def test_log():
mp.dps = 15
assert log(1) == 0
for x in [0.5, 1.5, 2.0, 3.0, 100, 10**50, 1e-50]:
assert log(x).ae(math.log(x))
assert log(x, x) == 1
assert log(1024, 2) == 10
assert log(10**1234, 10) == 1234
assert log(2+2j).ae(cmath.log(2+2j))
# Accuracy near 1
assert (log(0.6+0.8j).real*10**17).ae(2.2204460492503131)
assert (log(0.6-0.8j).real*10**17).ae(2.2204460492503131)
assert (log(0.8-0.6j).real*10**17).ae(2.2204460492503131)
assert (log(1+1e-8j).real*10**16).ae(0.5)
assert (log(1-1e-8j).real*10**16).ae(0.5)
assert (log(-1+1e-8j).real*10**16).ae(0.5)
assert (log(-1-1e-8j).real*10**16).ae(0.5)
assert (log(1j+1e-8).real*10**16).ae(0.5)
assert (log(1j-1e-8).real*10**16).ae(0.5)
assert (log(-1j+1e-8).real*10**16).ae(0.5)
assert (log(-1j-1e-8).real*10**16).ae(0.5)
assert (log(1+1e-40j).real*10**80).ae(0.5)
assert (log(1j+1e-40).real*10**80).ae(0.5)
# Huge
assert log(ldexp(1.234,10**20)).ae(log(2)*1e20)
assert log(ldexp(1.234,10**200)).ae(log(2)*1e200)
# Some special values
assert log(mpc(0,0)) == mpc(-inf,0)
assert isnan(log(mpc(nan,0)).real)
assert isnan(log(mpc(nan,0)).imag)
assert isnan(log(mpc(0,nan)).real)
assert isnan(log(mpc(0,nan)).imag)
assert isnan(log(mpc(nan,1)).real)
assert isnan(log(mpc(nan,1)).imag)
assert isnan(log(mpc(1,nan)).real)
assert isnan(log(mpc(1,nan)).imag)
python类log()的实例源码
def test_complex_functions():
for x in (list(range(10)) + list(range(-10,0))):
for y in (list(range(10)) + list(range(-10,0))):
z = complex(x, y)/4.3 + 0.01j
assert exp(mpc(z)).ae(cmath.exp(z))
assert log(mpc(z)).ae(cmath.log(z))
assert cos(mpc(z)).ae(cmath.cos(z))
assert sin(mpc(z)).ae(cmath.sin(z))
assert tan(mpc(z)).ae(cmath.tan(z))
assert sinh(mpc(z)).ae(cmath.sinh(z))
assert cosh(mpc(z)).ae(cmath.cosh(z))
assert tanh(mpc(z)).ae(cmath.tanh(z))
def test_aliases():
assert ln(7) == log(7)
assert log10(3.75) == log(3.75,10)
assert degrees(5.6) == 5.6 / degree
assert radians(5.6) == 5.6 * degree
assert power(-1,0.5) == j
assert fmod(25,7) == 4.0 and isinstance(fmod(25,7), mpf)
def test_misc_bugs():
# test that this doesn't raise an exception
mp.dps = 1000
log(1302)
mp.dps = 15
def log10(ctx, x):
return ctx.log(x, 10)
def _mathfun_n(f_real, f_complex):
def f(*args, **kwargs):
try:
return f_real(*(float(x) for x in args))
except (TypeError, ValueError):
return f_complex(*(complex(x) for x in args))
f.__name__ = f_real.__name__
return f
# Workaround for non-raising log and sqrt in Python 2.5 and 2.4
# on Unix system
def math_log(x):
if x <= 0.0:
raise ValueError("math domain error")
return math.log(x)
def my_log(x, y = None):
if y is None:
return log(x)
else:
return log(y, x)
def log(x, y = None):
if y is None:
return math_lib.log(x)
else:
return math_lib.log(y, x)
def test_log():
mp.dps = 15
assert log(1) == 0
for x in [0.5, 1.5, 2.0, 3.0, 100, 10**50, 1e-50]:
