Improve speed in some modules by oscargus · Pull Request #22678 · matplotlib/matplotlib · GitHub
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Improve speed in some modules #22678

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Improve speed in some modules #22678

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10 changes: 6 additions & 4 deletions lib/matplotlib/cbook/__init__.py
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6 changes: 3 additions & 3 deletions lib/matplotlib/markers.py
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Original file line number Diff line number Diff line change
Expand Up @@ -677,7 +677,7 @@ def _set_pentagon(self):
self._path = polypath
else:
verts = polypath.vertices
y = (1 + np.sqrt(5)) / 4.
y = (1 + 5 ** (1 / 2)) / 4.

@timhoffm timhoffm Apr 25, 2022

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I'm not convinced of all these sqrt micro-optimizations. IMHO it makes the code less readable, and the performance gain is minimal. For example here

The sqrt is less than 2% of the the time of the immediate surrounding code in the function:

In [21]: %%timeit
    ...: Affine2D().scale(0.5)
    ...: polypath = Path.unit_regular_polygon(5)
    ...: verts = polypath.vertices
    ...: top = Path(verts[[0, 1, 4, 0]])
    ...: bottom = Path(verts[[1, 2, 3, 4, 1]])
    ...: left = Path([verts[0], verts[1], verts[2], [0, -y], verts[0]])
    ...: right = Path([verts[0], verts[4], verts[3], [0, -y], verts[0]])
    ...: 
61.1 µs ± 228 ns per loop (mean ± std. dev. of 7 runs, 10,000 loops each)

In [22]: %timeit np.sqrt(5)
2.36 µs ± 35 ns per loop (mean ± std. dev. of 7 runs, 100,000 loops each)

and that function _set_pentagon() again is only used to create a new marker object, which in itself is quite rare. So I bet the performance gain is not measurable in any real example.

top = Path(verts[[0, 1, 4, 0]])
bottom = Path(verts[[1, 2, 3, 4, 1]])
left = Path([verts[0], verts[1], verts[2], [0, -y], verts[0]])
Expand Down Expand Up @@ -747,7 +747,7 @@ def _set_hexagon2(self):
else:
verts = polypath.vertices
# not drawing inside lines
x, y = np.sqrt(3) / 4, 3 / 4.
x, y = 3 ** (1 / 2) / 4, 3 / 4.
top = Path(verts[[1, 0, 5, 4, 1]])
bottom = Path(verts[1:5])
left = Path(np.concatenate([
Expand All @@ -772,7 +772,7 @@ def _set_octagon(self):
self._transform.rotate_deg(22.5)
self._path = polypath
else:
x = np.sqrt(2.) / 4.
x = 2 ** (1 / 2) / 4.
self._path = self._alt_path = Path(
[[0, -1], [0, 1], [-x, 1], [-1, x],
[-1, -x], [-x, -1], [0, -1]])
Expand Down
94 changes: 49 additions & 45 deletions lib/matplotlib/path.py
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Original file line number Diff line number Diff line change
Expand Up @@ -822,45 +822,48 @@ def circle(cls, center=(0., 0.), radius=1., readonly=False):
Bezier Cubic Splines <https://www.tinaja.com/glib/ellipse4.pdf>`_.
"""
MAGIC = 0.2652031
SQRTHALF = np.sqrt(0.5)
SQRTHALF = (1 / 2) ** (1 / 2)
MAGIC45 = SQRTHALF * MAGIC
MAGICSUM = SQRTHALF + MAGIC45
MAGICDIFF = SQRTHALF - MAGIC45

vertices = np.array([[0.0, -1.0],

@anntzer anntzer Apr 24, 2022 •
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I guess I would just write this is as vertices = np.array([...]) without even bothering with the dtype=float which is unneeded; this also avoids a temporary variable (mostly avoids having to keep track of it mentally). Ditto below.

vertices = ((0.0, -1.0),

[MAGIC, -1.0],
[SQRTHALF-MAGIC45, -SQRTHALF-MAGIC45],
[SQRTHALF, -SQRTHALF],
(MAGIC, -1.0),
(MAGICDIFF, -MAGICSUM),
(SQRTHALF, -SQRTHALF),

[SQRTHALF+MAGIC45, -SQRTHALF+MAGIC45],
[1.0, -MAGIC],
[1.0, 0.0],
(MAGICSUM, -MAGICDIFF),
(1.0, -MAGIC),
(1.0, 0.0),

[1.0, MAGIC],
[SQRTHALF+MAGIC45, SQRTHALF-MAGIC45],
[SQRTHALF, SQRTHALF],
(1.0, MAGIC),
(MAGICSUM, MAGICDIFF),
(SQRTHALF, SQRTHALF),

