xref: /petsc/include/petscdt.h (revision 4ad8454beace47809662cdae21ee081016eaa39a)
1 /*
2   Common tools for constructing discretizations
3 */
4 #pragma once
5 
6 #include <petscsys.h>
7 #include <petscdmtypes.h>
8 #include <petscistypes.h>
9 
10 /* SUBMANSEC = DT */
11 
12 PETSC_EXTERN PetscClassId PETSCQUADRATURE_CLASSID;
13 
14 /*S
15   PetscQuadrature - Quadrature rule for numerical integration.
16 
17   Level: beginner
18 
19 .seealso: `PetscQuadratureCreate()`, `PetscQuadratureDestroy()`
20 S*/
21 typedef struct _p_PetscQuadrature *PetscQuadrature;
22 
23 /*E
24   PetscGaussLobattoLegendreCreateType - algorithm used to compute the Gauss-Lobatto-Legendre nodes and weights
25 
26   Values:
27 +  `PETSCGAUSSLOBATTOLEGENDRE_VIA_LINEAR_ALGEBRA` - compute the nodes via linear algebra
28 -  `PETSCGAUSSLOBATTOLEGENDRE_VIA_NEWTON`         - compute the nodes by solving a nonlinear equation with Newton's method
29 
30   Level: intermediate
31 
32 .seealso: `PetscQuadrature`
33 E*/
34 typedef enum {
35   PETSCGAUSSLOBATTOLEGENDRE_VIA_LINEAR_ALGEBRA,
36   PETSCGAUSSLOBATTOLEGENDRE_VIA_NEWTON
37 } PetscGaussLobattoLegendreCreateType;
38 
39 /*E
40   PetscDTNodeType - A description of strategies for generating nodes (both
41   quadrature nodes and nodes for Lagrange polynomials)
42 
43   Values:
44 + `PETSCDTNODES_DEFAULT`     - Nodes chosen by PETSc
45 . `PETSCDTNODES_GAUSSJACOBI` - Nodes at either Gauss-Jacobi or Gauss-Lobatto-Jacobi quadrature points
46 . `PETSCDTNODES_EQUISPACED`  - Nodes equispaced either including the endpoints or excluding them
47 - `PETSCDTNODES_TANHSINH`    - Nodes at Tanh-Sinh quadrature points
48 
49   Level: intermediate
50 
51   Note:
52   A `PetscDTNodeType` can be paired with a `PetscBool` to indicate whether
53   the nodes include endpoints or not, and in the case of `PETSCDT_GAUSSJACOBI`
54   with exponents for the weight function.
55 
56 .seealso: `PetscQuadrature`
57 E*/
58 typedef enum {
59   PETSCDTNODES_DEFAULT = -1,
60   PETSCDTNODES_GAUSSJACOBI,
61   PETSCDTNODES_EQUISPACED,
62   PETSCDTNODES_TANHSINH
63 } PetscDTNodeType;
64 
65 PETSC_EXTERN const char *const *const PetscDTNodeTypes;
66 
67 /*E
68   PetscDTSimplexQuadratureType - A description of classes of quadrature rules for simplices
69 
70   Values:
71 +  `PETSCDTSIMPLEXQUAD_DEFAULT` - Quadrature rule chosen by PETSc
72 .  `PETSCDTSIMPLEXQUAD_CONIC`   - Quadrature rules constructed as
73                                   conically-warped tensor products of 1D
74                                   Gauss-Jacobi quadrature rules.  These are
75                                   explicitly computable in any dimension for any
76                                   degree, and the tensor-product structure can be
77                                   exploited by sum-factorization methods, but
78                                   they are not efficient in terms of nodes per
79                                   polynomial degree.
80 -  `PETSCDTSIMPLEXQUAD_MINSYM`  - Quadrature rules that are fully symmetric
81                                   (symmetries of the simplex preserve the nodes
82                                   and weights) with minimal (or near minimal)
83                                   number of nodes.  In dimensions higher than 1
84                                   these are not simple to compute, so lookup
85                                   tables are used.
