1 //2 // Copyright (c) 2003-2013 Scalable Informatics3 //4 5 6 7 var i,j,k,milestone,n,rc;8 var NMAX=5000000, MMAX=10;9 var array,total,p_sum,sum,delta_t,pi, pi_exact, t_now;10 var inf=0 ;11 var name_length=0;12 var cpu_name,c;13 var caliper = new Array(10);14 var mod_getopt = require('posix-getopt');15 var parser, option;16 var os = require("os");17 var printf = require("printf");18 var out;19 20 milestone = 0;21 n = 0;22 sum = 0.0;23 pi_exact = 4.0*Math.atan(1.0);24 25 caliper[milestone] = new Date().getTime();26 27 /*28 Riemann zeta function of integer argument29 (c.f. http://mathworld.wolfram.com/RiemannZetaFunction.html )30 31 zeta(n) = sum[k=1;k< =inf;k++] (1.0/pow(k,n))32 33 inf 34 ----35 \ 136 zeta(n) = > -37 / n38 ---- k39 k=140 41 42 this code will compute zeta(2) in order to calculate43 pi. pi*pi/6 = zeta(2), so pi = sqrt(6*zeta(2))44 45 to run this code, type46 47 ./rzf.exe -l INFINITY -n n48 49 where INFINITY is an integer value of how many terms you would 50 like to take for your sum, and n is the argument to the Reimann51 zeta function. If you use 2 for n, then it will calculate pi 52 for you as well.53 54 */55 var opt;56 parser = new mod_getopt.BasicParser('n:l:', process.argv);57 while ((opt = parser.getopt()) !== undefined) {58 switch (opt.option) {59 case 'n':60 console.log("n option found. Argument is: " + opt.optarg);61 n = opt.optarg;62 break;63 case 'l':64 console.log("l option found. Argument is: " + opt.optarg);65 inf = opt.optarg;66 break;67 }68 }69 70 71 72 sum=0;73 74 cpu_name = os.hostname();75 out = printf("D: running on machine = %s\n",cpu_name);76 console.log(out);77 78 milestone++;79 caliper[milestone] = (new Date).getTime();80 81 82 for(k=inf-1;k>=1;k--)83 {84 sum += 1.0/Math.pow(k,n);85 }86 87 milestone++;88 caliper[milestone] = new Date().getTime();89 90 out = printf("zeta(%i) = %.15f \n",n,sum);91 console.log(out);92 if (n == 2)93 {94 pi = Math.sqrt(sum*6.0);95 out = printf("pi = %.15f \n",pi);96 console.log(out);97 98 out = printf("error in pi = %.15f \n",pi_exact-pi);99 console.log(out);100 out = printf("relative error in pi = %.15f \n",(pi_exact-pi)/pi_exact);101 console.log(out);102 }103 104 105 /* now report the milestone time differences */106 for (i=0;i<=(milestone-1);i++)107 {108 delta_t = (caliper[i+1] -caliper[i])/1000;109 110 out = printf("Milestone %i to %i: time = %fs\n",i,i+1,delta_t);111 console.log(out);112 }Enlace
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