xref: /libCEED/include/ceed.h (revision 26cf1b823287f0610ab7e6cd21f931a86083051c)
1 /// Copyright (c) 2017, Lawrence Livermore National Security, LLC. Produced at
2 /// the Lawrence Livermore National Laboratory. LLNL-CODE-734707. All Rights
3 /// reserved. See files LICENSE and NOTICE for details.
4 ///
5 /// This file is part of CEED, a collection of benchmarks, miniapps, software
6 /// libraries and APIs for efficient high-order finite element and spectral
7 /// element discretizations for exascale applications. For more information and
8 /// source code availability see http://github.com/ceed.
9 ///
10 /// The CEED research is supported by the Exascale Computing Project 17-SC-20-SC,
11 /// a collaborative effort of two U.S. Department of Energy organizations (Office
12 /// of Science and the National Nuclear Security Administration) responsible for
13 /// the planning and preparation of a capable exascale ecosystem, including
14 /// software, applications, hardware, advanced system engineering and early
15 /// testbed platforms, in support of the nation's exascale computing imperative.
16 
17 /// @file
18 /// Public header for user and utility components of libCEED
19 #ifndef _ceed_h
20 #define _ceed_h
21 
22 /// @defgroup Ceed Ceed: core components
23 /// @defgroup CeedVector CeedVector: storing and manipulating vectors
24 /// @defgroup CeedElemRestriction CeedElemRestriction: restriction from local vectors to elements
25 /// @defgroup CeedBasis CeedBasis: fully discrete finite element-like objects
26 /// @defgroup CeedQFunction CeedQFunction: independent operations at quadrature points
27 /// @defgroup CeedOperator CeedOperator: composed FE-type operations on vectors
28 ///
29 /// @page FunctionCategories libCEED: Types of Functions
30 ///    libCEED provides three different header files depending upon the type of
31 ///    functions a user requires.
32 /// @section Utility Utility Functions
33 ///    These functions are intended general utilities that may be useful to
34 ///    libCEED developers and users. These functions can generally be found in
35 ///    "ceed.h".
36 /// @section User User Functions
37 ///    These functions are intended to be used by general users of libCEED
38 ///    and can generally be found in "ceed.h".
39 /// @section Backend Backend Developer Functions
40 ///    These functions are intended to be used by backend developers of
41 ///    libCEED and can generally be found in "ceed-backend.h".
42 /// @section Developer Library Developer Functions
43 ///    These functions are intended to be used by library developers of
44 ///    libCEED and can generally be found in "ceed-impl.h".
45 
46 /**
47   CEED_EXTERN is used in this header to denote all publicly visible symbols.
48 
49   No other file should declare publicly visible symbols, thus it should never be
50   used outside ceed.h.
51  */
52 #ifdef __cplusplus
53 #  define CEED_EXTERN extern "C"
54 #else
55 #  define CEED_EXTERN extern
56 #endif
57 
58 /**
59   @ingroup CeedQFunction
60   This macro populates the correct function annotations for User QFunction
61     source for code generation backends or populates default values for CPU
62     backends.
63 **/
64 #ifndef CEED_QFUNCTION
65 #define CEED_QFUNCTION(name) \
66   static const char name ## _loc[] = __FILE__ ":" #name;        \
67   static int name
68 #endif
69 
70 /**
71   @ingroup CeedQFunction
72   Using VLA syntax to reshape User QFunction inputs and outputs can make
73     user code more readable. VLA is a C99 feature that is not supported by
74     the C++ dialect used by CUDA. This macro allows users to use the VLA
75     syntax with the CUDA backends.
76 **/
77 #ifndef CEED_Q_VLA
78 #  define CEED_Q_VLA Q
79 #endif
80 
81 /**
82   @ingroup Ceed
83   This macro provides the appropriate SIMD Pragma for the compilation
84     environment. Code generation backends may redefine this macro, as needed.
85 **/
86 #ifndef CeedPragmaSIMD
87 #  if defined(__INTEL_COMPILER)
88 #    define CeedPragmaSIMD _Pragma("vector")
89 // Cannot use Intel pragma ivdep because it miscompiles unpacking symmetric tensors, as in
90 // Poisson2DApply, where the SIMD loop body contains temporaries such as the following.