86 
87   Level: intermediate
88 
89 .seealso: `PetscQuadrature`, `PetscDTSimplexQuadrature()`
90 E*/
91 typedef enum {
92   PETSCDTSIMPLEXQUAD_DEFAULT = -1,
93   PETSCDTSIMPLEXQUAD_CONIC   = 0,
94   PETSCDTSIMPLEXQUAD_MINSYM
95 } PetscDTSimplexQuadratureType;
96 
97 PETSC_EXTERN const char *const *const PetscDTSimplexQuadratureTypes;
98 
99 PETSC_EXTERN PetscErrorCode PetscQuadratureCreate(MPI_Comm, PetscQuadrature *);
100 PETSC_EXTERN PetscErrorCode PetscQuadratureDuplicate(PetscQuadrature, PetscQuadrature *);
101 PETSC_EXTERN PetscErrorCode PetscQuadratureGetCellType(PetscQuadrature, DMPolytopeType *);
102 PETSC_EXTERN PetscErrorCode PetscQuadratureSetCellType(PetscQuadrature, DMPolytopeType);
103 PETSC_EXTERN PetscErrorCode PetscQuadratureGetOrder(PetscQuadrature, PetscInt *);
104 PETSC_EXTERN PetscErrorCode PetscQuadratureSetOrder(PetscQuadrature, PetscInt);
105 PETSC_EXTERN PetscErrorCode PetscQuadratureGetNumComponents(PetscQuadrature, PetscInt *);
106 PETSC_EXTERN PetscErrorCode PetscQuadratureSetNumComponents(PetscQuadrature, PetscInt);
107 PETSC_EXTERN PetscErrorCode PetscQuadratureEqual(PetscQuadrature, PetscQuadrature, PetscBool *);
108 PETSC_EXTERN PetscErrorCode PetscQuadratureGetData(PetscQuadrature, PetscInt *, PetscInt *, PetscInt *, const PetscReal *[], const PetscReal *[]);
109 PETSC_EXTERN PetscErrorCode PetscQuadratureSetData(PetscQuadrature, PetscInt, PetscInt, PetscInt, const PetscReal[], const PetscReal[]);
110 PETSC_EXTERN PetscErrorCode PetscQuadratureView(PetscQuadrature, PetscViewer);
111 PETSC_EXTERN PetscErrorCode PetscQuadratureDestroy(PetscQuadrature *);
112 
113 PETSC_EXTERN PetscErrorCode PetscDTTensorQuadratureCreate(PetscQuadrature, PetscQuadrature, PetscQuadrature *);
114 PETSC_EXTERN PetscErrorCode PetscQuadratureExpandComposite(PetscQuadrature, PetscInt, const PetscReal[], const PetscReal[], PetscQuadrature *);
115 PETSC_EXTERN PetscErrorCode PetscQuadratureComputePermutations(PetscQuadrature, PetscInt *, IS *[]);
116 
117 PETSC_EXTERN PetscErrorCode PetscQuadraturePushForward(PetscQuadrature, PetscInt, const PetscReal[], const PetscReal[], const PetscReal[], PetscInt, PetscQuadrature *);
118 
119 PETSC_EXTERN PetscErrorCode PetscDTLegendreEval(PetscInt, const PetscReal *, PetscInt, const PetscInt *, PetscReal *, PetscReal *, PetscReal *);
120 PETSC_EXTERN PetscErrorCode PetscDTJacobiNorm(PetscReal, PetscReal, PetscInt, PetscReal *);
121 PETSC_EXTERN PetscErrorCode PetscDTJacobiEval(PetscInt, PetscReal, PetscReal, const PetscReal *, PetscInt, const PetscInt *, PetscReal *, PetscReal *, PetscReal *);
122 PETSC_EXTERN PetscErrorCode PetscDTJacobiEvalJet(PetscReal, PetscReal, PetscInt, const PetscReal[], PetscInt, PetscInt, PetscReal[]);
123 PETSC_EXTERN PetscErrorCode PetscDTPKDEvalJet(PetscInt, PetscInt, const PetscReal[], PetscInt, PetscInt, PetscReal[]);
124 PETSC_EXTERN PetscErrorCode PetscDTPTrimmedSize(PetscInt, PetscInt, PetscInt, PetscInt *);
125 PETSC_EXTERN PetscErrorCode PetscDTPTrimmedEvalJet(PetscInt, PetscInt, const PetscReal[], PetscInt, PetscInt, PetscInt, PetscReal[]);
126 PETSC_EXTERN PetscErrorCode PetscDTGaussQuadrature(PetscInt, PetscReal, PetscReal, PetscReal *, PetscReal *);
127 PETSC_EXTERN PetscErrorCode PetscDTGaussJacobiQuadrature(PetscInt, PetscReal, PetscReal, PetscReal, PetscReal, PetscReal *, PetscReal *);
128 PETSC_EXTERN PetscErrorCode PetscDTGaussLobattoJacobiQuadrature(PetscInt, PetscReal, PetscReal, PetscReal, PetscReal, PetscReal *, PetscReal *);
129 PETSC_EXTERN PetscErrorCode PetscDTGaussLobattoLegendreQuadrature(PetscInt, PetscGaussLobattoLegendreCreateType, PetscReal *, PetscReal *);
130 PETSC_EXTERN PetscErrorCode PetscDTReconstructPoly(PetscInt, PetscInt, const PetscReal *, PetscInt, const PetscReal *, PetscReal *);
