• Home
  • Features
  • Pricing
  • Docs
  • Announcements
  • Sign In

openmc-dev / openmc / 15567165838

10 Jun 2025 06:18PM UTC coverage: 85.1% (-0.06%) from 85.158%
15567165838

Pull #3413

github

web-flow
Merge ec68c734c into f796fa04e
Pull Request #3413: More interpolation types in Tabular.

69 of 121 new or added lines in 3 files covered. (57.02%)

34 existing lines in 2 files now uncovered.

52396 of 61570 relevant lines covered (85.1%)

36584924.15 hits per line

Source File
Press 'n' to go to next uncovered line, 'b' for previous

97.23
/src/math_functions.cpp
1
#include "openmc/math_functions.h"
2

3
#include "openmc/external/Faddeeva.hh"
4
#include "openmc/external/LambertW.hpp"
5

6
#include "openmc/constants.h"
7
#include "openmc/random_lcg.h"
8

9
namespace openmc {
10

11
//==============================================================================
12
// Mathematical methods
13
//==============================================================================
14

15
double normal_percentile(double p)
168✔
16
{
17
  constexpr double p_low = 0.02425;
168✔
18
  constexpr double a[6] = {-3.969683028665376e1, 2.209460984245205e2,
19
    -2.759285104469687e2, 1.383577518672690e2, -3.066479806614716e1,
20
    2.506628277459239e0};
21
  constexpr double b[5] = {-5.447609879822406e1, 1.615858368580409e2,
22
    -1.556989798598866e2, 6.680131188771972e1, -1.328068155288572e1};
23
  constexpr double c[6] = {-7.784894002430293e-3, -3.223964580411365e-1,
24
    -2.400758277161838, -2.549732539343734, 4.374664141464968,
25
    2.938163982698783};
26
  constexpr double d[4] = {7.784695709041462e-3, 3.224671290700398e-1,
27
    2.445134137142996, 3.754408661907416};
28

29
  // The rational approximation used here is from an unpublished work at
30
  // http://home.online.no/~pjacklam/notes/invnorm/
31

32
  double z;
33
  double q;
34

35
  if (p < p_low) {
168✔
36
    // Rational approximation for lower region.
37

38
    q = std::sqrt(-2.0 * std::log(p));
11✔
39
    z = (((((c[0] * q + c[1]) * q + c[2]) * q + c[3]) * q + c[4]) * q + c[5]) /
11✔
40
        ((((d[0] * q + d[1]) * q + d[2]) * q + d[3]) * q + 1.0);
11✔
41

42
  } else if (p <= 1.0 - p_low) {
157✔
43
    // Rational approximation for central region
44
    q = p - 0.5;
146✔
45
    double r = q * q;
146✔
46
    z = (((((a[0] * r + a[1]) * r + a[2]) * r + a[3]) * r + a[4]) * r + a[5]) *
146✔
47
        q /
48
        (((((b[0] * r + b[1]) * r + b[2]) * r + b[3]) * r + b[4]) * r + 1.0);
146✔
49

50
  } else {
51
    // Rational approximation for upper region
52

53
    q = std::sqrt(-2.0 * std::log(1.0 - p));
11✔
54
    z = -(((((c[0] * q + c[1]) * q + c[2]) * q + c[3]) * q + c[4]) * q + c[5]) /
11✔
55
        ((((d[0] * q + d[1]) * q + d[2]) * q + d[3]) * q + 1.0);
11✔
56
  }
57

58
  // Refinement based on Newton's method
59

60
  z = z - (0.5 * std::erfc(-z / std::sqrt(2.0)) - p) * std::sqrt(2.0 * PI) *
168✔
61
            std::exp(0.5 * z * z);
168✔
62

63
  return z;
168✔
64
}
65

66
double t_percentile(double p, int df)
310✔
67
{
68
  double t;
69

70
  if (df == 1) {
310✔
71
    // For one degree of freedom, the t-distribution becomes a Cauchy
72
    // distribution whose cdf we can invert directly
73

74
    t = std::tan(PI * (p - 0.5));
71✔
75
  } else if (df == 2) {
239✔
76
    // For two degrees of freedom, the cdf is given by 1/2 + x/(2*sqrt(x^2 +
77
    // 2)). This can be directly inverted to yield the solution below
78

79
    t = 2.0 * std::sqrt(2.0) * (p - 0.5) /
71✔
80
        std::sqrt(1. - 4. * std::pow(p - 0.5, 2.));
71✔
81
  } else {
82
    // This approximation is from E. Olusegun George and Meenakshi Sivaram, "A
83
    // modification of the Fisher-Cornish approximation for the student t
84
    // percentiles," Communication in Statistics - Simulation and Computation,
85
    // 16 (4), pp. 1123-1132 (1987).
86
    double n = df;
168✔
87
    double k = 1. / (n - 2.);
168✔
88
    double z = normal_percentile(p);
168✔
89
    double z2 = z * z;
168✔
90
    t = std::sqrt(n * k) *
168✔
91
        (z + (z2 - 3.) * z * k / 4. +
168✔
92
          ((5. * z2 - 56.) * z2 + 75.) * z * k * k / 96. +
168✔
93
          (((z2 - 27.) * 3. * z2 + 417.) * z2 - 315.) * z * k * k * k / 384.);
168✔
94
  }
95

96
  return t;
310✔
97
}
98

99
void calc_pn_c(int n, double x, double pnx[])
187,239,121✔
100
{
101
  pnx[0] = 1.;
187,239,121✔
102
  if (n >= 1) {
187,239,121✔
103
    pnx[1] = x;
120,408,915✔
104
  }
105

106
  // Use recursion relation to build the higher orders
107
  for (int l = 1; l < n; l++) {
192,838,385✔
108
    pnx[l + 1] = ((2 * l + 1) * x * pnx[l] - l * pnx[l - 1]) / (l + 1);
5,599,264✔
109
  }
110
}
187,239,121✔
111

112
double evaluate_legendre(int n, const double data[], double x)
95,154,832✔
113
{
114
  double* pnx = new double[n + 1];
95,154,832✔
115
  double val = 0.0;
95,154,832✔
116
  calc_pn_c(n, x, pnx);
95,154,832✔
117
  for (int l = 0; l <= n; l++) {
239,494,217✔
118
    val += (l + 0.5) * data[l] * pnx[l];
144,339,385✔
119
  }
120
  delete[] pnx;
95,154,832✔
121
  return val;
95,154,832✔
122
}
123

124
void calc_rn_c(int n, const double uvw[3], double rn[])
11✔
125
{
126
  Direction u {uvw};
11✔
127
  calc_rn(n, u, rn);
11✔
128
}
11✔
129

130
void calc_rn(int n, Direction u, double rn[])
4,586,703✔
131
{
132
  // rn[] is assumed to have already been allocated to the correct size
133

134
  // Store the cosine of the polar angle and the azimuthal angle
135
  double w = u.z;
4,586,703✔
136
  double phi;
137
  if (u.x == 0.) {
4,586,703✔
138
    phi = 0.;
×
139
  } else {
140
    phi = std::atan2(u.y, u.x);
4,586,703✔
141
  }
142

143
  // Store the shorthand of 1-w * w
144
  double w2m1 = 1. - w * w;
4,586,703✔
145

