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##
# Math Test
##
# Performs fuzzy check for equality on methods returning floats
# on the basis of the Math::TOLERANCE constant.
def check(a,b)
a = a.to_f
b = b.to_f
if a.finite? and b.finite?
(a-b).abs < Math::TOLERANCE
else
true
end
end
assert('Math.sin 0') do
check(Math.sin(0), 0)
end
assert('Math.sin PI/2') do
check(Math.sin(Math::PI / 2), 1)
end
assert('Fundamental trig identities') do
result = true
N = 15
N.times do |i|
a = Math::PI / N * i
ca = Math::PI / 2 - a
s = Math.sin(a)
c = Math.cos(a)
t = Math.tan(a)
result &= check(s, Math.cos(ca))
result &= check(t, 1 / Math.tan(ca))
result &= check(s ** 2 + c ** 2, 1)
result &= check(t ** 2 + 1, (1/c) ** 2)
result &= check((1/t) ** 2 + 1, (1/s) ** 2)
end
result
end
assert('Math.erf 0') do
check(Math.erf(0), 0)
end
assert('Math.exp 0') do
check(Math.exp(0), 1.0)
end
assert('Math.exp 1') do
check(Math.exp(1), 2.718281828459045)
end
assert('Math.exp 1.5') do
check(Math.exp(1.5), 4.4816890703380645)
end
assert('Math.log 1') do
check(Math.log(1), 0)
end
assert('Math.log E') do
check(Math.log(Math::E), 1.0)
end
assert('Math.log E**3') do
check(Math.log(Math::E**3), 3.0)
end
assert('Math.log2 1') do
check(Math.log2(1), 0.0)
end
assert('Math.log2 2') do
check(Math.log2(2), 1.0)
end
assert('Math.log10 1') do
check(Math.log10(1), 0.0)
end
assert('Math.log10 10') do
check(Math.log10(10), 1.0)
end
assert('Math.log10 10**100') do
check(Math.log10(10**100), 100.0)
end
assert('Math.cbrt') do
num = [-2.0, -1.0, 0.0, 1.0, 2.0]
cub = [-8, -1, 0, 1, 8]
result = true
cub.each_with_index do |v,i|
result &= check(Math.cbrt(v), num[i])
end
result
end
assert('Math.hypot') do
check(Math.hypot(3, 4), 5.0)
end
assert('Math.frexp 1234') do
n = 1234
fraction, exponent = Math.frexp(n)
check(Math.ldexp(fraction, exponent), n)
end
assert('Math.erf 1') do
check(Math.erf(1), 0.842700792949715)
end
assert('Math.erfc 1') do
check(Math.erfc(1), 0.157299207050285)
end
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