131 PETSC_EXTERN PetscErrorCode PetscDTGaussTensorQuadrature(PetscInt, PetscInt, PetscInt, PetscReal, PetscReal, PetscQuadrature *);
132 PETSC_EXTERN PetscErrorCode PetscDTStroudConicalQuadrature(PetscInt, PetscInt, PetscInt, PetscReal, PetscReal, PetscQuadrature *);
133 PETSC_EXTERN PetscErrorCode PetscDTSimplexQuadrature(PetscInt, PetscInt, PetscDTSimplexQuadratureType, PetscQuadrature *);
134 PETSC_EXTERN PetscErrorCode PetscDTCreateDefaultQuadrature(DMPolytopeType, PetscInt, PetscQuadrature *, PetscQuadrature *);
135 
136 PETSC_EXTERN PetscErrorCode PetscDTTanhSinhTensorQuadrature(PetscInt, PetscInt, PetscReal, PetscReal, PetscQuadrature *);
137 PETSC_EXTERN PetscErrorCode PetscDTTanhSinhIntegrate(void (*)(const PetscReal[], void *, PetscReal *), PetscReal, PetscReal, PetscInt, void *, PetscReal *);
138 PETSC_EXTERN PetscErrorCode PetscDTTanhSinhIntegrateMPFR(void (*)(const PetscReal[], void *, PetscReal *), PetscReal, PetscReal, PetscInt, void *, PetscReal *);
139 
140 PETSC_EXTERN PetscErrorCode PetscGaussLobattoLegendreIntegrate(PetscInt, PetscReal *, PetscReal *, const PetscReal *, PetscReal *);
141 PETSC_EXTERN PetscErrorCode PetscGaussLobattoLegendreElementLaplacianCreate(PetscInt, PetscReal *, PetscReal *, PetscReal ***);
142 PETSC_EXTERN PetscErrorCode PetscGaussLobattoLegendreElementLaplacianDestroy(PetscInt, PetscReal *, PetscReal *, PetscReal ***);
143 PETSC_EXTERN PetscErrorCode PetscGaussLobattoLegendreElementGradientCreate(PetscInt, PetscReal *, PetscReal *, PetscReal ***, PetscReal ***);
144 PETSC_EXTERN PetscErrorCode PetscGaussLobattoLegendreElementGradientDestroy(PetscInt, PetscReal *, PetscReal *, PetscReal ***, PetscReal ***);
145 PETSC_EXTERN PetscErrorCode PetscGaussLobattoLegendreElementAdvectionCreate(PetscInt, PetscReal *, PetscReal *, PetscReal ***);
146 PETSC_EXTERN PetscErrorCode PetscGaussLobattoLegendreElementAdvectionDestroy(PetscInt, PetscReal *, PetscReal *, PetscReal ***);
147 PETSC_EXTERN PetscErrorCode PetscGaussLobattoLegendreElementMassCreate(PetscInt, PetscReal *, PetscReal *, PetscReal ***);
148 PETSC_EXTERN PetscErrorCode PetscGaussLobattoLegendreElementMassDestroy(PetscInt, PetscReal *, PetscReal *, PetscReal ***);
149 
150 /*MC
151   PETSC_FORM_DEGREE_UNDEFINED - Indicates that a field does not have
152   a well-defined form degree in exterior calculus.
153 
154   Level: advanced
155 
156 .seealso: `PetscDTAltV`, `PetscDualSpaceGetFormDegree()`
157 M*/
158 #define PETSC_FORM_DEGREE_UNDEFINED PETSC_INT_MIN
159 
160 PETSC_EXTERN PetscErrorCode PetscDTAltVApply(PetscInt, PetscInt, const PetscReal *, const PetscReal *, PetscReal *);
161 PETSC_EXTERN PetscErrorCode PetscDTAltVWedge(PetscInt, PetscInt, PetscInt, const PetscReal *, const PetscReal *, PetscReal *);
162 PETSC_EXTERN PetscErrorCode PetscDTAltVWedgeMatrix(PetscInt, PetscInt, PetscInt, const PetscReal *, PetscReal *);
163 PETSC_EXTERN PetscErrorCode PetscDTAltVPullback(PetscInt, PetscInt, const PetscReal *, PetscInt, const PetscReal *, PetscReal *);
164 PETSC_EXTERN PetscErrorCode PetscDTAltVPullbackMatrix(PetscInt, PetscInt, const PetscReal *, PetscInt, PetscReal *);
165 PETSC_EXTERN PetscErrorCode PetscDTAltVInterior(PetscInt, PetscInt, const PetscReal *, const PetscReal *, PetscReal *);
166 PETSC_EXTERN PetscErrorCode PetscDTAltVInteriorMatrix(PetscInt, PetscInt, const PetscReal *, PetscReal *);
167 PETSC_EXTERN PetscErrorCode PetscDTAltVInteriorPattern(PetscInt, PetscInt, PetscInt (*)[3]);
168 PETSC_EXTERN PetscErrorCode PetscDTAltVStar(PetscInt, PetscInt, PetscInt, const PetscReal *, PetscReal *);
169 
170 PETSC_EXTERN PetscErrorCode PetscDTBaryToIndex(PetscInt, PetscInt, const PetscInt[], PetscInt *);