146
  // Now evaluate the spherical harmonics function
147
  rn[0] = 1.;
4,586,703✔
148
  int i = 0;
4,586,703✔
149
  for (int l = 1; l <= n; l++) {
22,936,507✔
150
    // Set the index to the start of this order
151
    i += 2 * (l - 1) + 1;
18,349,804✔
152

153
    // Now evaluate each
154
    switch (l) {
18,349,804✔
155
    case 1:
4,586,703✔
156
      // l = 1, m = -1
157
      rn[i] = -(std::sqrt(w2m1) * std::sin(phi));
4,586,703✔
158
      // l = 1, m = 0
159
      rn[i + 1] = w;
4,586,703✔
160
      // l = 1, m = 1
161
      rn[i + 2] = -(std::sqrt(w2m1) * std::cos(phi));
4,586,703✔
162
      break;
4,586,703✔
163
    case 2:
4,586,703✔
164
      // l = 2, m = -2
165
      rn[i] = 0.288675134594813 * (-3. * w * w + 3.) * std::sin(2. * phi);
4,586,703✔
166
      // l = 2, m = -1
167
      rn[i + 1] = -(1.73205080756888 * w * std::sqrt(w2m1) * std::sin(phi));
4,586,703✔
168
      // l = 2, m = 0
169
      rn[i + 2] = 1.5 * w * w - 0.5;
4,586,703✔
170
      // l = 2, m = 1
171
      rn[i + 3] = -(1.73205080756888 * w * std::sqrt(w2m1) * std::cos(phi));
4,586,703✔
172
      // l = 2, m = 2
173
      rn[i + 4] = 0.288675134594813 * (-3. * w * w + 3.) * std::cos(2. * phi);
4,586,703✔
174
      break;
4,586,703✔
175
    case 3:
4,586,703✔
176
      // l = 3, m = -3
177
      rn[i] = -(0.790569415042095 * std::pow(w2m1, 1.5) * std::sin(3. * phi));
4,586,703✔
178
      // l = 3, m = -2
179
      rn[i + 1] = 1.93649167310371 * w * (w2m1)*std::sin(2. * phi);
4,586,703✔
180
      // l = 3, m = -1
181
      rn[i + 2] = -(0.408248290463863 * std::sqrt(w2m1) *
4,586,703✔
182
                    ((7.5) * w * w - 3. / 2.) * std::sin(phi));
4,586,703✔
183
      // l = 3, m = 0
184
      rn[i + 3] = 2.5 * std::pow(w, 3) - 1.5 * w;
4,586,703✔
185
      // l = 3, m = 1
186
      rn[i + 4] = -(0.408248290463863 * std::sqrt(w2m1) *
4,586,703✔
187
                    ((7.5) * w * w - 3. / 2.) * std::cos(phi));
4,586,703✔
188
      // l = 3, m = 2
189
      rn[i + 5] = 1.93649167310371 * w * (w2m1)*std::cos(2. * phi);
4,586,703✔
190
      // l = 3, m = 3
191
      rn[i + 6] =
4,586,703✔
192
        -(0.790569415042095 * std::pow(w2m1, 1.5) * std::cos(3. * phi));
4,586,703✔
193
      break;
4,586,703✔
194
    case 4:
4,586,703✔
195
      // l = 4, m = -4
196
      rn[i] = 0.739509972887452 * (w2m1 * w2m1) * std::sin(4.0 * phi);
4,586,703✔
197
      // l = 4, m = -3
198
      rn[i + 1] =
4,586,703✔
199
        -(2.09165006633519 * w * std::pow(w2m1, 1.5) * std::sin(3. * phi));
4,586,703✔
200
      // l = 4, m = -2
201
      rn[i + 2] =
4,586,703✔
202
        0.074535599249993 * (w2m1) * (52.5 * w * w - 7.5) * std::sin(2. * phi);
4,586,703✔
203
      // l = 4, m = -1
204
      rn[i + 3] = -(0.316227766016838 * std::sqrt(w2m1) *
9,173,406✔
205
                    (17.5 * std::pow(w, 3) - 7.5 * w) * std::sin(phi));
4,586,703✔
206
      // l = 4, m = 0
207
      rn[i + 4] = 4.375 * std::pow(w, 4) - 3.75 * w * w + 0.375;
4,586,703✔
208
      // l = 4, m = 1
209
      rn[i + 5] = -(0.316227766016838 * std::sqrt(w2m1) *
9,173,406✔
210
                    (17.5 * std::pow(w, 3) - 7.5 * w) * std::cos(phi));
4,586,703✔
211
      // l = 4, m = 2
212
      rn[i + 6] =
4,586,703✔
213
        0.074535599249993 * (w2m1) * (52.5 * w * w - 7.5) * std::cos(2. * phi);
4,586,703✔
214
      // l = 4, m = 3
215
      rn[i + 7] =
4,586,703✔
216
        -(2.09165006633519 * w * std::pow(w2m1, 1.5) * std::cos(3. * phi));
4,586,703✔
217
      // l = 4, m = 4
218
      rn[i + 8] = 0.739509972887452 * w2m1 * w2m1 * std::cos(4.0 * phi);
4,586,703✔
219
      break;
4,586,703✔
220
    case 5:
2,937✔
221
      // l = 5, m = -5
222
      rn[i] = -(0.701560760020114 * std::pow(w2m1, 2.5) * std::sin(5.0 * phi));
2,937✔
223
      // l = 5, m = -4
224
      rn[i + 1] = 2.21852991866236 * w * w2m1 * w2m1 * std::sin(4.0 * phi);
2,937✔
225
      // l = 5, m = -3
226
      rn[i + 2] = -(0.00996023841111995 * std::pow(w2m1, 1.5) *
2,937✔
227
                    ((945.0 / 2.) * w * w - 52.5) * std::sin(3. * phi));
2,937✔
228
      // l = 5, m = -2
229
      rn[i + 3] = 0.0487950036474267 * (w2m1) *
5,874✔
230
                  ((315.0 / 2.) * std::pow(w, 3) - 52.5 * w) *
2,937✔
231
                  std::sin(2. * phi);
2,937✔
232
      // l = 5, m = -1
233
      rn[i + 4] =
2,937✔
234
        -(0.258198889747161 * std::sqrt(w2m1) *
5,874✔
235
          (39.375 * std::pow(w, 4) - 105.0 / 4.0 * w * w + 15.0 / 8.0) *
2,937✔
236
          std::sin(phi));
2,937✔
237
      // l = 5, m = 0
238
      rn[i + 5] = 7.875 * std::pow(w, 5) - 8.75 * std::pow(w, 3) + 1.875 * w;
2,937✔
239
      // l = 5, m = 1
240
      rn[i + 6] =
2,937✔
241
        -(0.258198889747161 * std::sqrt(w2m1) *
5,874✔
242
          (39.375 * std::pow(w, 4) - 105.0 / 4.0 * w * w + 15.0 / 8.0) *
2,937✔
243
          std::cos(phi));
2,937✔
244
      // l = 5, m = 2
245
      rn[i + 7] = 0.0487950036474267 * (w2m1) *
5,874✔
246
                  ((315.0 / 2.) * std::pow(w, 3) - 52.5 * w) *
2,937✔
247
                  std::cos(2. * phi);
2,937✔
248
      // l = 5, m = 3
249
      rn[i + 8] = -(0.00996023841111995 * std::pow(w2m1, 1.5) *
2,937✔
250
                    ((945.0 / 2.) * w * w - 52.5) * std::cos(3. * phi));
