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32 bit direct field now works correctly.

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This commit is contained in:
Ethan L. Miller 2015-11-13 00:52:13 -08:00
parent a6ab689d84
commit 5b186d41c4
1 changed files with 16 additions and 13 deletions
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29
galois.py
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@ -37,7 +37,7 @@ class GaloisNumber:
the field with which the GaloisNumber instance was defined.
'''
if v > self.field.size:
raise GaloisException ("Value {0} is outside field".format (value))
raise GaloisException ("Value {0} is outside field".format (v))
self.value = v
def __add__ (self, other):
@ -171,9 +171,9 @@ class GaloisFieldDirect:
There only needs to be one instantiation of the field for a given set of parameters,
but elements from different field instances with the same parameters may be mixed.
'''
field_widths = (4, 8, 12, 16)
poly_defaults = {4: 0x13, 8: 0x11d, 12:0x1053, 16: 0x1100b}
multiply_test_size = 10000
field_widths = (4, 8, 12, 16, 32)
poly_defaults = {4: 0x13, 8: 0x11d, 12:0x1053, 16: 0x1100b, 32: 0x1000000c5}
max_test_size = 5000
def __init__ (self, bits, primitive_polynomial = None, repr_prefix = 'G', alpha = 1):
'''
Create a Galois field using direct arithmetic. No log tables or inverses to
@ -241,14 +241,15 @@ class GaloisFieldDirect:
v = GaloisNumber (self)
g_0 = GaloisNumber (self, 0)
g_1 = GaloisNumber (self, 1)
for i in range (self.size):
v.assign (i)
if i == 0: continue
small_field = self.size < self.max_test_size
n_tests = (self.size - 1) if small_field else self.max_test_size
for i in range (0, n_tests):
v.assign ((i if small_field else random.randint (0, self.size - 2)) + 1)
assert v * ~v == mul_identity, "Multiplicative inverse failed at {}".format (i)
assert g_0 - v == -v, "Additive inverse failed at {}".format (i)
assert v * g_1 == v, "Multiplicative identity failed at {}".format (i)
vb = GaloisNumber (self)
for a in range (1, self.multiply_test_size):
for a in range (1, self.max_test_size):
v.assign (random.randint (1, self.size - 1))
vb.assign (random.randint (1, self.size - 1))
product = v * vb
@ -257,17 +258,19 @@ class GaloisFieldDirect:
return True
if __name__ == '__main__':
print '\nTesting direct fields...........'
for width in GaloisFieldDirect.field_widths:
field = GaloisFieldDirect (width)
g0 = GaloisNumber (field, 5)
g0 = GaloisNumber (field, 2)
g1 = GaloisNumber (field, 7)
print g0 + g1
print '{0} + {1} = {2}'.format (g0, g1, g0 + g1)
if field.self_test ():
print "{0} bit field (direct) passed!".format (width)
print '\nTesting log fields...........'
for width in GaloisFieldLog.field_widths:
field = GaloisFieldLog (width)
g0 = GaloisNumber (field, 2)
g1 = GaloisNumber (field, 7)
print '{0} + {1} = {2}'.format (g0, g1, g0 + g1)
if field.self_test ():
print "{0} bit field (log) passed!".format (width)
g0 = GaloisNumber (field, 5)
g1 = GaloisNumber (field, 7)
print g0 + g1