171 PETSC_EXTERN PetscErrorCode PetscDTIndexToBary(PetscInt, PetscInt, PetscInt, PetscInt[]);
172 PETSC_EXTERN PetscErrorCode PetscDTGradedOrderToIndex(PetscInt, const PetscInt[], PetscInt *);
173 PETSC_EXTERN PetscErrorCode PetscDTIndexToGradedOrder(PetscInt, PetscInt, PetscInt[]);
174 
175 #if defined(PETSC_USE_64BIT_INDICES)
176   #define PETSC_FACTORIAL_MAX 20
177   #define PETSC_BINOMIAL_MAX  61
178 #else
179   #define PETSC_FACTORIAL_MAX 12
180   #define PETSC_BINOMIAL_MAX  29
181 #endif
182 
183 /*MC
184    PetscDTFactorial - Approximate n! as a real number
185 
186    Input Parameter:
187 .  n - a non-negative integer
188 
189    Output Parameter:
190 .  factorial - n!
191 
192    Level: beginner
193 
194 .seealso: `PetscDTFactorialInt()`, `PetscDTBinomialInt()`, `PetscDTBinomial()`
195 M*/
196 static inline PetscErrorCode PetscDTFactorial(PetscInt n, PetscReal *factorial)
197 {
198   PetscReal f = 1.0;
199 
200   PetscFunctionBegin;
201   *factorial = -1.0;
202   PetscCheck(n >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Factorial called with negative number %" PetscInt_FMT, n);
203   for (PetscInt i = 1; i < n + 1; ++i) f *= (PetscReal)i;
204   *factorial = f;
205   PetscFunctionReturn(PETSC_SUCCESS);
206 }
207 
208 /*MC
209    PetscDTFactorialInt - Compute n! as an integer
210 
211    Input Parameter:
212 .  n - a non-negative integer
213 
214    Output Parameter:
215 .  factorial - n!
216 
217    Level: beginner
218 
219    Note:
220    This is limited to `n` such that n! can be represented by `PetscInt`, which is 12 if `PetscInt` is a signed 32-bit integer and 20 if `PetscInt` is a signed 64-bit integer.
221 
222 .seealso: `PetscDTFactorial()`, `PetscDTBinomialInt()`, `PetscDTBinomial()`
223 M*/
224 static inline PetscErrorCode PetscDTFactorialInt(PetscInt n, PetscInt *factorial)
225 {
226   PetscInt facLookup[13] = {1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800, 39916800, 479001600};
227 
228   PetscFunctionBegin;
229   *factorial = -1;
230   PetscCheck(n >= 0 && n <= PETSC_FACTORIAL_MAX, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Number of elements %" PetscInt_FMT " is not in supported range [0,%d]", n, PETSC_FACTORIAL_MAX);
231   if (n <= 12) {
232     *factorial = facLookup[n];
233   } else {
234     PetscInt f = facLookup[12];
235     PetscInt i;
236 
237     for (i = 13; i < n + 1; ++i) f *= i;
238     *factorial = f;
239   }
240   PetscFunctionReturn(PETSC_SUCCESS);
241 }
242 
243 /*MC
244    PetscDTBinomial - Approximate the binomial coefficient `n` choose `k`
245 
246    Input Parameters:
247 +  n - a non-negative integer
248 -  k - an integer between 0 and `n`, inclusive
249 
250    Output Parameter:
251 .  binomial - approximation of the binomial coefficient `n` choose `k`
252 
253    Level: beginner
254 
255 .seealso: `PetscDTFactorial()`, `PetscDTFactorialInt()`, `PetscDTBinomialInt()`, `PetscDTEnumPerm()`
256 M*/
257 static inline PetscErrorCode PetscDTBinomial(PetscInt n, PetscInt k, PetscReal *binomial)
258 {
259   PetscFunctionBeginHot;
260   *binomial = -1.0;
261   PetscCheck(n >= 0 && k >= 0 && k <= n, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Binomial arguments (%" PetscInt_FMT " %" PetscInt_FMT ") must be non-negative, k <= n", n, k);
262   if (n <= 3) {
263     PetscInt binomLookup[4][4] = {
264       {1, 0, 0, 0},
265       {1, 1, 0, 0},
266       {1, 2, 1, 0},
267       {1, 3, 3, 1}
268     };
269 
270     *binomial = (PetscReal)binomLookup[n][k];
271   } else {
272     PetscReal binom = 1.0;
273 
274     k = PetscMin(k, n - k);
275     for (PetscInt i = 0; i < k; i++) binom = (binom * (PetscReal)(n - i)) / (PetscReal)(i + 1);
276     *binomial = binom;