91 //
92 //     const CeedScalar dXdxdXdxT[2][2] = {{qd[i+0*Q], qd[i+2*Q]},
93 //                                         {qd[i+2*Q], qd[i+1*Q]}};
94 //     for (int j=0; j<2; j++)
95 //        vg[i+j*Q] = (du[0] * dXdxdXdxT[0][j] + du[1] * dXdxdXdxT[1][j]);
96 //
97 // Miscompilation with pragma ivdep observed with icc (ICC) 19.0.5.281 20190815
98 // at -O2 and above.
99 #  elif defined(__GNUC__) && __GNUC__ >= 5
100 #    define CeedPragmaSIMD _Pragma("GCC ivdep")
101 #  elif defined(_OPENMP) && _OPENMP >= 201307 // OpenMP-4.0 (July, 2013)
102 #    define CeedPragmaSIMD _Pragma("omp simd")
103 #  else
104 #    define CeedPragmaSIMD
105 #  endif
106 #endif
107 
108 #include <assert.h>
109 #include <stdint.h>
110 #include <stddef.h>
111 #include <stdarg.h>
112 #include <stdio.h>
113 #include <stdbool.h>
114 
115 /// Integer type, used for indexing
116 /// @ingroup Ceed
117 typedef int32_t CeedInt;
118 /// Scalar (floating point) type
119 /// @ingroup Ceed
120 typedef double CeedScalar;
121 
122 /// Library context created by CeedInit()
123 /// @ingroup CeedUser
124 typedef struct Ceed_private *Ceed;
125 /// Non-blocking Ceed interfaces return a CeedRequest.
126 /// To perform an operation immediately, pass \ref CEED_REQUEST_IMMEDIATE instead.
127 /// @ingroup CeedUser
128 typedef struct CeedRequest_private *CeedRequest;
129 /// Handle for vectors over the field \ref CeedScalar
130 /// @ingroup CeedVectorUser
131 typedef struct CeedVector_private *CeedVector;
132 /// Handle for object describing restriction to elements
133 /// @ingroup CeedElemRestrictionUser
134 typedef struct CeedElemRestriction_private *CeedElemRestriction;
135 /// Handle for object describing discrete finite element evaluations
136 /// @ingroup CeedBasisUser
137 typedef struct CeedBasis_private *CeedBasis;
138 /// Handle for object describing functions evaluated independently at quadrature points
139 /// @ingroup CeedQFunctionUser
140 typedef struct CeedQFunction_private *CeedQFunction;
141 /// Handle for object describing FE-type operators acting on vectors
142 ///
143 /// Given an element restriction \f$E\f$, basis evaluator \f$B\f$, and
144 ///   quadrature function\f$f\f$, a CeedOperator expresses operations of the form
145 ///   $$ E^T B^T f(B E u) $$
146 ///   acting on the vector \f$u\f$.
147 /// @ingroup CeedOperatorUser
148 typedef struct CeedOperator_private *CeedOperator;
149 
150 CEED_EXTERN int CeedInit(const char *resource, Ceed *ceed);
151 CEED_EXTERN int CeedGetResource(Ceed ceed, const char **resource);
152 CEED_EXTERN int CeedIsDeterministic(Ceed ceed, bool *isDeterministic);
153 CEED_EXTERN int CeedView(Ceed ceed, FILE *stream);
154 CEED_EXTERN int CeedDestroy(Ceed *ceed);
155 
156 CEED_EXTERN int CeedErrorImpl(Ceed, const char *, int, const char *, int,
157                               const char *, ...);
158 /// Raise an error on ceed object
159 ///
160 /// @param ceed Ceed library context or NULL
161 /// @param ecode Error code (int)
162 /// @param ... printf-style format string followed by arguments as needed
163 ///
164 /// @ingroup Ceed
165 /// @sa CeedSetErrorHandler()
166 #if defined(__clang__)
167 /// Use nonstandard ternary to convince the compiler/clang-tidy that this
168 /// function never returns zero.