2,937✔
251
      // l = 5, m = 4
252
      rn[i + 9] = 2.21852991866236 * w * w2m1 * w2m1 * std::cos(4.0 * phi);
2,937✔
253
      // l = 5, m = 5
254
      rn[i + 10] =
2,937✔
255
        -(0.701560760020114 * std::pow(w2m1, 2.5) * std::cos(5.0 * phi));
2,937✔
256
      break;
2,937✔
257
    case 6:
11✔
258
      // l = 6, m = -6
259
      rn[i] = 0.671693289381396 * std::pow(w2m1, 3) * std::sin(6.0 * phi);
11✔
260
      // l = 6, m = -5
261
      rn[i + 1] =
11✔
262
        -(2.32681380862329 * w * std::pow(w2m1, 2.5) * std::sin(5.0 * phi));
11✔
263
      // l = 6, m = -4
264
      rn[i + 2] = 0.00104990131391452 * w2m1 * w2m1 *
11✔
265
                  ((10395.0 / 2.) * w * w - 945.0 / 2.) * std::sin(4.0 * phi);
11✔
266
      // l = 6, m = -3
267
      rn[i + 3] = -(0.00575054632785295 * std::pow(w2m1, 1.5) *
22✔
268
                    ((3465.0 / 2.) * std::pow(w, 3) - 945.0 / 2. * w) *
11✔
269
                    std::sin(3. * phi));
11✔
270
      // l = 6, m = -2
271
      rn[i + 4] =
11✔
272
        0.0345032779671177 * (w2m1) *
22✔
273
        ((3465.0 / 8.0) * std::pow(w, 4) - 945.0 / 4.0 * w * w + 105.0 / 8.0) *
11✔
274
        std::sin(2. * phi);
11✔
275
      // l = 6, m = -1
276
      rn[i + 5] = -(0.218217890235992 * std::sqrt(w2m1) *
22✔
277
                    ((693.0 / 8.0) * std::pow(w, 5) -
11✔
278
                      315.0 / 4.0 * std::pow(w, 3) + (105.0 / 8.0) * w) *
11✔
279
                    std::sin(phi));
11✔
280
      // l = 6, m = 0
281
      rn[i + 6] = 14.4375 * std::pow(w, 6) - 19.6875 * std::pow(w, 4) +
11✔
282
                  6.5625 * w * w - 0.3125;
11✔
283
      // l = 6, m = 1
284
      rn[i + 7] = -(0.218217890235992 * std::sqrt(w2m1) *
22✔
285
                    ((693.0 / 8.0) * std::pow(w, 5) -
11✔
286
                      315.0 / 4.0 * std::pow(w, 3) + (105.0 / 8.0) * w) *
11✔
287
                    std::cos(phi));
11✔
288
      // l = 6, m = 2
289
      rn[i + 8] =
11✔
290
        0.0345032779671177 * w2m1 *
22✔
291
        ((3465.0 / 8.0) * std::pow(w, 4) - 945.0 / 4.0 * w * w + 105.0 / 8.0) *
11✔
292
        std::cos(2. * phi);
11✔
293
      // l = 6, m = 3
294
      rn[i + 9] = -(0.00575054632785295 * std::pow(w2m1, 1.5) *
22✔
295
                    ((3465.0 / 2.) * std::pow(w, 3) - 945.0 / 2. * w) *
11✔
296
                    std::cos(3. * phi));
11✔
297
      // l = 6, m = 4
298
      rn[i + 10] = 0.00104990131391452 * w2m1 * w2m1 *
11✔
299
                   ((10395.0 / 2.) * w * w - 945.0 / 2.) * std::cos(4.0 * phi);
11✔
300
      // l = 6, m = 5
301
      rn[i + 11] =
11✔
302
        -(2.32681380862329 * w * std::pow(w2m1, 2.5) * std::cos(5.0 * phi));
11✔
303
      // l = 6, m = 6
304
      rn[i + 12] = 0.671693289381396 * std::pow(w2m1, 3) * std::cos(6.0 * phi);
11✔
305
      break;
11✔
306
    case 7:
11✔
307
      // l = 7, m = -7
308
      rn[i] = -(0.647259849287749 * std::pow(w2m1, 3.5) * std::sin(7.0 * phi));
11✔
309
      // l = 7, m = -6
310
      rn[i + 1] =
11✔
311
        2.42182459624969 * w * std::pow(w2m1, 3) * std::sin(6.0 * phi);
11✔
312
      // l = 7, m = -5
313
      rn[i + 2] =
11✔
314
        -(9.13821798555235e-5 * std::pow(w2m1, 2.5) *
11✔
315
          ((135135.0 / 2.) * w * w - 10395.0 / 2.) * std::sin(5.0 * phi));
11✔
316
      // l = 7, m = -4
317
      rn[i + 3] = 0.000548293079133141 * w2m1 * w2m1 *
22✔
318
                  ((45045.0 / 2.) * std::pow(w, 3) - 10395.0 / 2. * w) *
11✔
319
                  std::sin(4.0 * phi);
11✔
320
      // l = 7, m = -3
321
      rn[i + 4] = -(0.00363696483726654 * std::pow(w2m1, 1.5) *
22✔
322
                    ((45045.0 / 8.0) * std::pow(w, 4) - 10395.0 / 4.0 * w * w +
11✔
323
                      945.0 / 8.0) *
11✔
324
                    std::sin(3. * phi));
11✔
325
      // l = 7, m = -2
326
      rn[i + 5] = 0.025717224993682 * (w2m1) *
22✔
327
                  ((9009.0 / 8.0) * std::pow(w, 5) -
11✔
328
                    3465.0 / 4.0 * std::pow(w, 3) + (945.0 / 8.0) * w) *
11✔
329
                  std::sin(2. * phi);
11✔
330
      // l = 7, m = -1
331
      rn[i + 6] =
11✔
332
        -(0.188982236504614 * std::sqrt(w2m1) *
22✔
333
          ((3003.0 / 16.0) * std::pow(w, 6) - 3465.0 / 16.0 * std::pow(w, 4) +
11✔
334
            (945.0 / 16.0) * w * w - 35.0 / 16.0) *
11✔
335
          std::sin(phi));
11✔
336
      // l = 7, m = 0
337
      rn[i + 7] = 26.8125 * std::pow(w, 7) - 43.3125 * std::pow(w, 5) +
11✔
338
                  19.6875 * std::pow(w, 3) - 2.1875 * w;
11✔
339
      // l = 7, m = 1
340
      rn[i + 8] =
11✔
341
        -(0.188982236504614 * std::sqrt(w2m1) *
22✔
342
          ((3003.0 / 16.0) * std::pow(w, 6) - 3465.0 / 16.0 * std::pow(w, 4) +
11✔
343
            (945.0 / 16.0) * w * w - 35.0 / 16.0) *
11✔
344
          std::cos(phi));
11✔
345
      // l = 7, m = 2
346
      rn[i + 9] = 0.025717224993682 * (w2m1) *
22✔
347
                  ((9009.0 / 8.0) * std::pow(w, 5) -
11✔
348
                    3465.0 / 4.0 * std::pow(w, 3) + (945.0 / 8.0) * w) *
11✔
349
                  std::cos(2. * phi);
11✔
350
      // l = 7, m = 3
351
      rn[i + 10] = -(0.00363696483726654 * std::pow(w2m1, 1.5) *
22✔