277   }
278   PetscFunctionReturn(PETSC_SUCCESS);
279 }
280 
281 /*MC
282    PetscDTBinomialInt - Compute the binomial coefficient `n` choose `k`
283 
284    Input Parameters:
285 +  n - a non-negative integer
286 -  k - an integer between 0 and `n`, inclusive
287 
288    Output Parameter:
289 .  binomial - the binomial coefficient `n` choose `k`
290 
291    Level: beginner
292 
293    Note:
294    This is limited by integers that can be represented by `PetscInt`.
295 
296    Use `PetscDTBinomial()` for real number approximations of larger values
297 
298 .seealso: `PetscDTFactorial()`, `PetscDTFactorialInt()`, `PetscDTBinomial()`, `PetscDTEnumPerm()`
299 M*/
300 static inline PetscErrorCode PetscDTBinomialInt(PetscInt n, PetscInt k, PetscInt *binomial)
301 {
302   PetscInt bin;
303 
304   PetscFunctionBegin;
305   *binomial = -1;
306   PetscCheck(n >= 0 && k >= 0 && k <= n, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Binomial arguments (%" PetscInt_FMT " %" PetscInt_FMT ") must be non-negative, k <= n", n, k);
307   PetscCheck(n <= PETSC_BINOMIAL_MAX, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Binomial elements %" PetscInt_FMT " is larger than max for PetscInt, %d", n, PETSC_BINOMIAL_MAX);
308   if (n <= 3) {
309     PetscInt binomLookup[4][4] = {
310       {1, 0, 0, 0},
311       {1, 1, 0, 0},
312       {1, 2, 1, 0},
313       {1, 3, 3, 1}
314     };
315 
316     bin = binomLookup[n][k];
317   } else {
318     PetscInt binom = 1;
319 
320     k = PetscMin(k, n - k);
321     for (PetscInt i = 0; i < k; i++) binom = (binom * (n - i)) / (i + 1);
322     bin = binom;
323   }
324   *binomial = bin;
325   PetscFunctionReturn(PETSC_SUCCESS);
326 }
327 
328 /*MC
329    PetscDTEnumPerm - Get a permutation of `n` integers from its encoding into the integers [0, n!) as a sequence of swaps.
330 
331    Input Parameters:
332 +  n - a non-negative integer (see note about limits below)
333 -  k - an integer in [0, n!)
334 
335    Output Parameters:
336 +  perm  - the permuted list of the integers [0, ..., n-1]
337 -  isOdd - if not `NULL`, returns whether the permutation used an even or odd number of swaps.
338 
339    Level: intermediate
340 
341    Notes:
342    A permutation can be described by the operations that convert the lists [0, 1, ..., n-1] into the permutation,
343    by a sequence of swaps, where the ith step swaps whatever number is in ith position with a number that is in
344    some position j >= i.  This swap is encoded as the difference (j - i).  The difference d_i at step i is less than
345    (n - i).  This sequence of n-1 differences [d_0, ..., d_{n-2}] is encoded as the number
346    (n-1)! * d_0 + (n-2)! * d_1 + ... + 1! * d_{n-2}.
347 
348    Limited to `n` such that `n`! can be represented by `PetscInt`, which is 12 if `PetscInt` is a signed 32-bit integer and 20 if `PetscInt` is a signed 64-bit integer.
349 
350 .seealso: `PetscDTFactorial()`, `PetscDTFactorialInt()`, `PetscDTBinomial()`, `PetscDTBinomialInt()`, `PetscDTPermIndex()`
351 M*/
352 static inline PetscErrorCode PetscDTEnumPerm(PetscInt n, PetscInt k, PetscInt *perm, PetscBool *isOdd)
353 {
354   PetscInt  odd = 0;
355   PetscInt  i;
356   PetscInt  work[PETSC_FACTORIAL_MAX];
357   PetscInt *w;
358 
359   PetscFunctionBegin;
360   if (isOdd) *isOdd = PETSC_FALSE;
361   PetscCheck(n >= 0 && n <= PETSC_FACTORIAL_MAX, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Number of elements %" PetscInt_FMT " is not in supported range [0,%d]", n, PETSC_FACTORIAL_MAX);
362   if (n >= 2) {
363     w = &work[n - 2];
364     for (i = 2; i <= n; i++) {
365       *(w--) = k % i;
366       k /= i;
367     }
368   }
369   for (i = 0; i < n; i++) perm[i] = i;
370   for (i = 0; i < n - 1; i++) {
371     PetscInt s    = work[i];
372     PetscInt swap = perm[i];
373 
374     perm[i]     = perm[i + s];
375     perm[i + s] = swap;
376     odd ^= (!!s);
377   }
378   if (isOdd) *isOdd = odd ? PETSC_TRUE : PETSC_FALSE;
