# Python math.erfc() Examples

The following are code examples for showing how to use math.erfc(). They are extracted from open source Python projects. You can vote up the examples you like or vote down the ones you don't like. You can also save this page to your account.

Example 1
 Project: sp800_22_tests   Author: dj-on-github   File: sp800_22_runs_test.py    (license) View Source Project 7 votes  ```def runs_test(bits):
n = len(bits)
zeroes,ones = count_ones_zeroes(bits)

prop = float(ones)/float(n)
print "  prop ",prop

tau = 2.0/math.sqrt(n)
print "  tau ",tau

if abs(prop-0.5) > tau:
return (False,0.0,None)

vobs = 1.0
for i in xrange(n-1):
if bits[i] != bits[i+1]:
vobs += 1.0

print "  vobs ",vobs

p = math.erfc(abs(vobs - (2.0*n*prop*(1.0-prop)))/(2.0*math.sqrt(2.0*n)*prop*(1-prop) ))
success = (p >= 0.01)
return (success,p,None) ```
Example 2
 Project: sp800_22_tests   Author: dj-on-github   File: sp800_22_monobit_test.py    (license) View Source Project 5 votes  ```def monobit_test(bits):
n = len(bits)

zeroes,ones = count_ones_zeroes(bits)
s = abs(ones-zeroes)
print "  Ones count   = %d" % ones
print "  Zeroes count = %d" % zeroes

p = math.erfc(float(s)/(math.sqrt(float(n)) * math.sqrt(2.0)))

success = (p >= 0.1)
return (success,p,None) ```
Example 3
 Project: sp800_22_tests   Author: dj-on-github   File: sp800_22_dft_test.py    (license) View Source Project 5 votes  ```def dft_test(bits):
n = len(bits)
if (n % 2) == 1:        # Make it an even number
bits = bits[:-1]

ts = list()             # Convert to +1,-1
for bit in bits:
ts.append((bit*2)-1)

ts_np = numpy.array(ts)
fs = numpy.fft.fft(ts_np)  # Compute DFT

mags = abs(fs)[:n/2] # Compute magnitudes of first half of sequence

T = math.sqrt(math.log(1.0/0.05)*n) # Compute upper threshold
N0 = 0.95*n/2.0
print "  N0 = %f" % N0

N1 = 0.0   # Count the peaks above the upper theshold
for mag in mags:
if mag < T:
N1 += 1.0
print "  N1 = %f" % N1
d = (N1 - N0)/math.sqrt((n*0.95*0.05)/4) # Compute the P value
p = math.erfc(abs(d)/math.sqrt(2))

success = (p >= 0.01)
return (success,p,None) ```
Example 4
 Project: sp800_22_tests   Author: dj-on-github   File: sp800_22_cumulative_sums_test.py    (license) View Source Project 5 votes  ```def normcdf(n):
return 0.5 * math.erfc(-n * math.sqrt(0.5)) ```
Example 5
 Project: CCIT   Author: rajatsen91   File: CCIT.py    (license) View Source Project 5 votes  ```def pvalue(x,sigma):

return 0.5*erfc(x/(sigma*np.sqrt(2))) ```
Example 6
 Project: SparseArray   Author: INGEOTEC   File: test_sparse_array.py    (license) View Source Project 4 votes  ```def test_one():
from math import sin, cos, tan, asin, acos, atan
from math import sinh, cosh, tanh, asinh, acosh, atanh
from math import exp, expm1, log, log10, log1p, sqrt, lgamma
from math import fabs, ceil, floor, trunc, erf, erfc
try:
from math import log2
except ImportError:
def log2(x):
return log(x) / log(2)

def wrapper(f, v):
try:
return f(v)
except ValueError:
if f == sqrt:
return float('nan')
if v >= 0:
return float('inf')
else:
return -float('inf')

def compare(a, b):
if isfinite(a) and isfinite(b):
return assert_almost_equals(a, b)
return str(a) == str(b)

for f in [sin, cos, tan, asin, acos, atan,
sinh, cosh, tanh, asinh, acosh, atanh,
exp, expm1, log, log2, log10, log1p, sqrt,
lgamma,
fabs, ceil, floor, trunc,
erf, erfc]:
for p in [0.5, 1]:
a = random_lst(p=p)
b = SparseArray.fromlist(a)
c = getattr(b, f.__name__)()
res = [wrapper(f, x) for x in a]
index = [k for k, v in enumerate(res) if v != 0]
res = [x for x in res if x != 0]
print(f, p, c.non_zero, len(res))
assert c.non_zero == len(res)
[assert_almost_equals(v, w) for v, w in zip(index,
c.index)]
[compare(v, w) for v, w in zip(res,
c.data)] ```