", ec="k")
ax.add_collection(patches)

# create a bounding box around patches with a small margin (2%)
bbox = patches.get_datalim(ax.transData)
bbox = bbox.expanded(1.02, 1.02)
ax.set_xlim(bbox.xmin, bbox.xmax)
ax.set_ylim(bbox.ymin, bbox.ymax)
ax.set_title("(i, j) indices for a hex grid")
plt.show()