379   PetscFunctionReturn(PETSC_SUCCESS);
380 }
381 
382 /*MC
383    PetscDTPermIndex - Encode a permutation of n into an integer in [0, n!).  This inverts `PetscDTEnumPerm()`.
384 
385    Input Parameters:
386 +  n    - a non-negative integer (see note about limits below)
387 -  perm - the permuted list of the integers [0, ..., n-1]
388 
389    Output Parameters:
390 +  k     - an integer in [0, n!)
391 -  isOdd - if not `NULL`, returns whether the permutation used an even or odd number of swaps.
392 
393    Level: beginner
394 
395    Note:
396    Limited to `n` such that `n`! can be represented by `PetscInt`, which is 12 if `PetscInt` is a signed 32-bit integer and 20 if `PetscInt` is a signed 64-bit integer.
397 
398 .seealso: `PetscDTFactorial()`, `PetscDTFactorialInt()`, `PetscDTBinomial()`, `PetscDTBinomialInt()`, `PetscDTEnumPerm()`
399 M*/
400 static inline PetscErrorCode PetscDTPermIndex(PetscInt n, const PetscInt *perm, PetscInt *k, PetscBool *isOdd)
401 {
402   PetscInt odd = 0;
403   PetscInt i, idx;
404   PetscInt work[PETSC_FACTORIAL_MAX];
405   PetscInt iwork[PETSC_FACTORIAL_MAX];
406 
407   PetscFunctionBeginHot;
408   *k = -1;
409   if (isOdd) *isOdd = PETSC_FALSE;
410   PetscCheck(n >= 0 && n <= PETSC_FACTORIAL_MAX, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Number of elements %" PetscInt_FMT " is not in supported range [0,%d]", n, PETSC_FACTORIAL_MAX);
411   for (i = 0; i < n; i++) work[i] = i;  /* partial permutation */
412   for (i = 0; i < n; i++) iwork[i] = i; /* partial permutation inverse */
413   for (idx = 0, i = 0; i < n - 1; i++) {
414     PetscInt j    = perm[i];
415     PetscInt icur = work[i];
416     PetscInt jloc = iwork[j];
417     PetscInt diff = jloc - i;
418 
419     idx = idx * (n - i) + diff;
420     /* swap (i, jloc) */
421     work[i]     = j;
422     work[jloc]  = icur;
423     iwork[j]    = i;
424     iwork[icur] = jloc;
425     odd ^= (!!diff);
426   }
427   *k = idx;
428   if (isOdd) *isOdd = odd ? PETSC_TRUE : PETSC_FALSE;
429   PetscFunctionReturn(PETSC_SUCCESS);
430 }
431 
432 /*MC
433    PetscDTEnumSubset - Get an ordered subset of the integers [0, ..., n - 1] from its encoding as an integers in [0, n choose k).
434    The encoding is in lexicographic order.
435 
436    Input Parameters:
437 +  n - a non-negative integer (see note about limits below)
438 .  k - an integer in [0, n]
439 -  j - an index in [0, n choose k)
440 
441    Output Parameter:
442 .  subset - the jth subset of size k of the integers [0, ..., n - 1]
443 
444    Level: beginner
445 
446    Note:
447    Limited by arguments such that `n` choose `k` can be represented by `PetscInt`
448 
449 .seealso: `PetscDTSubsetIndex()`, `PetscDTFactorial()`, `PetscDTFactorialInt()`, `PetscDTBinomial()`, `PetscDTBinomialInt()`, `PetscDTEnumPerm()`, `PetscDTPermIndex()`
450 M*/
451 static inline PetscErrorCode PetscDTEnumSubset(PetscInt n, PetscInt k, PetscInt j, PetscInt *subset)
452 {
453   PetscInt Nk;
454 
455   PetscFunctionBeginHot;
456   PetscCall(PetscDTBinomialInt(n, k, &Nk));
457   for (PetscInt i = 0, l = 0; i < n && l < k; i++) {
458     PetscInt Nminuskminus = (Nk * (k - l)) / (n - i);
459     PetscInt Nminusk      = Nk - Nminuskminus;
460 
461     if (j < Nminuskminus) {
462       subset[l++] = i;
463       Nk          = Nminuskminus;
464     } else {
465       j -= Nminuskminus;
466       Nk = Nminusk;
467     }
468   }
469   PetscFunctionReturn(PETSC_SUCCESS);
470 }
471 
472 /*MC
473    PetscDTSubsetIndex - Convert an ordered subset of k integers from the set [0, ..., n - 1] to its encoding as an integers in [0, n choose k) in lexicographic order.