169 #  define CeedError(ceed, ecode, ...)                                     \
170   (CeedErrorImpl((ceed), __FILE__, __LINE__, __func__, (ecode), __VA_ARGS__) ?: (ecode))
171 #else
172 #  define CeedError(ceed, ecode, ...)                                     \
173   CeedErrorImpl((ceed), __FILE__, __LINE__, __func__, (ecode), __VA_ARGS__) ?: (ecode)
174 #endif
175 
176 /// Ceed error handlers
177 CEED_EXTERN int CeedErrorReturn(Ceed, const char *, int, const char *, int,
178                                 const char *, va_list);
179 CEED_EXTERN int CeedErrorStore(Ceed, const char *, int, const char *, int,
180                                const char *, va_list);
181 CEED_EXTERN int CeedErrorAbort(Ceed, const char *, int, const char *, int,
182                                const char *, va_list);
183 CEED_EXTERN int CeedErrorExit(Ceed, const char *, int, const char *, int,
184                               const char *, va_list);
185 CEED_EXTERN int CeedSetErrorHandler(Ceed ceed,
186                                     int (*eh)(Ceed, const char *, int,
187                                         const char *, int, const char *,
188                                         va_list));
189 CEED_EXTERN int CeedGetErrorMessage(Ceed, const char **errmsg);
190 CEED_EXTERN int CeedResetErrorMessage(Ceed, const char **errmsg);
191 
192 /// Specify memory type
193 ///
194 /// Many Ceed interfaces take or return pointers to memory.  This enum is used to
195 /// specify where the memory being provided or requested must reside.
196 /// @ingroup Ceed
197 typedef enum {
198   /// Memory resides on the host
199   CEED_MEM_HOST,
200   /// Memory resides on a device (corresponding to \ref Ceed resource)
201   CEED_MEM_DEVICE,
202 } CeedMemType;
203 
204 CEED_EXTERN const char *const CeedMemTypes[];
205 
206 CEED_EXTERN int CeedGetPreferredMemType(Ceed ceed, CeedMemType *type);
207 
208 /// Conveys ownership status of arrays passed to Ceed interfaces.
209 /// @ingroup Ceed
210 typedef enum {
211   /// Implementation will copy the values and not store the passed pointer.
212   CEED_COPY_VALUES,
213   /// Implementation can use and modify the data provided by the user, but does
214   /// not take ownership.
215   CEED_USE_POINTER,
216   /// Implementation takes ownership of the pointer and will free using
217   /// CeedFree() when done using it.  The user should not assume that the
218   /// pointer remains valid after ownership has been transferred.  Note that
219   /// arrays allocated using C++ operator new or other allocators cannot
220   /// generally be freed using CeedFree().  CeedFree() is capable of freeing any
221   /// memory that can be freed using free(3).
222   CEED_OWN_POINTER,
223 } CeedCopyMode;
224 
225 /// Denotes type of vector norm to be computed
226 /// @ingroup CeedVector
227 typedef enum {
228   /// L_1 norm: sum_i |x_i|
229   CEED_NORM_1,
230   /// L_2 norm: sqrt(sum_i |x_i|^2)
231   CEED_NORM_2,
232   /// L_Infinity norm: max_i |x_i|
233   CEED_NORM_MAX,
234 } CeedNormType;
235 
236 CEED_EXTERN const char *const CeedCopyModes[];
237 
238 CEED_EXTERN int CeedVectorCreate(Ceed ceed, CeedInt len, CeedVector *vec);
239 CEED_EXTERN int CeedVectorSetArray(CeedVector vec, CeedMemType mtype,
240                                    CeedCopyMode cmode, CeedScalar *array);
241 CEED_EXTERN int CeedVectorSetValue(CeedVector vec, CeedScalar value);
242 CEED_EXTERN int CeedVectorSyncArray(CeedVector vec, CeedMemType mtype);
243 CEED_EXTERN int CeedVectorTakeArray(CeedVector vec, CeedMemType mtype,
