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Add great circle distance

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rstiskalek 2023-10-23 16:01:26 +01:00
parent 45f6584493
commit fb2ac576ea
2 changed files with 22 additions and 1 deletions
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3
csiborgtools/__init__.py
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@ -16,7 +16,8 @@ from csiborgtools import clustering, field, match, read, summary
from .utils import (center_of_mass, delta2ncells, number_counts, # noqa
periodic_distance, periodic_distance_two_points, # noqa
binned_statistic, cosine_similarity, fprint) # noqa
binned_statistic, cosine_similarity, fprint, # noqa
great_circle_distance) # noqa
# Arguments to csiborgtools.read.Paths.

20
csiborgtools/utils.py
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@ -148,6 +148,26 @@ def radec_to_cartesian(X):
]).T
@jit(nopython=True, fastmath=True, boundscheck=False)
def great_circle_distance(x1, x2):
"""
Great circle distance between two points on a sphere, defined by RA and
dec, both in degrees.
"""
ra1, dec1 = x1
ra2, dec2 = x2
ra1 *= numpy.pi / 180
dec1 *= numpy.pi / 180
ra2 *= numpy.pi / 180
dec2 *= numpy.pi / 180
return 180 / numpy.pi * numpy.arccos(
numpy.sin(dec1) * numpy.sin(dec2)
+ numpy.cos(dec1) * numpy.cos(dec2) * numpy.cos(ra1 - ra2)
)
def cosine_similarity(x, y):
r"""
Calculate the cosine similarity between two Cartesian vectors. Defined