474    This is the inverse of `PetscDTEnumSubset`.
475 
476    Input Parameters:
477 +  n      - a non-negative integer (see note about limits below)
478 .  k      - an integer in [0, n]
479 -  subset - an ordered subset of the integers [0, ..., n - 1]
480 
481    Output Parameter:
482 .  index - the rank of the subset in lexicographic order
483 
484    Level: beginner
485 
486    Note:
487    Limited by arguments such that `n` choose `k` can be represented by `PetscInt`
488 
489 .seealso: `PetscDTEnumSubset()`, `PetscDTFactorial()`, `PetscDTFactorialInt()`, `PetscDTBinomial()`, `PetscDTBinomialInt()`, `PetscDTEnumPerm()`, `PetscDTPermIndex()`
490 M*/
491 static inline PetscErrorCode PetscDTSubsetIndex(PetscInt n, PetscInt k, const PetscInt *subset, PetscInt *index)
492 {
493   PetscInt j = 0, Nk;
494 
495   PetscFunctionBegin;
496   *index = -1;
497   PetscCall(PetscDTBinomialInt(n, k, &Nk));
498   for (PetscInt i = 0, l = 0; i < n && l < k; i++) {
499     PetscInt Nminuskminus = (Nk * (k - l)) / (n - i);
500     PetscInt Nminusk      = Nk - Nminuskminus;
501 
502     if (subset[l] == i) {
503       l++;
504       Nk = Nminuskminus;
505     } else {
506       j += Nminuskminus;
507       Nk = Nminusk;
508     }
509   }
510   *index = j;
511   PetscFunctionReturn(PETSC_SUCCESS);
512 }
513 
514 /*MC
515    PetscDTEnumSubset - Split the integers [0, ..., n - 1] into two complementary ordered subsets, the first subset of size k and being the jth subset of that size in lexicographic order.
516 
517    Input Parameters:
518 +  n - a non-negative integer (see note about limits below)
519 .  k - an integer in [0, n]
520 -  j - an index in [0, n choose k)
521 
522    Output Parameters:
523 +  perm  - the jth subset of size k of the integers [0, ..., n - 1], followed by its complementary set.
524 -  isOdd - if not `NULL`, return whether perm is an even or odd permutation.
525 
526    Level: beginner
527 
528    Note:
529    Limited by arguments such that `n` choose `k` can be represented by `PetscInt`
530 
531 .seealso: `PetscDTEnumSubset()`, `PetscDTSubsetIndex()`, `PetscDTFactorial()`, `PetscDTFactorialInt()`, `PetscDTBinomial()`, `PetscDTBinomialInt()`, `PetscDTEnumPerm()`,
532           `PetscDTPermIndex()`
533 M*/
534 static inline PetscErrorCode PetscDTEnumSplit(PetscInt n, PetscInt k, PetscInt j, PetscInt *perm, PetscBool *isOdd)
535 {
536   PetscInt  i, l, m, Nk, odd = 0;
537   PetscInt *subcomp = PetscSafePointerPlusOffset(perm, k);
538 
539   PetscFunctionBegin;
540   if (isOdd) *isOdd = PETSC_FALSE;
541   PetscCall(PetscDTBinomialInt(n, k, &Nk));
542   for (i = 0, l = 0, m = 0; i < n && l < k; i++) {
543     PetscInt Nminuskminus = (Nk * (k - l)) / (n - i);
544     PetscInt Nminusk      = Nk - Nminuskminus;
545 
546     if (j < Nminuskminus) {
547       perm[l++] = i;
548       Nk        = Nminuskminus;
549     } else {
550       subcomp[m++] = i;
551       j -= Nminuskminus;
552       odd ^= ((k - l) & 1);
553       Nk = Nminusk;
554     }
555   }
556   for (; i < n; i++) subcomp[m++] = i;
557   if (isOdd) *isOdd = odd ? PETSC_TRUE : PETSC_FALSE;
558   PetscFunctionReturn(PETSC_SUCCESS);
559 }
560 
561 struct _p_PetscTabulation {
562   PetscInt    K;    /* Indicates a k-jet, namely tabulated derivatives up to order k */
563   PetscInt    Nr;   /* The number of tabulation replicas (often 1) */
564   PetscInt    Np;   /* The number of tabulation points in a replica */
565   PetscInt    Nb;   /* The number of functions tabulated */
566   PetscInt    Nc;   /* The number of function components */