352
                     ((45045.0 / 8.0) * std::pow(w, 4) - 10395.0 / 4.0 * w * w +
11✔
353
                       945.0 / 8.0) *
11✔
354
                     std::cos(3. * phi));
11✔
355
      // l = 7, m = 4
356
      rn[i + 11] = 0.000548293079133141 * w2m1 * w2m1 *
22✔
357
                   ((45045.0 / 2.) * std::pow(w, 3) - 10395.0 / 2. * w) *
11✔
358
                   std::cos(4.0 * phi);
11✔
359
      // l = 7, m = 5
360
      rn[i + 12] =
11✔
361
        -(9.13821798555235e-5 * std::pow(w2m1, 2.5) *
11✔
362
          ((135135.0 / 2.) * w * w - 10395.0 / 2.) * std::cos(5.0 * phi));
11✔
363
      // l = 7, m = 6
364
      rn[i + 13] =
11✔
365
        2.42182459624969 * w * std::pow(w2m1, 3) * std::cos(6.0 * phi);
11✔
366
      // l = 7, m = 7
367
      rn[i + 14] =
11✔
368
        -(0.647259849287749 * std::pow(w2m1, 3.5) * std::cos(7.0 * phi));
11✔
369
      break;
11✔
370
    case 8:
11✔
371
      // l = 8, m = -8
372
      rn[i] = 0.626706654240044 * std::pow(w2m1, 4) * std::sin(8.0 * phi);
11✔
373
      // l = 8, m = -7
374
      rn[i + 1] =
11✔
375
        -(2.50682661696018 * w * std::pow(w2m1, 3.5) * std::sin(7.0 * phi));
11✔
376
      // l = 8, m = -6
377
      rn[i + 2] = 6.77369783729086e-6 * std::pow(w2m1, 3) *
11✔
378
                  ((2027025.0 / 2.) * w * w - 135135.0 / 2.) *
11✔
379
                  std::sin(6.0 * phi);
11✔
380
      // l = 8, m = -5
381
      rn[i + 3] = -(4.38985792528482e-5 * std::pow(w2m1, 2.5) *
22✔
382
                    ((675675.0 / 2.) * std::pow(w, 3) - 135135.0 / 2. * w) *
11✔
383
                    std::sin(5.0 * phi));
11✔
384
      // l = 8, m = -4
385
      rn[i + 4] = 0.000316557156832328 * w2m1 * w2m1 *
22✔
386
                  ((675675.0 / 8.0) * std::pow(w, 4) - 135135.0 / 4.0 * w * w +
11✔
387
                    10395.0 / 8.0) *
11✔
388
                  std::sin(4.0 * phi);
11✔
389
      // l = 8, m = -3
390
      rn[i + 5] = -(0.00245204119306875 * std::pow(w2m1, 1.5) *
22✔
391
                    ((135135.0 / 8.0) * std::pow(w, 5) -
11✔
392
                      45045.0 / 4.0 * std::pow(w, 3) + (10395.0 / 8.0) * w) *
11✔
393
                    std::sin(3. * phi));
11✔
394
      // l = 8, m = -2
395
      rn[i + 6] =
11✔
396
        0.0199204768222399 * (w2m1) *
22✔
397
        ((45045.0 / 16.0) * std::pow(w, 6) - 45045.0 / 16.0 * std::pow(w, 4) +
11✔
398
          (10395.0 / 16.0) * w * w - 315.0 / 16.0) *
11✔
399
        std::sin(2. * phi);
11✔
400
      // l = 8, m = -1
401
      rn[i + 7] =
11✔
402
        -(0.166666666666667 * std::sqrt(w2m1) *
22✔
403
          ((6435.0 / 16.0) * std::pow(w, 7) - 9009.0 / 16.0 * std::pow(w, 5) +
11✔
404
            (3465.0 / 16.0) * std::pow(w, 3) - 315.0 / 16.0 * w) *
11✔
405
          std::sin(phi));
11✔
406
      // l = 8, m = 0
407
      rn[i + 8] = 50.2734375 * std::pow(w, 8) - 93.84375 * std::pow(w, 6) +
11✔
408
                  54.140625 * std::pow(w, 4) - 9.84375 * w * w + 0.2734375;
11✔
409
      // l = 8, m = 1
410
      rn[i + 9] =
11✔
411
        -(0.166666666666667 * std::sqrt(w2m1) *
22✔
412
          ((6435.0 / 16.0) * std::pow(w, 7) - 9009.0 / 16.0 * std::pow(w, 5) +
11✔
413
            (3465.0 / 16.0) * std::pow(w, 3) - 315.0 / 16.0 * w) *
11✔
414
          std::cos(phi));
11✔
415
      // l = 8, m = 2
416
      rn[i + 10] =
11✔
417
        0.0199204768222399 * (w2m1) *
22✔
418
        ((45045.0 / 16.0) * std::pow(w, 6) - 45045.0 / 16.0 * std::pow(w, 4) +
11✔
419
          (10395.0 / 16.0) * w * w - 315.0 / 16.0) *
11✔
420
        std::cos(2. * phi);
11✔
421
      // l = 8, m = 3
422
      rn[i + 11] = -(0.00245204119306875 * std::pow(w2m1, 1.5) *
22✔
423
                     ((135135.0 / 8.0) * std::pow(w, 5) -
11✔
424
                       45045.0 / 4.0 * std::pow(w, 3) + (10395.0 / 8.0) * w) *
11✔
425
                     std::cos(3. * phi));
11✔
426
      // l = 8, m = 4
427
      rn[i + 12] = 0.000316557156832328 * w2m1 * w2m1 *
22✔
428
                   ((675675.0 / 8.0) * std::pow(w, 4) - 135135.0 / 4.0 * w * w +
11✔
429
                     10395.0 / 8.0) *
11✔
430
                   std::cos(4.0 * phi);
11✔
431
      // l = 8, m = 5
432
      rn[i + 13] = -(4.38985792528482e-5 * std::pow(w2m1, 2.5) *
22✔
433
                     ((675675.0 / 2.) * std::pow(w, 3) - 135135.0 / 2. * w) *
11✔
434
                     std::cos(5.0 * phi));
11✔
435
      // l = 8, m = 6
436
      rn[i + 14] = 6.77369783729086e-6 * std::pow(w2m1, 3) *
11✔
437
                   ((2027025.0 / 2.) * w * w - 135135.0 / 2.) *
11✔
438
                   std::cos(6.0 * phi);
11✔
439
      // l = 8, m = 7
440
      rn[i + 15] =
11✔
441
        -(2.50682661696018 * w * std::pow(w2m1, 3.5) * std::cos(7.0 * phi));
11✔
442
      // l = 8, m = 8
443
      rn[i + 16] = 0.626706654240044 * std::pow(w2m1, 4) * std::cos(8.0 * phi);
11✔
444
      break;
11✔
445
    case 9:
11✔
446
      // l = 9, m = -9
447
      rn[i] = -(0.609049392175524 * std::pow(w2m1, 4.5) * std::sin(9.0 * phi));
11✔
448
      // l = 9, m = -8
449
      rn[i + 1] =
11✔
450
        2.58397773170915 * w * std::pow(w2m1, 4) * std::sin(8.0 * phi);
11✔
451
      // l = 9, m = -7
452
      rn[i + 2] =
11✔
453
