test_functions.py 文件源码

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)