567   PetscInt    cdim; /* The coordinate dimension */
568   PetscReal **T;    /* The tabulation T[K] of functions and their derivatives
569                        T[0] = B[Nr*Np][Nb][Nc]:             The basis function values at quadrature points
570                        T[1] = D[Nr*Np][Nb][Nc][cdim]:       The basis function derivatives at quadrature points
571                        T[2] = H[Nr*Np][Nb][Nc][cdim][cdim]: The basis function second derivatives at quadrature points */
572 };
573 typedef struct _p_PetscTabulation *PetscTabulation;
574 
575 typedef PetscErrorCode (*PetscProbFunc)(const PetscReal[], const PetscReal[], PetscReal[]);
576 
577 typedef enum {
578   DTPROB_DENSITY_CONSTANT,
579   DTPROB_DENSITY_GAUSSIAN,
580   DTPROB_DENSITY_MAXWELL_BOLTZMANN,
581   DTPROB_NUM_DENSITY
582 } DTProbDensityType;
583 PETSC_EXTERN const char *const DTProbDensityTypes[];
584 
585 PETSC_EXTERN PetscErrorCode PetscPDFMaxwellBoltzmann1D(const PetscReal[], const PetscReal[], PetscReal[]);
586 PETSC_EXTERN PetscErrorCode PetscCDFMaxwellBoltzmann1D(const PetscReal[], const PetscReal[], PetscReal[]);
587 PETSC_EXTERN PetscErrorCode PetscPDFMaxwellBoltzmann2D(const PetscReal[], const PetscReal[], PetscReal[]);
588 PETSC_EXTERN PetscErrorCode PetscCDFMaxwellBoltzmann2D(const PetscReal[], const PetscReal[], PetscReal[]);
589 PETSC_EXTERN PetscErrorCode PetscPDFMaxwellBoltzmann3D(const PetscReal[], const PetscReal[], PetscReal[]);
590 PETSC_EXTERN PetscErrorCode PetscCDFMaxwellBoltzmann3D(const PetscReal[], const PetscReal[], PetscReal[]);
591 PETSC_EXTERN PetscErrorCode PetscPDFGaussian1D(const PetscReal[], const PetscReal[], PetscReal[]);
592 PETSC_EXTERN PetscErrorCode PetscCDFGaussian1D(const PetscReal[], const PetscReal[], PetscReal[]);
593 PETSC_EXTERN PetscErrorCode PetscPDFSampleGaussian1D(const PetscReal[], const PetscReal[], PetscReal[]);
594 PETSC_EXTERN PetscErrorCode PetscPDFGaussian2D(const PetscReal[], const PetscReal[], PetscReal[]);
595 PETSC_EXTERN PetscErrorCode PetscPDFSampleGaussian2D(const PetscReal[], const PetscReal[], PetscReal[]);
596 PETSC_EXTERN PetscErrorCode PetscPDFGaussian3D(const PetscReal[], const PetscReal[], PetscReal[]);
597 PETSC_EXTERN PetscErrorCode PetscPDFSampleGaussian3D(const PetscReal[], const PetscReal[], PetscReal[]);
598 PETSC_EXTERN PetscErrorCode PetscPDFConstant1D(const PetscReal[], const PetscReal[], PetscReal[]);
599 PETSC_EXTERN PetscErrorCode PetscCDFConstant1D(const PetscReal[], const PetscReal[], PetscReal[]);
600 PETSC_EXTERN PetscErrorCode PetscPDFSampleConstant1D(const PetscReal[], const PetscReal[], PetscReal[]);
601 PETSC_EXTERN PetscErrorCode PetscPDFConstant2D(const PetscReal[], const PetscReal[], PetscReal[]);
602 PETSC_EXTERN PetscErrorCode PetscCDFConstant2D(const PetscReal[], const PetscReal[], PetscReal[]);
603 PETSC_EXTERN PetscErrorCode PetscPDFSampleConstant2D(const PetscReal[], const PetscReal[], PetscReal[]);
604 PETSC_EXTERN PetscErrorCode PetscPDFConstant3D(const PetscReal[], const PetscReal[], PetscReal[]);
605 PETSC_EXTERN PetscErrorCode PetscCDFConstant3D(const PetscReal[], const PetscReal[], PetscReal[]);
606 PETSC_EXTERN PetscErrorCode PetscPDFSampleConstant3D(const PetscReal[], const PetscReal[], PetscReal[]);
607 PETSC_EXTERN PetscErrorCode PetscProbCreateFromOptions(PetscInt, const char[], const char[], PetscProbFunc *, PetscProbFunc *, PetscProbFunc *);
608 
609 #include <petscvec.h>
610 
611 PETSC_EXTERN PetscErrorCode PetscProbComputeKSStatistic(Vec, PetscProbFunc, PetscReal *);
612