File size: 6,329 Bytes
6a86ad5
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
from functools import singledispatch

from sympy.core.symbol import Dummy
from sympy.functions.elementary.exponential import exp
from sympy.utilities.lambdify import lambdify
from sympy.external import import_module
from sympy.stats import DiscreteDistributionHandmade
from sympy.stats.crv import SingleContinuousDistribution
from sympy.stats.crv_types import ChiSquaredDistribution, ExponentialDistribution, GammaDistribution, \
    LogNormalDistribution, NormalDistribution, ParetoDistribution, UniformDistribution, BetaDistribution, \
    StudentTDistribution, CauchyDistribution
from sympy.stats.drv_types import GeometricDistribution, LogarithmicDistribution, NegativeBinomialDistribution, \
    PoissonDistribution, SkellamDistribution, YuleSimonDistribution, ZetaDistribution
from sympy.stats.frv import SingleFiniteDistribution


scipy = import_module("scipy", import_kwargs={'fromlist':['stats']})


@singledispatch
def do_sample_scipy(dist, size, seed):
    return None


# CRV

@do_sample_scipy.register(SingleContinuousDistribution)
def _(dist: SingleContinuousDistribution, size, seed):
    # if we don't need to make a handmade pdf, we won't
    import scipy.stats

    z = Dummy('z')
    handmade_pdf = lambdify(z, dist.pdf(z), ['numpy', 'scipy'])

    class scipy_pdf(scipy.stats.rv_continuous):
        def _pdf(dist, x):
            return handmade_pdf(x)

    scipy_rv = scipy_pdf(a=float(dist.set._inf),
                         b=float(dist.set._sup), name='scipy_pdf')
    return scipy_rv.rvs(size=size, random_state=seed)


@do_sample_scipy.register(ChiSquaredDistribution)
def _(dist: ChiSquaredDistribution, size, seed):
    # same parametrisation
    return scipy.stats.chi2.rvs(df=float(dist.k), size=size, random_state=seed)


@do_sample_scipy.register(ExponentialDistribution)
def _(dist: ExponentialDistribution, size, seed):
    # https://docs.scipy.org/doc/scipy/reference/generated/scipy.stats.expon.html#scipy.stats.expon
    return scipy.stats.expon.rvs(scale=1 / float(dist.rate), size=size, random_state=seed)


@do_sample_scipy.register(GammaDistribution)
def _(dist: GammaDistribution, size, seed):
    # https://stackoverflow.com/questions/42150965/how-to-plot-gamma-distribution-with-alpha-and-beta-parameters-in-python
    return scipy.stats.gamma.rvs(a=float(dist.k), scale=float(dist.theta), size=size, random_state=seed)


@do_sample_scipy.register(LogNormalDistribution)
def _(dist: LogNormalDistribution, size, seed):
    # https://docs.scipy.org/doc/scipy/reference/generated/scipy.stats.lognorm.html
    return scipy.stats.lognorm.rvs(scale=float(exp(dist.mean)), s=float(dist.std), size=size, random_state=seed)


@do_sample_scipy.register(NormalDistribution)
def _(dist: NormalDistribution, size, seed):
    return scipy.stats.norm.rvs(loc=float(dist.mean), scale=float(dist.std), size=size, random_state=seed)


@do_sample_scipy.register(ParetoDistribution)
def _(dist: ParetoDistribution, size, seed):
    # https://stackoverflow.com/questions/42260519/defining-pareto-distribution-in-python-scipy
    return scipy.stats.pareto.rvs(b=float(dist.alpha), scale=float(dist.xm), size=size, random_state=seed)


@do_sample_scipy.register(StudentTDistribution)
def _(dist: StudentTDistribution, size, seed):
    return scipy.stats.t.rvs(df=float(dist.nu), size=size, random_state=seed)


@do_sample_scipy.register(UniformDistribution)
def _(dist: UniformDistribution, size, seed):
    # https://docs.scipy.org/doc/scipy/reference/generated/scipy.stats.uniform.html
    return scipy.stats.uniform.rvs(loc=float(dist.left), scale=float(dist.right - dist.left), size=size, random_state=seed)


@do_sample_scipy.register(BetaDistribution)
def _(dist: BetaDistribution, size, seed):
    # same parametrisation
    return scipy.stats.beta.rvs(a=float(dist.alpha), b=float(dist.beta), size=size, random_state=seed)


@do_sample_scipy.register(CauchyDistribution)
def _(dist: CauchyDistribution, size, seed):
    return scipy.stats.cauchy.rvs(loc=float(dist.x0), scale=float(dist.gamma), size=size, random_state=seed)


# DRV:

@do_sample_scipy.register(DiscreteDistributionHandmade)
def _(dist: DiscreteDistributionHandmade, size, seed):
    from scipy.stats import rv_discrete

    z = Dummy('z')
    handmade_pmf = lambdify(z, dist.pdf(z), ['numpy', 'scipy'])

    class scipy_pmf(rv_discrete):
        def _pmf(dist, x):
            return handmade_pmf(x)

    scipy_rv = scipy_pmf(a=float(dist.set._inf), b=float(dist.set._sup),
                         name='scipy_pmf')
    return scipy_rv.rvs(size=size, random_state=seed)


@do_sample_scipy.register(GeometricDistribution)
def _(dist: GeometricDistribution, size, seed):
    return scipy.stats.geom.rvs(p=float(dist.p), size=size, random_state=seed)


@do_sample_scipy.register(LogarithmicDistribution)
def _(dist: LogarithmicDistribution, size, seed):
    return scipy.stats.logser.rvs(p=float(dist.p), size=size, random_state=seed)


@do_sample_scipy.register(NegativeBinomialDistribution)
def _(dist: NegativeBinomialDistribution, size, seed):
    return scipy.stats.nbinom.rvs(n=float(dist.r), p=float(dist.p), size=size, random_state=seed)


@do_sample_scipy.register(PoissonDistribution)
def _(dist: PoissonDistribution, size, seed):
    return scipy.stats.poisson.rvs(mu=float(dist.lamda), size=size, random_state=seed)


@do_sample_scipy.register(SkellamDistribution)
def _(dist: SkellamDistribution, size, seed):
    return scipy.stats.skellam.rvs(mu1=float(dist.mu1), mu2=float(dist.mu2), size=size, random_state=seed)


@do_sample_scipy.register(YuleSimonDistribution)
def _(dist: YuleSimonDistribution, size, seed):
    return scipy.stats.yulesimon.rvs(alpha=float(dist.rho), size=size, random_state=seed)


@do_sample_scipy.register(ZetaDistribution)
def _(dist: ZetaDistribution, size, seed):
    return scipy.stats.zipf.rvs(a=float(dist.s), size=size, random_state=seed)


# FRV:

@do_sample_scipy.register(SingleFiniteDistribution)
def _(dist: SingleFiniteDistribution, size, seed):
    # scipy can handle with custom distributions

    from scipy.stats import rv_discrete
    density_ = dist.dict
    x, y = [], []
    for k, v in density_.items():
        x.append(int(k))
        y.append(float(v))
    scipy_rv = rv_discrete(name='scipy_rv', values=(x, y))
    return scipy_rv.rvs(size=size, random_state=seed)