244                                     CeedScalar **array);
245 CEED_EXTERN int CeedVectorGetArray(CeedVector vec, CeedMemType mtype,
246                                    CeedScalar **array);
247 CEED_EXTERN int CeedVectorGetArrayRead(CeedVector vec, CeedMemType mtype,
248                                        const CeedScalar **array);
249 CEED_EXTERN int CeedVectorRestoreArray(CeedVector vec, CeedScalar **array);
250 CEED_EXTERN int CeedVectorRestoreArrayRead(CeedVector vec,
251     const CeedScalar **array);
252 CEED_EXTERN int CeedVectorNorm(CeedVector vec, CeedNormType type,
253                                CeedScalar *norm);
254 CEED_EXTERN int CeedVectorView(CeedVector vec, const char *fpfmt, FILE *stream);
255 CEED_EXTERN int CeedVectorGetLength(CeedVector vec, CeedInt *length);
256 CEED_EXTERN int CeedVectorDestroy(CeedVector *vec);
257 
258 CEED_EXTERN CeedRequest *const CEED_REQUEST_IMMEDIATE;
259 CEED_EXTERN CeedRequest *const CEED_REQUEST_ORDERED;
260 CEED_EXTERN int CeedRequestWait(CeedRequest *req);
261 
262 /// Argument for CeedOperatorSetField that vector is collocated with
263 /// quadrature points, used with QFunction eval mode CEED_EVAL_NONE
264 /// or CEED_EVAL_INTERP only, not with CEED_EVAL_GRAD, CEED_EVAL_DIV,
265 /// or CEED_EVAL_CURL
266 /// @ingroup CeedBasis
267 CEED_EXTERN const CeedBasis CEED_BASIS_COLLOCATED;
268 
269 /// Argument for CeedOperatorSetField to use active input or output
270 /// @ingroup CeedVector
271 CEED_EXTERN const CeedVector CEED_VECTOR_ACTIVE;
272 
273 /// Argument for CeedOperatorSetField to use no vector, used with
274 /// qfunction input with eval mode CEED_EVAL_WEIGHT
275 /// @ingroup CeedVector
276 CEED_EXTERN const CeedVector CEED_VECTOR_NONE;
277 
278 /// Argument for CeedOperatorSetField to use no ElemRestriction, only used with
279 /// eval mode CEED_EVAL_WEIGHT.
280 /// @ingroup CeedElemRestriction
281 CEED_EXTERN const CeedElemRestriction CEED_ELEMRESTRICTION_NONE;
282 
283 /// Argument for CeedOperatorCreate that QFunction is not created by user.
284 /// Only used for QFunctions dqf and dqfT. If implemented, a backend may
285 /// attempt to provide the action of these QFunctions.
286 /// @ingroup CeedQFunction
287 CEED_EXTERN const CeedQFunction CEED_QFUNCTION_NONE;
288 
289 /// Denotes whether a linear transformation or its transpose should be applied
290 /// @ingroup CeedBasis
291 typedef enum {
292   /// Apply the linear transformation
293   CEED_NOTRANSPOSE,
294   /// Apply the transpose
295   CEED_TRANSPOSE
296 } CeedTransposeMode;
297 
298 CEED_EXTERN const char *const CeedTransposeModes[];
299 
300 /// Argument for CeedElemRestrictionCreateStrided that L-vector is in
301 /// the Ceed backend's preferred layout. This argument should only be used
302 /// with vectors created by a Ceed backend.
303 /// @ingroup CeedElemRestriction
304 CEED_EXTERN const CeedInt CEED_STRIDES_BACKEND[3];
305 
306 CEED_EXTERN int CeedElemRestrictionCreate(Ceed ceed, CeedInt nelem,
307     CeedInt elemsize, CeedInt ncomp, CeedInt compstride, CeedInt lsize,
308     CeedMemType mtype, CeedCopyMode cmode, const CeedInt *offsets,
309     CeedElemRestriction *rstr);
310 CEED_EXTERN int CeedElemRestrictionCreateStrided(Ceed ceed,
311     CeedInt nelem, CeedInt elemsize, CeedInt ncomp, CeedInt lsize,
312     const CeedInt strides[3], CeedElemRestriction *rstr);
313 CEED_EXTERN int CeedElemRestrictionCreateBlocked(Ceed ceed, CeedInt nelem,
314     CeedInt elemsize, CeedInt blksize, CeedInt ncomp, CeedInt compstride,
315     CeedInt lsize, CeedMemType mtype, CeedCopyMode cmode,
