ESS_GUIESS_GUI_DocsESS_GUI_batch_fittingESS_GUI_bumps_abstractionESS_GUI_iss1116ESS_GUI_iss879ESS_GUI_iss959ESS_GUI_openclESS_GUI_orderingESS_GUI_sync_sascalccostrafo411magnetic_scattrelease-4.1.1release-4.1.2release-4.2.2release_4.0.1ticket-1009ticket-1094-headlessticket-1242-2d-resolutionticket-1243ticket-1249ticket885unittest-saveload
Last change
on this file since 2d52cf0 was
08648c0,
checked in by Jae Cho <jhjcho@…>, 13 years ago
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more s king's fractal models: todo: doc, test
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Property mode set to
100644
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File size:
1.6 KB
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1 | // by jcho |
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2 | #include <math.h> |
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3 | #include "libmultifunc/libfunc.h" |
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4 | #include <stdio.h> |
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5 | |
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6 | //used in Si func |
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7 | int factorial(int i) |
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8 | { |
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9 | int k, j; |
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10 | if (i<2){ |
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11 | return 1; |
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12 | } |
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13 | k=1; |
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14 | for(j=1;j<i;j++) |
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15 | { |
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16 | k=k*(j+1); |
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17 | } |
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18 | return k; |
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19 | } |
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20 | |
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21 | // Used in pearl nec model |
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22 | // Sine integral function: approximated within 1%!!! |
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23 | // integral of sin(x)/x up to namx term nmax=6 looks the best. |
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24 | double Si(double x) |
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25 | { |
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26 | int i; |
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27 | int nmax=6; |
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28 | double out; |
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29 | long double power; |
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30 | double pi = 4.0*atan(1.0); |
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31 | if (x >= pi*6.2/4.0){ |
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32 | |
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33 | double out_sin = 0.0; |
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34 | double out_cos = 0.0; |
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35 | out = pi/2.0; |
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36 | for (i=0; i<nmax-2; i+=1){ |
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37 | out_cos += pow(-1.0, i) * (double)factorial(2*i) / pow(x, 2*i+1); |
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38 | out_sin += pow(-1.0, i) * (double)factorial(2*i+1) / pow(x, 2*i+2); |
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39 | } |
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40 | out -= cos(x) * out_cos; |
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41 | out -= sin(x) * out_sin; |
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42 | return out; |
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43 | } |
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44 | out = 0.0; |
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45 | for (i=0; i<nmax; i+=1) |
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46 | { |
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47 | if (i==0){ |
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48 | out += x; |
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49 | continue; |
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50 | } |
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51 | power = pow(x,(2 * i + 1)); |
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52 | out += (double)pow(-1, i) * power / ((2.0 * (double)i + 1.0) * (double)factorial(2 * i + 1)); |
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53 | //printf ("Si=%g %g %d\n", x, out, i); |
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54 | } |
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55 | return out; |
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56 | } |
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57 | |
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58 | double sinc(double x) |
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59 | { |
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60 | if (x==0.0){ |
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61 | return 1.0; |
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62 | } |
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63 | return sin(x)/x; |
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64 | } |
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65 | |
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66 | double gamln(double xx) { |
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67 | |
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68 | double x,y,tmp,ser; |
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69 | static double cof[6]={76.18009172947146,-86.50532032941677, |
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70 | 24.01409824083091,-1.231739572450155, |
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71 | 0.1208650973866179e-2,-0.5395239384953e-5}; |
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72 | int j; |
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73 | |
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74 | y=x=xx; |
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75 | tmp=x+5.5; |
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76 | tmp -= (x+0.5)*log(tmp); |
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77 | ser=1.000000000190015; |
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78 | for (j=0;j<=5;j++) ser += cof[j]/++y; |
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79 | return -tmp+log(2.5066282746310005*ser/x); |
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80 | } |
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