        -(4.37240315267812e-7 * std::pow(w2m1, 3.5) *
11✔
454
          ((34459425.0 / 2.) * w * w - 2027025.0 / 2.) * std::sin(7.0 * phi));
11✔
455
      // l = 9, m = -6
456
      rn[i + 3] = 3.02928976464514e-6 * std::pow(w2m1, 3) *
11✔
457
                  ((11486475.0 / 2.) * std::pow(w, 3) - 2027025.0 / 2. * w) *
11✔
458
                  std::sin(6.0 * phi);
11✔
459
      // l = 9, m = -5
460
      rn[i + 4] = -(2.34647776186144e-5 * std::pow(w2m1, 2.5) *
22✔
461
                    ((11486475.0 / 8.0) * std::pow(w, 4) -
11✔
462
                      2027025.0 / 4.0 * w * w + 135135.0 / 8.0) *
11✔
463
                    std::sin(5.0 * phi));
11✔
464
      // l = 9, m = -4
465
      rn[i + 5] = 0.000196320414650061 * w2m1 * w2m1 *
22✔
466
                  ((2297295.0 / 8.0) * std::pow(w, 5) -
11✔
467
                    675675.0 / 4.0 * std::pow(w, 3) + (135135.0 / 8.0) * w) *
11✔
468
                  std::sin(4.0 * phi);
11✔
469
      // l = 9, m = -3
470
      rn[i + 6] = -(
11✔
471
        0.00173385495536766 * std::pow(w2m1, 1.5) *
22✔
472
        ((765765.0 / 16.0) * std::pow(w, 6) - 675675.0 / 16.0 * std::pow(w, 4) +
11✔
473
          (135135.0 / 16.0) * w * w - 3465.0 / 16.0) *
11✔
474
        std::sin(3. * phi));
11✔
475
      // l = 9, m = -2
476
      rn[i + 7] =
11✔
477
        0.0158910431540932 * (w2m1) *
22✔
478
        ((109395.0 / 16.0) * std::pow(w, 7) - 135135.0 / 16.0 * std::pow(w, 5) +
11✔
479
          (45045.0 / 16.0) * std::pow(w, 3) - 3465.0 / 16.0 * w) *
11✔
480
        std::sin(2. * phi);
11✔
481
      // l = 9, m = -1
482
      rn[i + 8] = -(
11✔
483
        0.149071198499986 * std::sqrt(w2m1) *
22✔
484
        ((109395.0 / 128.0) * std::pow(w, 8) - 45045.0 / 32.0 * std::pow(w, 6) +
11✔
485
          (45045.0 / 64.0) * std::pow(w, 4) - 3465.0 / 32.0 * w * w +
11✔
486
          315.0 / 128.0) *
11✔
487
        std::sin(phi));
11✔
488
      // l = 9, m = 0
489
      rn[i + 9] = 94.9609375 * std::pow(w, 9) - 201.09375 * std::pow(w, 7) +
11✔
490
                  140.765625 * std::pow(w, 5) - 36.09375 * std::pow(w, 3) +
11✔
491
                  2.4609375 * w;
11✔
492
      // l = 9, m = 1
493
      rn[i + 10] = -(
11✔
494
        0.149071198499986 * std::sqrt(w2m1) *
22✔
495
        ((109395.0 / 128.0) * std::pow(w, 8) - 45045.0 / 32.0 * std::pow(w, 6) +
11✔
496
          (45045.0 / 64.0) * std::pow(w, 4) - 3465.0 / 32.0 * w * w +
11✔
497
          315.0 / 128.0) *
11✔
498
        std::cos(phi));
11✔
499
      // l = 9, m = 2
500
      rn[i + 11] =
11✔
501
        0.0158910431540932 * (w2m1) *
22✔
502
        ((109395.0 / 16.0) * std::pow(w, 7) - 135135.0 / 16.0 * std::pow(w, 5) +
11✔
503
          (45045.0 / 16.0) * std::pow(w, 3) - 3465.0 / 16.0 * w) *
11✔
504
        std::cos(2. * phi);
11✔
505
      // l = 9, m = 3
506
      rn[i + 12] = -(
11✔
507
        0.00173385495536766 * std::pow(w2m1, 1.5) *
22✔
508
        ((765765.0 / 16.0) * std::pow(w, 6) - 675675.0 / 16.0 * std::pow(w, 4) +
11✔
509
          (135135.0 / 16.0) * w * w - 3465.0 / 16.0) *
11✔
510
        std::cos(3. * phi));
11✔
511
      // l = 9, m = 4
512
      rn[i + 13] = 0.000196320414650061 * w2m1 * w2m1 *
22✔
513
                   ((2297295.0 / 8.0) * std::pow(w, 5) -
11✔
514
                     675675.0 / 4.0 * std::pow(w, 3) + (135135.0 / 8.0) * w) *
11✔
515
                   std::cos(4.0 * phi);
11✔
516
      // l = 9, m = 5
517
      rn[i + 14] = -(2.34647776186144e-5 * std::pow(w2m1, 2.5) *
22✔
518
                     ((11486475.0 / 8.0) * std::pow(w, 4) -
11✔
519
                       2027025.0 / 4.0 * w * w + 135135.0 / 8.0) *
11✔
520
                     std::cos(5.0 * phi));
11✔
521
      // l = 9, m = 6
522
      rn[i + 15] = 3.02928976464514e-6 * std::pow(w2m1, 3) *
11✔
523
                   ((11486475.0 / 2.) * std::pow(w, 3) - 2027025.0 / 2. * w) *
11✔
524
                   std::cos(6.0 * phi);
11✔
525
      // l = 9, m = 7
526
      rn[i + 16] =
11✔
527
        -(4.37240315267812e-7 * std::pow(w2m1, 3.5) *
11✔
528
          ((34459425.0 / 2.) * w * w - 2027025.0 / 2.) * std::cos(7.0 * phi));
11✔
529
      // l = 9, m = 8
530
      rn[i + 17] =
11✔
531
        2.58397773170915 * w * std::pow(w2m1, 4) * std::cos(8.0 * phi);
11✔
532
      // l = 9, m = 9
533
      rn[i + 18] =
11✔
534
        -(0.609049392175524 * std::pow(w2m1, 4.5) * std::cos(9.0 * phi));
11✔
535
      break;
11✔
536
    case 10:
11✔
537
      // l = 10, m = -10
538
      rn[i] = 0.593627917136573 * std::pow(w2m1, 5) * std::sin(10.0 * phi);
11✔
539
      // l = 10, m = -9
540
      rn[i + 1] =
11✔
541
        -(2.65478475211798 * w * std::pow(w2m1, 4.5) * std::sin(9.0 * phi));
11✔
542
      // l = 10, m = -8
543
      rn[i + 2] = 2.49953651452314e-8 * std::pow(w2m1, 4) *
11✔
544
                  ((654729075.0 / 2.) * w * w - 34459425.0 / 2.) *
11✔
545
                  std::sin(8.0 * phi);
11✔
546
      // l = 10, m = -7
547
      rn[i + 3] =
11✔
548
        -(1.83677671621093e-7 * std::pow(w2m1, 3.5) *
22✔
549
          ((218243025.0 / 2.) * std::pow(w, 3) - 34459425.0 / 2. * w) *
11✔
550
          std::sin(7.0 * phi));
11✔
551
      // l = 10, m = -6
552
      rn[i + 4] = 1.51464488232257e-6 * std::pow(w2m1, 3) *
