| 1 |
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| 2 | using System;
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| 3 |
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| 4 | namespace alglib
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| 5 | {
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| 6 | public class nearunityunit
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| 7 | {
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| 8 | public static double log1p(double x)
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| 9 | {
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| 10 | double result = 0;
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| 11 | double z = 0;
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| 12 | double lp = 0;
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| 13 | double lq = 0;
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| 14 |
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| 15 | z = 1.0+x;
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| 16 | if( (double)(z)<(double)(0.70710678118654752440) | (double)(z)>(double)(1.41421356237309504880) )
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| 17 | {
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| 18 | result = Math.Log(z);
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| 19 | return result;
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| 20 | }
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| 21 | z = x*x;
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| 22 | lp = 4.5270000862445199635215E-5;
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| 23 | lp = lp*x+4.9854102823193375972212E-1;
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| 24 | lp = lp*x+6.5787325942061044846969E0;
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| 25 | lp = lp*x+2.9911919328553073277375E1;
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| 26 | lp = lp*x+6.0949667980987787057556E1;
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| 27 | lp = lp*x+5.7112963590585538103336E1;
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| 28 | lp = lp*x+2.0039553499201281259648E1;
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| 29 | lq = 1.0000000000000000000000E0;
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| 30 | lq = lq*x+1.5062909083469192043167E1;
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| 31 | lq = lq*x+8.3047565967967209469434E1;
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| 32 | lq = lq*x+2.2176239823732856465394E2;
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| 33 | lq = lq*x+3.0909872225312059774938E2;
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| 34 | lq = lq*x+2.1642788614495947685003E2;
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| 35 | lq = lq*x+6.0118660497603843919306E1;
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| 36 | z = -(0.5*z)+x*(z*lp/lq);
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| 37 | result = x+z;
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| 38 | return result;
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| 39 | }
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| 40 |
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| 41 |
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| 42 | public static double expm1(double x)
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| 43 | {
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| 44 | double result = 0;
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| 45 | double r = 0;
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| 46 | double xx = 0;
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| 47 | double ep = 0;
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| 48 | double eq = 0;
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| 49 |
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| 50 | if( (double)(x)<(double)(-0.5) | (double)(x)>(double)(0.5) )
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| 51 | {
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| 52 | result = Math.Exp(x)-1.0;
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| 53 | return result;
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| 54 | }
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| 55 | xx = x*x;
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| 56 | ep = 1.2617719307481059087798E-4;
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| 57 | ep = ep*xx+3.0299440770744196129956E-2;
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| 58 | ep = ep*xx+9.9999999999999999991025E-1;
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| 59 | eq = 3.0019850513866445504159E-6;
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| 60 | eq = eq*xx+2.5244834034968410419224E-3;
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| 61 | eq = eq*xx+2.2726554820815502876593E-1;
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| 62 | eq = eq*xx+2.0000000000000000000897E0;
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| 63 | r = x*ep;
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| 64 | r = r/(eq-r);
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| 65 | result = r+r;
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| 66 | return result;
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| 67 | }
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| 68 |
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| 69 |
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| 70 | public static double cosm1(double x)
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| 71 | {
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| 72 | double result = 0;
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| 73 | double xx = 0;
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| 74 | double c = 0;
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| 75 |
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| 76 | if( (double)(x)<(double)(-(0.25*Math.PI)) | (double)(x)>(double)(0.25*Math.PI) )
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| 77 | {
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| 78 | result = Math.Cos(x)-1;
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| 79 | return result;
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| 80 | }
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| 81 | xx = x*x;
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| 82 | c = 4.7377507964246204691685E-14;
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| 83 | c = c*xx-1.1470284843425359765671E-11;
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| 84 | c = c*xx+2.0876754287081521758361E-9;
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| 85 | c = c*xx-2.7557319214999787979814E-7;
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| 86 | c = c*xx+2.4801587301570552304991E-5;
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| 87 | c = c*xx-1.3888888888888872993737E-3;
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| 88 | c = c*xx+4.1666666666666666609054E-2;
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| 89 | result = -(0.5*xx)+xx*xx*c;
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| 90 | return result;
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| 91 | }
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| 92 | }
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| 93 | }
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