def random_standard_normal_f(bitgen):
while 1:
r = next_uint32(bitgen)
idx = r & 0xff
sign = (r >> 8) & 0x1
rabs = (r >> 9) & 0x0007fffff
x = float32(float32(rabs) * wi_float[idx])
if (sign & 0x1):
x = -x
if (rabs < ki_float[idx]):
return x
if (idx == 0):
while 1:
xx = float32(-ziggurat_nor_inv_r_f *
np_log1pf(-next_float(bitgen)))
yy = float32(-np_log1pf(-next_float(bitgen)))
if (float32(yy + yy) > float32(xx * xx)):
if ((rabs >> 8) & 0x1):
return -float32(ziggurat_nor_r_f + xx)
else:
return float32(ziggurat_nor_r_f + xx)
else:
if (((fi_float[idx - 1] - fi_float[idx]) * next_float(bitgen) +
fi_float[idx]) < float32(np.exp(-float32(0.5) * x * x))):
return x
def random_bounded_uint64_fill(bitgen, low, rng, size, dtype):
"""
Returns a new array of given size with 64 bit integers
bounded by given interval.
"""
out = np.empty(size, dtype=dtype)
if rng == 0:
for i in np.ndindex(size):
out[i] = low
elif rng <= 0xFFFFFFFF:
if (rng == 0xFFFFFFFF):
for i in np.ndindex(size):
out[i] = low + next_uint32(bitgen)
else:
for i in np.ndindex(size):
out[i] = low + buffered_bounded_lemire_uint32(bitgen, rng)
elif (rng == 0xFFFFFFFFFFFFFFFF):
for i in np.ndindex(size):
out[i] = low + next_uint64(bitgen)
else:
for i in np.ndindex(size):
out[i] = low + bounded_lemire_uint64(bitgen, rng)
return out
def buffered_uint16(bitgen, bcnt, buf):
if not bcnt:
buf = next_uint32(bitgen)
bcnt = 1
else:
buf >>= 16
bcnt -= 1
return uint16(buf), bcnt, buf
def buffered_uint8(bitgen, bcnt, buf):
if not bcnt:
buf = next_uint32(bitgen)
bcnt = 3
else:
buf >>= 8
bcnt -= 1
return uint8(buf), bcnt, buf
def buffered_bounded_bool(bitgen, off, rng, bcnt, buf):
if (rng == 0):
return off, bcnt, buf
if not bcnt:
buf = next_uint32(bitgen)
bcnt = 31
else:
buf >>= 1
bcnt -= 1
return ((buf & 1) != 0), bcnt, buf
def buffered_bounded_lemire_uint32(bitgen, rng):
"""
Generates a random unsigned 32 bit integer bounded
within a given interval using Lemire's rejection.
"""
rng_excl = uint32(rng) + uint32(1)
assert (rng != 0xFFFFFFFF)
# Generate a scaled random number.
m = uint64(next_uint32(bitgen)) * uint64(rng_excl)
# Rejection sampling to remove any bias
leftover = m & 0xFFFFFFFF
if (leftover < rng_excl):
# `rng_excl` is a simple upper bound for `threshold`.
threshold = (UINT32_MAX - rng) % rng_excl
while (leftover < threshold):
m = uint64(next_uint32(bitgen)) * uint64(rng_excl)
leftover = m & 0xFFFFFFFF
return (m >> 32)
def random_standard_exponential_f(bitgen):
while 1:
ri = next_uint32(bitgen)
ri >>= 1
idx = ri & 0xFF
ri >>= 8
x = float32(float32(ri) * we_float[idx])
if (ri < ke_float[idx]):
return x
else:
if (idx == 0):
return float32(ziggurat_exp_r_f -
float32(np_log1pf(-next_float(bitgen))))
elif ((fe_float[idx - 1] - fe_float[idx]) * next_float(bitgen) +
fe_float[idx] < float32(np.exp(float32(-x)))):
return x
def random_bounded_uint32_fill(bitgen, low, rng, size, dtype):
"""
Returns a new array of given size with 32 bit integers
bounded by given interval.
"""
out = np.empty(size, dtype=dtype)
if rng == 0:
for i in np.ndindex(size):
out[i] = low
elif rng == 0xFFFFFFFF:
# Lemire32 doesn't support rng = 0xFFFFFFFF.
for i in np.ndindex(size):
out[i] = low + next_uint32(bitgen)
else:
for i in np.ndindex(size):
out[i] = low + buffered_bounded_lemire_uint32(bitgen, rng)
return out