11✔
553
                  ((218243025.0 / 8.0) * std::pow(w, 4) -
11✔
554
                    34459425.0 / 4.0 * w * w + 2027025.0 / 8.0) *
11✔
555
                  std::sin(6.0 * phi);
11✔
556
      // l = 10, m = -5
557
      rn[i + 5] =
11✔
558
        -(1.35473956745817e-5 * std::pow(w2m1, 2.5) *
22✔
559
          ((43648605.0 / 8.0) * std::pow(w, 5) -
11✔
560
            11486475.0 / 4.0 * std::pow(w, 3) + (2027025.0 / 8.0) * w) *
11✔
561
          std::sin(5.0 * phi));
11✔
562
      // l = 10, m = -4
563
      rn[i + 6] = 0.000128521880085575 * w2m1 * w2m1 *
22✔
564
                  ((14549535.0 / 16.0) * std::pow(w, 6) -
11✔
565
                    11486475.0 / 16.0 * std::pow(w, 4) +
11✔
566
                    (2027025.0 / 16.0) * w * w - 45045.0 / 16.0) *
11✔
567
                  std::sin(4.0 * phi);
11✔
568
      // l = 10, m = -3
569
      rn[i + 7] = -(0.00127230170115096 * std::pow(w2m1, 1.5) *
22✔
570
                    ((2078505.0 / 16.0) * std::pow(w, 7) -
11✔
571
                      2297295.0 / 16.0 * std::pow(w, 5) +
11✔
572
                      (675675.0 / 16.0) * std::pow(w, 3) - 45045.0 / 16.0 * w) *
11✔
573
                    std::sin(3. * phi));
11✔
574
      // l = 10, m = -2
575
      rn[i + 8] = 0.012974982402692 * (w2m1) *
22✔
576
                  ((2078505.0 / 128.0) * std::pow(w, 8) -
11✔
577
                    765765.0 / 32.0 * std::pow(w, 6) +
11✔
578
                    (675675.0 / 64.0) * std::pow(w, 4) -
11✔
579
                    45045.0 / 32.0 * w * w + 3465.0 / 128.0) *
11✔
580
                  std::sin(2. * phi);
11✔
581
      // l = 10, m = -1
582
      rn[i + 9] = -(0.134839972492648 * std::sqrt(w2m1) *
22✔
583
                    ((230945.0 / 128.0) * std::pow(w, 9) -
11✔
584
                      109395.0 / 32.0 * std::pow(w, 7) +
11✔
585
                      (135135.0 / 64.0) * std::pow(w, 5) -
11✔
586
                      15015.0 / 32.0 * std::pow(w, 3) + (3465.0 / 128.0) * w) *
11✔
587
                    std::sin(phi));
11✔
588
      // l = 10, m = 0
589
      rn[i + 10] = 180.42578125 * std::pow(w, 10) -
11✔
590
                   427.32421875 * std::pow(w, 8) +
11✔
591
                   351.9140625 * std::pow(w, 6) - 117.3046875 * std::pow(w, 4) +
11✔
592
                   13.53515625 * w * w - 0.24609375;
11✔
593
      // l = 10, m = 1
594
      rn[i + 11] = -(0.134839972492648 * std::sqrt(w2m1) *
22✔
595
                     ((230945.0 / 128.0) * std::pow(w, 9) -
11✔
596
                       109395.0 / 32.0 * std::pow(w, 7) +
11✔
597
                       (135135.0 / 64.0) * std::pow(w, 5) -
11✔
598
                       15015.0 / 32.0 * std::pow(w, 3) + (3465.0 / 128.0) * w) *
11✔
599
                     std::cos(phi));
11✔
600
      // l = 10, m = 2
601
      rn[i + 12] = 0.012974982402692 * (w2m1) *
22✔
602
                   ((2078505.0 / 128.0) * std::pow(w, 8) -
11✔
603
                     765765.0 / 32.0 * std::pow(w, 6) +
11✔
604
                     (675675.0 / 64.0) * std::pow(w, 4) -
11✔
605
                     45045.0 / 32.0 * w * w + 3465.0 / 128.0) *
11✔
606
                   std::cos(2. * phi);
11✔
607
      // l = 10, m = 3
608
      rn[i + 13] =
11✔
609
        -(0.00127230170115096 * std::pow(w2m1, 1.5) *
22✔
610
          ((2078505.0 / 16.0) * std::pow(w, 7) -
11✔
611
            2297295.0 / 16.0 * std::pow(w, 5) +
11✔
612
            (675675.0 / 16.0) * std::pow(w, 3) - 45045.0 / 16.0 * w) *
11✔
613
          std::cos(3. * phi));
11✔
614
      // l = 10, m = 4
615
      rn[i + 14] = 0.000128521880085575 * w2m1 * w2m1 *
22✔
616
                   ((14549535.0 / 16.0) * std::pow(w, 6) -
11✔
617
                     11486475.0 / 16.0 * std::pow(w, 4) +
11✔
618
                     (2027025.0 / 16.0) * w * w - 45045.0 / 16.0) *
11✔
619
                   std::cos(4.0 * phi);
11✔
620
      // l = 10, m = 5
621
      rn[i + 15] =
11✔
622
        -(1.35473956745817e-5 * std::pow(w2m1, 2.5) *
22✔
623
          ((43648605.0 / 8.0) * std::pow(w, 5) -
11✔
624
            11486475.0 / 4.0 * std::pow(w, 3) + (2027025.0 / 8.0) * w) *
11✔
625
          std::cos(5.0 * phi));
11✔
626
      // l = 10, m = 6
627
      rn[i + 16] = 1.51464488232257e-6 * std::pow(w2m1, 3) *
11✔
628
                   ((218243025.0 / 8.0) * std::pow(w, 4) -
11✔
629
                     34459425.0 / 4.0 * w * w + 2027025.0 / 8.0) *
11✔
630
                   std::cos(6.0 * phi);
11✔
631
      // l = 10, m = 7
632
      rn[i + 17] =
11✔
633
        -(1.83677671621093e-7 * std::pow(w2m1, 3.5) *
22✔
634
          ((218243025.0 / 2.) * std::pow(w, 3) - 34459425.0 / 2. * w) *
11✔
635
          std::cos(7.0 * phi));
11✔
636
      // l = 10, m = 8
637
      rn[i + 18] = 2.49953651452314e-8 * std::pow(w2m1, 4) *
11✔
638
                   ((654729075.0 / 2.) * w * w - 34459425.0 / 2.) *
11✔
639
                   std::cos(8.0 * phi);
11✔
640
      // l = 10, m = 9
641
      rn[i + 19] =
11✔
642
        -(2.65478475211798 * w * std::pow(w2m1, 4.5) * std::cos(9.0 * phi));
11✔
643
      // l = 10, m = 10
644
      rn[i + 20] = 0.593627917136573 * std::pow(w2m1, 5) * std::cos(10.0 * phi);
11✔
645
    }
646
  }
647
}
4,586,703✔
648

