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Contents
module Math
# Levi-Civita symbol of +i+, +j+, and +k+ - 1 if (+i+, +j+, +k+)
# is (1, 2, 3), (2, 3, 1), or (3, 1, 2), -1 if it is (1, 3, 2),
# (2, 1, 3), or (3, 2, 1), 0 as long as +i+, +j+, and +k+ are
# all elements of {1, 2, 3}, otherwise returns <code>nil</code>.
def self.epsilon(i, j, k)
i = Integer(i)
return nil if i < 1 or i > 3
j = Integer(j)
return nil if j < 1 or j > 3
k = Integer(k)
return nil if k < 1 or k > 3
case i * 16 + j * 4 + k
when 27, 45, 54 then return 1
when 30, 39, 57 then return -1
end
0
end
end
Version data entries
9 entries across 8 versions & 2 rubygems