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Commit f3d7ef6

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Get sample_invert working
1 parent 12cab19 commit f3d7ef6

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1 file changed

+47
-98
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1 file changed

+47
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‎main.py‎

Lines changed: 47 additions & 98 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@ def sample_seed(seed, i):
77
Int32MinValue = -2147483648
88
# same as 5 but last loops unwound
99
if seed == Int32MinValue:
10-
subtraction = Int32MinValue
10+
subtraction = MBIG
1111
else:
1212
subtraction = abs(seed)
1313

@@ -109,45 +109,45 @@ def sample_seed(seed, i):
109109
return (add + mul * subtraction) % MBIG
110110

111111
# invert prng, ie: invert_sample(sample_seed(seed, n), n) == x
112-
# def invert_sample(rand, i):
113-
# ret_nums = [
114-
# (1559595546, 1121899819),
115-
# (1755192844, 630111683),
116-
# (1649316166, 1501065279),
117-
# (1198642031, 458365203),
118-
# (442452829, 969558243),
119-
# (1200195957, 1876681249),
120-
# (1945678308, 962194431),
121-
# (949569752, 1077359051),
122-
# (2099272109, 265679591),
123-
# (587775847, 791886952),
124-
# (626863973, 1582116761),
125-
# (1003550677, 1676571504),
126-
# (1358625013, 1476289907),
127-
# (1008269081, 1117239683),
128-
# (2109153755, 1503178135),
129-
# (65212616, 1341148412),
130-
# (1851925803, 902714229),
131-
# (2137491580, 1331438416),
132-
# (1454235444, 58133212),
133-
# (675580731, 831516153),
134-
# (1754296375, 285337308),
135-
# (1821177336, 526856546),
136-
# (2130093701, 362935496),
137-
# (70062080, 750214563),
138-
# (1503113964, 210465667),
139-
# (1130186590, 1381224997),
140-
# (2005789796, 1846331200),
141-
# (1476653312, 1330597961),
142-
# (1174277203, 593162892),
143-
# (174182291, 1729496551),
144-
# (401846963, 792803163),
145-
# (973512717, 565661843),
146-
# (638171722, 863554642),
147-
# (2122881600, 53838754),
148-
# ]
149-
# add, mul = ret_nums[i]
150-
# return (add + mul * subtraction) % MBIG
112+
def invert_sample(rand, i):
113+
ret_nums = [
114+
(1796695496, 1821612595),
115+
(1891800662, 1409645351),
116+
(1610885040, 587487227),
117+
(1696684875, 1455237719),
118+
(2130791390, 767595827),
119+
(1929834895, 129867698),
120+
(2121031305, 1742476897),
121+
(883591791, 2106280948),
122+
(648963137, 1348178552),
123+
(795631511, 1633747307),
124+
(796601229, 1716765365),
125+
(816410995, 1096882805),
126+
(1918475170, 1559029571),
127+
(381881470, 1466324819),
128+
(641551938, 297465690),
129+
(316080314, 75192552),
130+
(270400817, 1823883914),
131+
(1585239219, 729323790),
132+
(2120325298, 2118823669),
133+
(230186630, 726040245),
134+
(547167837, 1241601023),
135+
(2138164393, 2086904121),
136+
(213491428, 315710936),
137+
(729980750, 468302249),
138+
(1512126699, 1259943578),
139+
(1739690517, 1712653821),
140+
(918222596, 653087170),
141+
(157253577, 2061948226),
142+
(970904747, 309988906),
143+
(1801285644, 1451072879),
144+
(584087765, 1485089530),
145+
(1256192415, 888247729),
146+
(1100808447, 2137905013),
147+
(1705889883, 643403504),
148+
]
149+
mul, add = ret_nums[i]
150+
return (add + mul * rand) % MBIG
151151