649
void calc_zn(int n, double rho, double phi, double zn[])
2,734,853✔
650
{
651
  // ===========================================================================
652
  // Determine vector of sin(n*phi) and cos(n*phi). This takes advantage of the
653
  // following recurrence relations so that only a single sin/cos have to be
654
  // evaluated (https://mathworld.wolfram.com/Multiple-AngleFormulas.html)
655
  //
656
  // sin(nx) = 2 cos(x) sin((n-1)x) - sin((n-2)x)
657
  // cos(nx) = 2 cos(x) cos((n-1)x) - cos((n-2)x)
658

659
  double sin_phi = std::sin(phi);
2,734,853✔
660
  double cos_phi = std::cos(phi);
2,734,853✔
661

662
  vector<double> sin_phi_vec(n + 1); // Sin[n * phi]
2,734,853✔
663
  vector<double> cos_phi_vec(n + 1); // Cos[n * phi]
2,734,853✔
664
  sin_phi_vec[0] = 1.0;
2,734,853✔
665
  cos_phi_vec[0] = 1.0;
2,734,853✔
666
  sin_phi_vec[1] = 2.0 * cos_phi;
2,734,853✔
667
  cos_phi_vec[1] = cos_phi;
2,734,853✔
668

669
  for (int i = 2; i <= n; i++) {
13,671,196✔
670
    sin_phi_vec[i] = 2. * cos_phi * sin_phi_vec[i - 1] - sin_phi_vec[i - 2];
10,936,343✔
671
    cos_phi_vec[i] = 2. * cos_phi * cos_phi_vec[i - 1] - cos_phi_vec[i - 2];
10,936,343✔
672
  }
673

674
  for (int i = 0; i <= n; i++) {
19,140,902✔
675
    sin_phi_vec[i] *= sin_phi;
16,406,049✔
676
  }
677

678
  // ===========================================================================
679
  // Calculate R_pq(rho)
680
  // Matrix forms of the coefficients which are easier to work with
681
  vector<vector<double>> zn_mat(n + 1, vector<double>(n + 1));
5,469,706✔
682

683
  // Fill the main diagonal first (Eq 3.9 in Chong)
684
  for (int p = 0; p <= n; p++) {
19,140,902✔
685
    zn_mat[p][p] = std::pow(rho, p);
16,406,049✔
686
  }
687

688
  // Fill the 2nd diagonal (Eq 3.10 in Chong)
689
  for (int q = 0; q <= n - 2; q++) {
13,671,196✔
690
    zn_mat[q][q + 2] = (q + 2) * zn_mat[q + 2][q + 2] - (q + 1) * zn_mat[q][q];
10,936,343✔
691
  }
692

693
  // Fill in the rest of the values using the original results (Eq. 3.8 in
694
  // Chong)
695
  for (int p = 4; p <= n; p++) {
8,201,490✔
696
    double k2 = 2 * p * (p - 1) * (p - 2);
5,466,637✔
697
    for (int q = p - 4; q >= 0; q -= 2) {
10,933,373✔
698
      double k1 = ((p + q) * (p - q) * (p - 2)) / 2.;
5,466,736✔
699
      double k3 = -q * q * (p - 1) - p * (p - 1) * (p - 2);
5,466,736✔
700
      double k4 = (-p * (p + q - 2) * (p - q - 2)) / 2.;
5,466,736✔
701
      zn_mat[q][p] =
5,466,736✔
702
        ((k2 * rho * rho + k3) * zn_mat[q][p - 2] + k4 * zn_mat[q][p - 4]) / k1;
5,466,736✔
703
    }
704
  }
705

706
  // Roll into a single vector for easier computation later
707
  // The vector is ordered (0,0), (1,-1), (1,1), (2,-2), (2,0),
708
  // (2, 2), ....   in (n,m) indices
709
  // Note that the cos and sin vectors are offset by one
710
  // sin_phi_vec = [sin(x), sin(2x), sin(3x) ...]
711
  // cos_phi_vec = [1.0, cos(x), cos(2x)... ]
712
  int i = 0;
2,734,853✔
713
  for (int p = 0; p <= n; p++) {
19,140,902✔
714
    for (int q = -p; q <= p; q += 2) {
73,821,176✔
715
      if (q < 0) {
57,415,127✔
716
        zn[i] = zn_mat[std::abs(q)][p] * sin_phi_vec[std::abs(q) - 1];
24,605,999✔
717
      } else if (q == 0) {
32,809,128✔
718
        zn[i] = zn_mat[q][p];
8,203,129✔
719
      } else {
720
        zn[i] = zn_mat[q][p] * cos_phi_vec[q];
24,605,999✔
721
      }
722
      i++;
57,415,127✔
723
    }
724
  }
725
}
2,734,853✔
726

727
void calc_zn_rad(int n, double rho, double zn_rad[])
44✔
728
{
729
  // Calculate R_p0(rho) as Zn_p0(rho)
730
  // Set up the array of the coefficients
731

732
  double q = 0;
44✔
733

734
  // R_00 is always 1
735
  zn_rad[0] = 1;
44✔
736

737
  // Fill in the rest of the array (Eq 3.8 and Eq 3.10 in Chong)
738
  for (int p = 2; p <= n; p += 2) {
264✔
739
    int index = int(p / 2);
220✔
740
    if (p == 2) {
220✔
741
      // Setting up R_22 to calculate R_20 (Eq 3.10 in Chong)
742
      double R_22 = rho * rho;
44✔
743
      zn_rad[index] = 2 * R_22 - zn_rad[0];
44✔
744
    } else {
745
      double k1 = ((p + q) * (p - q) * (p - 2)) / 2.;
176✔
746
      double k2 = 2 * p * (p - 1) * (p - 2);
176✔
747
      double k3 = -q * q * (p - 1) - p * (p - 1) * (p - 2);
176✔
748
      double k4 = (-p * (p + q - 2) * (p - q - 2)) / 2.;
176✔
749
      zn_rad[index] =
176✔
750
        ((k2 * rho * rho + k3) * zn_rad[index - 1] + k4 * zn_rad[index - 2]) /
176✔
751
        k1;
752
    }
753
  }
754
}
44✔
755

756
void rotate_angle_c(double uvw[3], double mu, const double* phi, uint64_t* seed)
33✔
757
{
758
  Direction u = rotate_angle({uvw}, mu, phi, seed);
33✔
759
  uvw[0] = u.x;
33✔
760
  uvw[1] = u.y;
33✔
761
  uvw[2] = u.z;
33✔
762
}
33✔
763

764
Direction rotate_angle(
2,147,483,647✔
765
  Direction u, double mu, const double* phi, uint64_t* seed)
766
{
767
  // Sample azimuthal angle in [0,2pi) if none provided
768
  double phi_;
769
  if (phi != nullptr) {
2,147,483,647✔
770
    phi_ = (*phi);
16,540,062✔
771
  } else {
772
    phi_ = 2.0 * PI * prn(seed);
2,147,483,647✔
773
  }
774

775
  // Precompute factors to save flops
776
  double sinphi = std::sin(phi_);
2,147,483,647✔
777
  double cosphi = std::cos(phi_);
2,147,483,647✔
778
  double a = std::sqrt(std::fmax(0., 1. - mu * mu));
2,147,483,647✔
779
  double b = std::sqrt(std::fmax(0., 1. - u.z * u.z));
2,147,483,647✔
780