316     const CeedInt *offsets, CeedElemRestriction *rstr);
317 CEED_EXTERN int CeedElemRestrictionCreateBlockedStrided(Ceed ceed,
318     CeedInt nelem, CeedInt elemsize, CeedInt blksize, CeedInt ncomp,
319     CeedInt lsize, const CeedInt strides[3], CeedElemRestriction *rstr);
320 CEED_EXTERN int CeedElemRestrictionCreateVector(CeedElemRestriction rstr,
321     CeedVector *lvec, CeedVector *evec);
322 CEED_EXTERN int CeedElemRestrictionApply(CeedElemRestriction rstr,
323     CeedTransposeMode tmode, CeedVector u, CeedVector ru, CeedRequest *request);
324 CEED_EXTERN int CeedElemRestrictionApplyBlock(CeedElemRestriction rstr,
325     CeedInt block, CeedTransposeMode tmode, CeedVector u, CeedVector ru,
326     CeedRequest *request);
327 CEED_EXTERN int CeedElemRestrictionGetCompStride(CeedElemRestriction rstr,
328     CeedInt *compstride);
329 CEED_EXTERN int CeedElemRestrictionGetNumElements(CeedElemRestriction rstr,
330     CeedInt *numelem);
331 CEED_EXTERN int CeedElemRestrictionGetElementSize(CeedElemRestriction rstr,
332     CeedInt *elemsize);
333 CEED_EXTERN int CeedElemRestrictionGetLVectorSize(CeedElemRestriction rstr,
334     CeedInt *lsize);
335 CEED_EXTERN int CeedElemRestrictionGetNumComponents(CeedElemRestriction rstr,
336     CeedInt *numcomp);
337 CEED_EXTERN int CeedElemRestrictionGetNumBlocks(CeedElemRestriction rstr,
338     CeedInt *numblk);
339 CEED_EXTERN int CeedElemRestrictionGetBlockSize(CeedElemRestriction rstr,
340     CeedInt *blksize);
341 CEED_EXTERN int CeedElemRestrictionGetMultiplicity(CeedElemRestriction rstr,
342     CeedVector mult);
343 CEED_EXTERN int CeedElemRestrictionView(CeedElemRestriction rstr, FILE *stream);
344 CEED_EXTERN int CeedElemRestrictionDestroy(CeedElemRestriction *rstr);
345 
346 // The formalism here is that we have the structure
347 //  \int_\Omega v^T f_0(u, \nabla u, qdata) + (\nabla v)^T f_1(u, \nabla u, qdata)
348 // where gradients are with respect to the reference element.
349 
350 /// Basis evaluation mode
351 ///
352 /// Modes can be bitwise ORed when passing to most functions.
353 /// @ingroup CeedBasis
354 typedef enum {
355   /// Perform no evaluation (either because there is no data or it is already at
356   /// quadrature points)
357   CEED_EVAL_NONE   = 0,
358   /// Interpolate from nodes to quadrature points
359   CEED_EVAL_INTERP = 1,
360   /// Evaluate gradients at quadrature points from input in a nodal basis
361   CEED_EVAL_GRAD   = 2,
362   /// Evaluate divergence at quadrature points from input in a nodal basis
363   CEED_EVAL_DIV    = 4,
364   /// Evaluate curl at quadrature points from input in a nodal basis
365   CEED_EVAL_CURL   = 8,
366   /// Using no input, evaluate quadrature weights on the reference element
367   CEED_EVAL_WEIGHT = 16,
368 } CeedEvalMode;
369 
370 CEED_EXTERN const char *const CeedEvalModes[];
371 
372 /// Type of quadrature; also used for location of nodes
373 /// @ingroup CeedBasis
374 typedef enum {
375   /// Gauss-Legendre quadrature
376   CEED_GAUSS = 0,
377   /// Gauss-Legendre-Lobatto quadrature
378   CEED_GAUSS_LOBATTO = 1,
379 } CeedQuadMode;
380 
381 CEED_EXTERN const char *const CeedQuadModes[];
382 
383 /// Type of basis shape to create non-tensor H1 element basis
384 ///
385 /// Dimension can be extracted with bitwise AND
386 /// (CeedElemTopology & 2**(dim + 2)) == TRUE
387 /// @ingroup CeedBasis
388 typedef enum {
389   /// Line
390   CEED_LINE = 1 << 16 | 0,
391   /// Triangle - 2D shape
392   CEED_TRIANGLE = 2 << 16 | 1,
393   /// Quadralateral - 2D shape
394   CEED_QUAD = 2 << 16 | 2,
395   /// Tetrahedron - 3D shape