152152

153153
def sample_all(seed):
@@ -167,63 +167,12 @@ def test_sampel_seed():
167167
if my_r != r:
168168
raise Exception("sample_seed test failed on\n sample(%d)[%d] == %d should be %d" % (seed, ri, my_r, r))
169169

170-
test_sampel_seed()
171-
172-
ret_nums = [
173-
(1559595546, 1121899819),
174-
(1755192844, 630111683),
175-
(1649316166, 1501065279),
176-
(1198642031, 458365203),
177-
(442452829, 969558243),
178-
(1200195957, 1876681249),
179-
(1945678308, 962194431),
180-
(949569752, 1077359051),
181-
(2099272109, 265679591),
182-
(587775847, 791886952),
183-
(626863973, 1582116761),
184-
(1003550677, 1676571504),
185-
(1358625013, 1476289907),
186-
(1008269081, 1117239683),
187-
(2109153755, 1503178135),
188-
(65212616, 1341148412),
189-
(1851925803, 902714229),
190-
(2137491580, 1331438416),
191-
(1454235444, 58133212),
192-
(675580731, 831516153),
193-
(1754296375, 285337308),
194-
(1821177336, 526856546),
195-
(2130093701, 362935496),
196-
(70062080, 750214563),
197-
(1503113964, 210465667),
198-
(1130186590, 1381224997),
199-
(2005789796, 1846331200),
200-
(1476653312, 1330597961),
201-
(1174277203, 593162892),
202-
(174182291, 1729496551),
203-
(401846963, 792803163),
204-
(973512717, 565661843),
205-
(638171722, 863554642),
206-
(2122881600, 53838754),
207-
]
208-
invert_nums = []
209-
for add, mul in ret_nums:
210-
# giving rand = add + mul * seed mod MBIG
211-
# produce the inverted numer
212-
# ie:
213-
# rand - add = mul * seed
214-
# (rand - add) * mul^-1 = seed
215-
# rand * mul^-1 - add*mul^-1 = seed
216-
# where mul^-1 is inv_mul
217-
# -1 * add*mul^-1 is inv_add
218-
# inv_mul is found using fermats little therom: https://en.wikipedia.org/wiki/Fermat%27s_little_theorem
219-
# since MBIG is prime (Mersenne prime 2^31-1)
220-
inv_mul = pow(mul, MBIG - 2, MBIG)
221-
222-
# double check it's inverted
223-
assert((mul * inv_mul) % MBIG == 1)
224-
inv_add = (-1 * add * inv_mul) % MBIG
170+
for seed in range(4096 * 16):
171+
for i in range(34):
172+
r = sample_seed(seed, i)
173+
inv_r = invert_sample(r, i)
174+
if inv_r != seed:
175+
raise Exception("Inversion test failed on seed: %d rand: %d i: %d inv: %d" % (seed, r, i, inv_r))
225176

226-
invert_nums.append((inv_mul, inv_add))
177+
test_sampel_seed()
227178

228-
print(invert_nums)
229-
# [(1796695496, 1821612595), (1891800662, 1409645351), (1610885040, 587487227), (1696684875, 1455237719), (2130791390, 767595827), (1929834895, 129867698), (2121031305, 1742476897), (883591791, 2106280948), (648963137, 1348178552), (795631511, 1633747307), (796601229, 1716765365), (816410995, 1096882805), (1918475170, 1559029571), (381881470, 1466324819), (641551938, 297465690), (316080314, 75192552), (270400817, 1823883914), (1585239219, 729323790), (2120325298, 2118823669), (230186630, 726040245), (547167837, 1241601023), (2138164393, 2086904121), (213491428, 315710936), (729980750, 468302249), (1512126699, 1259943578), (1739690517, 1712653821), (918222596, 653087170), (157253577, 2061948226), (970904747, 309988906), (1801285644, 1451072879), (584087765, 1485089530), (1256192415, 888247729), (1100808447, 2137905013), (1705889883, 643403504)]

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