781
  // Need to treat special case where sqrt(1 - w**2) is close to zero by
782
  // expanding about the v component rather than the w component
783
  if (b > 1e-10) {
2,147,483,647✔
784
    return {mu * u.x + a * (u.x * u.z * cosphi - u.y * sinphi) / b,
2,147,483,647✔
785
      mu * u.y + a * (u.y * u.z * cosphi + u.x * sinphi) / b,
2,147,483,647✔
786
      mu * u.z - a * b * cosphi};
2,147,483,647✔
787
  } else {
788
    b = std::sqrt(1. - u.y * u.y);
417,648✔
789
    return {mu * u.x + a * (-u.x * u.y * sinphi + u.z * cosphi) / b,
417,648✔
790
      mu * u.y + a * b * sinphi,
417,648✔
791
      mu * u.z - a * (u.y * u.z * sinphi + u.x * cosphi) / b};
417,648✔
792
  }
793
}
794

795
void spline(int n, const double x[], const double y[], double z[])
102,278✔
796
{
797
  vector<double> c_new(n - 1);
102,278✔
798

799
  // Set natural boundary conditions
800
  c_new[0] = 0.0;
102,278✔
801
  z[0] = 0.0;
102,278✔
802
  z[n - 1] = 0.0;
102,278✔
803

804
  // Solve using tridiagonal matrix algorithm; first do forward sweep
805
  for (int i = 1; i < n - 1; i++) {
10,252,484✔
806
    double a = x[i] - x[i - 1];
10,150,206✔
807
    double c = x[i + 1] - x[i];
10,150,206✔
808
    double b = 2.0 * (a + c);
10,150,206✔
809
    double d = 6.0 * ((y[i + 1] - y[i]) / c - (y[i] - y[i - 1]) / a);
10,150,206✔
810

811
    c_new[i] = c / (b - a * c_new[i - 1]);
10,150,206✔
812
    z[i] = (d - a * z[i - 1]) / (b - a * c_new[i - 1]);
10,150,206✔
813
  }
814

815
  // Back substitution
816
  for (int i = n - 2; i >= 0; i--) {
10,354,762✔
817
    z[i] = z[i] - c_new[i] * z[i + 1];
10,252,484✔
818
  }
819
}
102,278✔
820

821
double spline_interpolate(
×
822
  int n, const double x[], const double y[], const double z[], double xint)
823
{
824
  // Find the lower bounding index in x of xint
825
  int i = n - 1;
×
826
  while (--i) {
×
827
    if (xint >= x[i])
×
828
      break;
×
829
  }
830

831
  double h = x[i + 1] - x[i];
×
832
  double r = xint - x[i];
×
833

834
  // Compute the coefficients
835
  double b = (y[i + 1] - y[i]) / h - (h / 6.0) * (z[i + 1] + 2.0 * z[i]);
×
836
  double c = z[i] / 2.0;
×
837
  double d = (z[i + 1] - z[i]) / (h * 6.0);
×
838

839
  return y[i] + b * r + c * r * r + d * r * r * r;
×
840
}
841

842
double spline_integrate(int n, const double x[], const double y[],
10,252,484✔
843
  const double z[], double xa, double xb)
844
{
845
  // Find the lower bounding index in x of the lower limit of integration.
846
  int ia = n - 1;
10,252,484✔
847
  while (--ia) {
685,292,674✔
848
    if (xa >= x[ia])
685,190,396✔
849
      break;
10,150,206✔
850
  }
851

852
  // Find the lower bounding index in x of the upper limit of integration.
853
  int ib = n - 1;
10,252,484✔
854
  while (--ib) {
675,142,468✔
855
    if (xb >= x[ib])
675,142,468✔
856
      break;
10,252,484✔
857
  }
858

859
  // Evaluate the integral
860
  double s = 0.0;
10,252,484✔
861
  for (int i = ia; i <= ib; i++) {
30,655,174✔
862
    double h = x[i + 1] - x[i];
20,402,690✔
863

864
    // Compute the coefficients
865
    double b = (y[i + 1] - y[i]) / h - (h / 6.0) * (z[i + 1] + 2.0 * z[i]);
20,402,690✔
866
    double c = z[i] / 2.0;
20,402,690✔
867
    double d = (z[i + 1] - z[i]) / (h * 6.0);
20,402,690✔
868

869
    // Subtract the integral from x[ia] to xa
870
    if (i == ia) {
20,402,690✔
871
      double r = xa - x[ia];
10,252,484✔
872
      s = s - (y[i] * r + b / 2.0 * r * r + c / 3.0 * r * r * r +
10,252,484✔
873
                d / 4.0 * r * r * r * r);
10,252,484✔
874
    }
875

876
    // Integrate from x[ib] to xb in final interval
877
    if (i == ib) {
20,402,690✔
878
      h = xb - x[ib];
10,252,484✔
879
    }
880

881
    // Accumulate the integral
882
    s = s + y[i] * h + b / 2.0 * h * h + c / 3.0 * h * h * h +
20,402,690✔
883
        d / 4.0 * h * h * h * h;
20,402,690✔
884
  }
885

886
  return s;
10,252,484✔
887
}
888

889
std::complex<double> faddeeva(std::complex<double> z)
3,269,167✔
890
{
891
  // Technically, the value we want is given by the equation:
892
  // w(z) = I/pi * Integrate[Exp[-t^2]/(z-t), {t, -Infinity, Infinity}]
893
  // as shown in Equation 63 from Hwang, R. N. "A rigorous pole
894
  // representation of multilevel cross sections and its practical
895
  // applications." Nucl. Sci. Eng. 96.3 (1987): 192-209.
896
  //
897
  // The MIT Faddeeva function evaluates w(z) = exp(-z^2)erfc(-iz). These
898
  // two forms of the Faddeeva function are related by a transformation.
899
  //
900
  // If we call the integral form w_int, and the function form w_fun:
901
  // For imag(z) > 0, w_int(z) = w_fun(z)
902
  // For imag(z) < 0, w_int(z) = -conjg(w_fun(conjg(z)))
903

904
  // Note that Faddeeva::w will interpret zero as machine epsilon
905
  return z.imag() > 0.0 ? Faddeeva::w(z)
3,269,167✔
906
                        : -std::conj(Faddeeva::w(std::conj(z)));
6,538,334✔
907
}
908

909
std::complex<double> w_derivative(std::complex<double> z, int order)
3,925,317✔
910
{
911
  using namespace std::complex_literals;
912
  switch (order) {
3,925,317✔
913
  case 0:
1,308,439✔
914
    return faddeeva(z);
1,308,439✔
915
  case 1:
1,308,439✔
916
    return -2.0 * z * faddeeva(z) + 2.0i / SQRT_PI;
2,616,878✔
917
  default:
1,308,439✔
918
    return -2.0 * z * w_derivative(z, order - 1) -
1,308,439✔
919
           2.0 * (order - 1) * w_derivative(z, order - 2);
3,925,317✔
920
  }
921
}
922

NEW
923
double exprel(double x)
×
924
{
NEW
925
  if (std::abs(x) < 1e-16)
×
NEW
926
    return 1.0;
×
927
  else {
NEW
928
    return std::expm1(x) / x;
×
929
  }
930
}
931

932
double lambert_w0(double x)
143✔
933
{
934
  return LambertW::lambert_w0(x);
143✔
935
}
936

937
double lambert_wm1(double x)
33✔
938
{
939
  return LambertW::lambert_wm1(x);
33✔
940
}
941

942
} // namespace openmc
STATUS · Troubleshooting · Open an Issue · Sales · Support · CAREERS · ENTERPRISE · START FREE · SCHEDULE DEMO
ANNOUNCEMENTS · TWITTER · TOS & SLA · Supported CI Services · What's a CI service? · Automated Testing

© 2026 Coveralls, Inc