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Diffstat (limited to 'numpy/random/_examples/cython/extending_distributions.pyx')
-rw-r--r-- | numpy/random/_examples/cython/extending_distributions.pyx | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/numpy/random/_examples/cython/extending_distributions.pyx b/numpy/random/_examples/cython/extending_distributions.pyx new file mode 100644 index 000000000..d17da45c1 --- /dev/null +++ b/numpy/random/_examples/cython/extending_distributions.pyx @@ -0,0 +1,63 @@ +#!/usr/bin/env python +#cython: language_level=3 +""" +This file shows how the to use a BitGenerator to create a distribution. +""" +import numpy as np +cimport numpy as np +cimport cython +from cpython.pycapsule cimport PyCapsule_IsValid, PyCapsule_GetPointer +from numpy.random._bit_generator cimport bitgen_t +from numpy.random import PCG64 + + +@cython.boundscheck(False) +@cython.wraparound(False) +def uniforms(Py_ssize_t n): + """ Create an array of `n` uniformly distributed doubles. + A 'real' distribution would want to process the values into + some non-uniform distribution + """ + cdef Py_ssize_t i + cdef bitgen_t *rng + cdef const char *capsule_name = "BitGenerator" + cdef double[::1] random_values + + x = PCG64() + capsule = x.capsule + # Optional check that the capsule if from a BitGenerator + if not PyCapsule_IsValid(capsule, capsule_name): + raise ValueError("Invalid pointer to anon_func_state") + # Cast the pointer + rng = <bitgen_t *> PyCapsule_GetPointer(capsule, capsule_name) + random_values = np.empty(n, dtype='float64') + with x.lock, nogil: + for i in range(n): + # Call the function + random_values[i] = rng.next_double(rng.state) + randoms = np.asarray(random_values) + + return randoms + +# cython example 2 + +@cython.boundscheck(False) +@cython.wraparound(False) +def uint16_uniforms(Py_ssize_t n): + cdef Py_ssize_t i + cdef bitgen_t *rng + cdef const char *capsule_name = "BitGenerator" + cdef double[::1] random_values + + x = PCG64() + capsule = x.capsule + if not PyCapsule_IsValid(capsule, capsule_name): + raise ValueError("Invalid pointer to anon_func_state") + rng = <bitgen_t *> PyCapsule_GetPointer(capsule, capsule_name) + random_values = np.empty(n, dtype='uint32') + # Best practice is to release GIL and acquire the lock + with x.lock, nogil: + for i in range(n): + random_values[i] = rng.next_uint32(rng.state) + randoms = np.asarray(random_values) + return randoms |