mirror of
https://github.com/LBRYFoundation/pool.git
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116 lines
No EOL
2.7 KiB
C
116 lines
No EOL
2.7 KiB
C
// Copyright (c) 2014 The a5a developers
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// Distributed under the MIT/X11 software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#include <stdio.h>
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#include <float.h>
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#include <limits.h>
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#include <math.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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//#include <gmpxx.h>
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#include "a5amath.h"
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//#define EPS1 (std::numeric_limits<double>::epsilon())
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#define EPS1 (DBL_EPSILON)
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#define EPS2 3.0e-11
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double exp_n(double xt)
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{
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double p1 = -700.0, p3 = -0.8e-8, p4 = 0.8e-8, p6 = 700.0;
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if(xt < p1)
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return 0;
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else if(xt > p6)
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return 1e200;
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else if(xt > p3 && xt < p4)
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return (1.0 + xt);
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else
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return exp(xt);
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}
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// 1 / (1 + exp(x1-x2))
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double exp_n2(double x1, double x2)
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{
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double p1 = -700., p2 = -37., p3 = -0.8e-8, p4 = 0.8e-8, p5 = 37., p6 = 700.;
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double xt = x1 - x2;
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if (xt < p1+1.e-200)
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return 1.;
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else if (xt > p1 && xt < p2 + 1.e-200)
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return ( 1. - exp(xt) );
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else if (xt > p2 && xt < p3 + 1.e-200)
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return ( 1. / (1. + exp(xt)) );
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else if (xt > p3 && xt < p4)
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return ( 1. / (2. + xt) );
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else if (xt > p4 - 1.e-200 && xt < p5)
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return ( exp(-xt) / (1. + exp(-xt)) );
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else if (xt > p5 - 1.e-200 && xt < p6)
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return ( exp(-xt) );
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else if (xt > p6 - 1.e-200)
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return 0.;
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}
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void gauleg(double x1, double x2, double x[], double w[], int n)
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{
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int m,j,i;
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double z1, z, xm, xl, pp, p3, p2, p1;
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m=(n+1)/2;
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xm=0.5*(x2+x1);
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xl=0.5*(x2-x1);
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for (i=1;i<=m;i++) {
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z=cos(3.141592654*(i-0.25)/(n+0.5));
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do {
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p1=1.0;
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p2=0.0;
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for (j=1;j<=n;j++) {
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p3=p2;
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p2=p1;
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p1=((2.0*j-1.0)*z*p2-(j-1.0)*p3)/j;
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}
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pp=n*(z*p1-p2)/(z*z-1.0);
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z1=z;
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z=z1-p1/pp;
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} while (fabs(z-z1) > EPS2);
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x[i]=xm-xl*z;
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x[n+1-i]=xm+xl*z;
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w[i]=2.0*xl/((1.0-z*z)*pp*pp);
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w[n+1-i]=w[i];
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}
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}
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double GaussianQuad_N(double func(const double), const double a2, const double b2, int NptGQ)
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{
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double s=0.0;
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double x[NptGQ], w[NptGQ];
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int j;
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// double dh=(b2-a2)/double(divs);
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gauleg(a2, b2, x, w, NptGQ);
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for (j=1; j<=NptGQ; j++) {
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s += w[j]*func(x[j]);
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}
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/*
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for (i=1; i<=divs; i++)
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{
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a0 = a2 + (i-1)*dh;
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b0 = a0 + dh;
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gauleg(a0, b0, x, w, NptGQ);
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for (j=1; j<=NptGQ; j++)
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{
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s += w[j]*func(x[j]);
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}
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}
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*/
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return s;
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}
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double swit_(double wvnmb)
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{
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return pow( (5.55243*(exp_n(-0.3*wvnmb/15.762) - exp_n(-0.6*wvnmb/15.762)))*wvnmb, 0.5)
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/ 1034.66 * pow(sin(wvnmb/65.), 2.);
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}
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uint32_t sw_(int nnounce, int divs)
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{
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double wmax = ((sqrt((double)(nnounce))*(1.+EPS1))/450+100);
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return ((uint32_t)(GaussianQuad_N(swit_, 0., wmax, divs)*(1.+EPS1)*1.e6));
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} |