[SQRTHALF-MAGIC45, SQRTHALF+MAGIC45],
[MAGIC, 1.0],
[0.0, 1.0],
(MAGICDIFF, MAGICSUM),
(MAGIC, 1.0),
(0.0, 1.0),

[-MAGIC, 1.0],
[-SQRTHALF+MAGIC45, SQRTHALF+MAGIC45],
[-SQRTHALF, SQRTHALF],
(-MAGIC, 1.0),
(-MAGICDIFF, MAGICSUM),
(-SQRTHALF, SQRTHALF),

[-SQRTHALF-MAGIC45, SQRTHALF-MAGIC45],
[-1.0, MAGIC],
[-1.0, 0.0],
(-MAGICSUM, MAGICDIFF),
(-1.0, MAGIC),
(-1.0, 0.0),

[-1.0, -MAGIC],
[-SQRTHALF-MAGIC45, -SQRTHALF+MAGIC45],
[-SQRTHALF, -SQRTHALF],
(-1.0, -MAGIC),
(-MAGICSUM, -MAGICDIFF),
(-SQRTHALF, -SQRTHALF),

[-SQRTHALF+MAGIC45, -SQRTHALF-MAGIC45],
[-MAGIC, -1.0],
[0.0, -1.0],
(-MAGICDIFF, -MAGICSUM),
(-MAGIC, -1.0),
(0.0, -1.0),

[0.0, -1.0]],
dtype=float)
(0.0, -1.0))

vertices = np.array(vertices, dtype=float)

codes = [cls.CURVE4] * 26
codes[0] = cls.MOVETO
Expand All @@ -878,31 +881,32 @@ def unit_circle_righthalf(cls):
"""
if cls._unit_circle_righthalf is None:
MAGIC = 0.2652031
SQRTHALF = np.sqrt(0.5)
SQRTHALF = (1 / 2) ** (1 / 2)
MAGIC45 = SQRTHALF * MAGIC
MAGICSUM = SQRTHALF + MAGIC45
MAGICDIFF = SQRTHALF - MAGIC45

vertices = np.array(
[[0.0, -1.0],
vertices = ((0.0, -1.0),

[MAGIC, -1.0],
[SQRTHALF-MAGIC45, -SQRTHALF-MAGIC45],
[SQRTHALF, -SQRTHALF],
(MAGIC, -1.0),
(MAGICDIFF, -MAGICSUM),
(SQRTHALF, -SQRTHALF),

[SQRTHALF+MAGIC45, -SQRTHALF+MAGIC45],
[1.0, -MAGIC],
[1.0, 0.0],
(MAGICSUM, -MAGICDIFF),
(1.0, -MAGIC),
(1.0, 0.0),

[1.0, MAGIC],
[SQRTHALF+MAGIC45, SQRTHALF-MAGIC45],
[SQRTHALF, SQRTHALF],
(1.0, MAGIC),
(MAGICSUM, MAGICDIFF),
(SQRTHALF, SQRTHALF),

[SQRTHALF-MAGIC45, SQRTHALF+MAGIC45],
[MAGIC, 1.0],
[0.0, 1.0],
(MAGICDIFF, MAGICSUM),
(MAGIC, 1.0),
(0.0, 1.0),

[0.0, -1.0]],
(0.0, -1.0))

float)
vertices = np.array(vertices, dtype=float)

codes = np.full(14, cls.CURVE4, dtype=cls.code_type)
codes[0] = cls.MOVETO
Expand Down
4 changes: 2 additions & 2 deletions lib/matplotlib/patheffects.py
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Original file line number Diff line number Diff line change
Expand Up @@ -411,8 +411,8 @@ def __init__(self, offset=(0, 0),
to your right, and 180 behind you.
length : float, default: 1.414
The length of the tick relative to spacing.
Recommended length = 1.414 (sqrt(2)) when angle=45, length=1.0
when angle=90 and length=2.0 when angle=60.
Recommended length = 1.414 (:math:`\\sqrt{2}`) when angle=45,
length=1.0 when angle=90 and length=2.0 when angle=60.
**kwargs
Extra keywords are stored and passed through to
:meth:`AbstractPathEffect._update_gc`.
Expand Down
4 changes: 2 additions & 2 deletions lib/matplotlib/projections/polar.py
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