From ce05175372a9ddca1a225db0765ace1127a39293 Mon Sep 17 00:00:00 2001
From: Nicholas <nbnoll@eml.cc>
Date: Fri, 12 Nov 2021 09:22:01 -0800
Subject: chore: simplified organizational structure

---
 sys/base/rng/poisson.c | 126 -------------------------------------------------
 1 file changed, 126 deletions(-)
 delete mode 100644 sys/base/rng/poisson.c

(limited to 'sys/base/rng/poisson.c')

diff --git a/sys/base/rng/poisson.c b/sys/base/rng/poisson.c
deleted file mode 100644
index 3ec15c9..0000000
--- a/sys/base/rng/poisson.c
+++ /dev/null
@@ -1,126 +0,0 @@
-#include "internal.h"
-
-/*
- * Ahrens, J. H., & Dieter, U. (1982).
- * Computer Generation of Poisson Deviates from Modified Normal Distributions.
- */
-static double factorial[10] = {1., 1., 2., 6., 24., 120., 720., 5040., 40320., 362880.};
-static double coeffs[9] = {
-    -.500000000, +.333333333, -.249999856,
-    +.200011780, -.166684875, +.142187833,
-    -.124196313, +.125005956, -.114265030,
-};
-
-static inline
-double
-log1pmx(double x, double off)
-{
-    int i;
-    double r, t;
-
-    if(-0.25 < x && x < 0.25) {
-        r = 0;
-        t = 1;
-        for(i=0;i<arrlen(coeffs);i++) {
-            r += coeffs[i]*t;
-            t *= x;
-        }
-
-        return x*x*r;
-    }
-    return log(1+x) - off;
-}
-
-static inline
-double
-procf(double mu, double s, int64 K, double *px, double *py, double *fx, double *fy)
-{
-    double d, V, X;
-    double w, b1, b2, c1, c2, c3, c0, c;
-
-    w  = 0.3989422804014327/s;
-    b1 = 0.041666666666666664/mu;
-    b2 = 0.3*b1*b1;
-    c3 = 0.14285714285714285*b1*b2;
-    c2 = b2 - 15.*c3;
-    c1 = b1 - 6.*b2 + 45.*c3;
-    c0 = 1 - b1 + 3.*b2 - 15.*c3;
-    c  = .1069/mu;
-
-    if(K < 10) {
-        *px = -mu;
-        *py = pow(mu,K) / factorial[K];
-    }else{
-        d = 0.08333333333333333/K;
-        d = d - 4.8*d*d*d;
-        V = (mu - K) / K;
-
-        *px = K*log1pmx(V,mu-K) - d;
-        *py = 0.3989422804014327/sqrt(K);
-    }
-
-    X = (K - mu + 0.5)/s;
-    *fx = -0.5*X*X;
-    *fy = w*(((c3*X*X + c2)*X*X + c1)*X*X + c0);
-
-    return c;
-}
-
-static inline
-uint64
-bigpoisson(double mu)
-{
-    int64  L,K;
-    double G,s,d,U,E,T;
-    double px,py,fx,fy,c;
-
-    s = sqrt(mu);
-    d = 6*mu*mu;
-    L = floor(mu - 1.1484);
-
-stepN:
-    G = mu + s*rng·normal();
-    K = floor(G);
-    if(K<0)
-        goto stepP;
-stepI:
-    if(K>=L)
-        return K;
-stepS:
-    U = rng·random();
-    if(d*U >= (mu-K)*(mu-K)*(mu-K))
-        return K;
-stepP:
-    if(G < 0)
-        goto stepE;
-stepQ:
-    c = procf(mu, s, K, &px, &py, &fx, &fy);
-stepE:
-    E = rng·exponential(1.0);
-    U = rng·random();
-    U = U + U - 1;
-    T = 1.8 + copysign(E,U);
-    if(T < 0.6744)
-        goto stepE;
-    K = floor(mu + s*T);
-    c = procf(mu, s, K, &px, &py, &fx, &fy);
-stepH:
-    if(c*fabs(U) > (py*exp(px + E) - fy*exp(fx + E)))
-        goto stepE;
-    return K;
-}
-
-uint64
-rng·poisson(double mean)
-{
-    int64  n;
-    double z;
-
-    if(mean<10.0) {
-        for(n=0, z=rng·exponential(1.0); z<mean; ++n, z+=rng·exponential(1.0))
-            ;
-        return n;
-    }
-
-    return bigpoisson(mean);
-}
-- 
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