assert log(x).ae(math.log(x))
assert log(x, x) == 1
assert log(1024, 2) == 10
assert log(10**1234, 10) == 1234
assert log(2+2j).ae(cmath.log(2+2j))
# Accuracy near 1
assert (log(0.6+0.8j).real*10**17).ae(2.2204460492503131)
assert (log(0.6-0.8j).real*10**17).ae(2.2204460492503131)
assert (log(0.8-0.6j).real*10**17).ae(2.2204460492503131)
assert (log(1+1e-8j).real*10**16).ae(0.5)
assert (log(1-1e-8j).real*10**16).ae(0.5)
assert (log(-1+1e-8j).real*10**16).ae(0.5)
assert (log(-1-1e-8j).real*10**16).ae(0.5)
assert (log(1j+1e-8).real*10**16).ae(0.5)
assert (log(1j-1e-8).real*10**16).ae(0.5)
assert (log(-1j+1e-8).real*10**16).ae(0.5)
assert (log(-1j-1e-8).real*10**16).ae(0.5)
assert (log(1+1e-40j).real*10**80).ae(0.5)
assert (log(1j+1e-40).real*10**80).ae(0.5)
# Huge
assert log(ldexp(1.234,10**20)).ae(log(2)*1e20)
assert log(ldexp(1.234,10**200)).ae(log(2)*1e200)
# Some special values
assert log(mpc(0,0)) == mpc(-inf,0)
assert isnan(log(mpc(nan,0)).real)
assert isnan(log(mpc(nan,0)).imag)
assert isnan(log(mpc(0,nan)).real)
assert isnan(log(mpc(0,nan)).imag)
assert isnan(log(mpc(nan,1)).real)
assert isnan(log(mpc(nan,1)).imag)
assert isnan(log(mpc(1,nan)).real)
assert isnan(log(mpc(1,nan)).imag)
def test_complex_functions():
for x in (list(range(10)) + list(range(-10,0))):
for y in (list(range(10)) + list(range(-10,0))):
z = complex(x, y)/4.3 + 0.01j
assert exp(mpc(z)).ae(cmath.exp(z))
assert log(mpc(z)).ae(cmath.log(z))
assert cos(mpc(z)).ae(cmath.cos(z))
assert sin(mpc(z)).ae(cmath.sin(z))
assert tan(mpc(z)).ae(cmath.tan(z))
assert sinh(mpc(z)).ae(cmath.sinh(z))
assert cosh(mpc(z)).ae(cmath.cosh(z))
assert tanh(mpc(z)).ae(cmath.tanh(z))
def test_aliases():
assert ln(7) == log(7)
assert log10(3.75) == log(3.75,10)
assert degrees(5.6) == 5.6 / degree
assert radians(5.6) == 5.6 * degree
assert power(-1,0.5) == j
assert fmod(25,7) == 4.0 and isinstance(fmod(25,7), mpf)
def test_misc_bugs():
# test that this doesn't raise an exception
mp.dps = 1000
log(1302)
mp.dps = 15
def log10(ctx, x):
return ctx.log(x, 10)
def _mathfun_n(f_real, f_complex):
def f(*args, **kwargs):
try:
return f_real(*(float(x) for x in args))
except (TypeError, ValueError):
return f_complex(*(complex(x) for x in args))
f.__name__ = f_real.__name__
return f
# Workaround for non-raising log and sqrt in Python 2.5 and 2.4
# on Unix system
def math_log(x):
if x <= 0.0:
raise ValueError("math domain error")
return math.log(x)
def mathlog(a):return mathclog(a).real
def mathlog(a):return mathclog(a).real
def mathlog(a):return mathclog(a).real
def computeBaseClassifierCoefficient(self, classifierIdx):
'''
???????????????(?0??)???????????? alpha ?
:param classifierIdx: ???????(?0??)
:return:
'''
self.alphaList[classifierIdx] = (1.0 / 2 * \
cmath.log((1.0-self.eList[classifierIdx])/self.eList[classifierIdx], cmath.e)\
).real