396   CEED_TET = 3 << 16 | 3,
397   /// Pyramid - 3D shape
398   CEED_PYRAMID = 3 << 16 | 4,
399   /// Prism - 3D shape
400   CEED_PRISM = 3 << 16 | 5,
401   /// Hexehedron - 3D shape
402   CEED_HEX = 3 << 16 | 6,
403 } CeedElemTopology;
404 
405 CEED_EXTERN const char *const CeedElemTopologies[];
406 
407 CEED_EXTERN int CeedBasisCreateTensorH1Lagrange(Ceed ceed, CeedInt dim,
408     CeedInt ncomp, CeedInt P, CeedInt Q, CeedQuadMode qmode, CeedBasis *basis);
409 CEED_EXTERN int CeedBasisCreateTensorH1(Ceed ceed, CeedInt dim, CeedInt ncomp,
410                                         CeedInt P1d, CeedInt Q1d,
411                                         const CeedScalar *interp1d,
412                                         const CeedScalar *grad1d,
413                                         const CeedScalar *qref1d,
414                                         const CeedScalar *qweight1d,
415                                         CeedBasis *basis);
416 CEED_EXTERN int CeedBasisCreateH1(Ceed ceed, CeedElemTopology topo,
417                                   CeedInt ncomp,
418                                   CeedInt nnodes, CeedInt nqpts,
419                                   const CeedScalar *interp,
420                                   const CeedScalar *grad,
421                                   const CeedScalar *qref,
422                                   const CeedScalar *qweight, CeedBasis *basis);
423 CEED_EXTERN int CeedBasisView(CeedBasis basis, FILE *stream);
424 CEED_EXTERN int CeedBasisApply(CeedBasis basis, CeedInt nelem,
425                                CeedTransposeMode tmode,
426                                CeedEvalMode emode, CeedVector u, CeedVector v);
427 CEED_EXTERN int CeedBasisGetDimension(CeedBasis basis, CeedInt *dim);
428 CEED_EXTERN int CeedBasisGetNumComponents(CeedBasis basis, CeedInt *numcomp);
429 CEED_EXTERN int CeedBasisGetNumNodes(CeedBasis basis, CeedInt *P);
430 CEED_EXTERN int CeedBasisGetNumNodes1D(CeedBasis basis, CeedInt *P1d);
431 CEED_EXTERN int CeedBasisGetNumQuadraturePoints(CeedBasis basis, CeedInt *Q);
432 CEED_EXTERN int CeedBasisGetNumQuadraturePoints1D(CeedBasis basis,
433     CeedInt *Q1d);
434 CEED_EXTERN int CeedBasisGetQRef(CeedBasis basis, const CeedScalar **qref);
435 CEED_EXTERN int CeedBasisGetQWeights(CeedBasis basis,
436                                      const CeedScalar **qweight);
437 CEED_EXTERN int CeedBasisGetInterp(CeedBasis basis, const CeedScalar **interp);
438 CEED_EXTERN int CeedBasisGetInterp1D(CeedBasis basis,
439                                      const CeedScalar **interp1d);
440 CEED_EXTERN int CeedBasisGetGrad(CeedBasis basis, const CeedScalar **grad);
441 CEED_EXTERN int CeedBasisGetGrad1D(CeedBasis basis, const CeedScalar **grad1d);
442 CEED_EXTERN int CeedBasisDestroy(CeedBasis *basis);
443 
444 CEED_EXTERN int CeedGaussQuadrature(CeedInt Q, CeedScalar *qref1d,
445                                     CeedScalar *qweight1d);
446 CEED_EXTERN int CeedLobattoQuadrature(CeedInt Q, CeedScalar *qref1d,
447                                       CeedScalar *qweight1d);
448 CEED_EXTERN int CeedQRFactorization(Ceed ceed, CeedScalar *mat, CeedScalar *tau,
449                                     CeedInt m, CeedInt n);
450 CEED_EXTERN int CeedSymmetricSchurDecomposition(Ceed ceed, CeedScalar *mat,
451     CeedScalar *lambda, CeedInt n);
452 CEED_EXTERN int CeedSimultaneousDiagonalization(Ceed ceed, CeedScalar *matA,
453     CeedScalar *matB, CeedScalar *x, CeedScalar *lambda, CeedInt n);
454 
455 /** Handle for the object describing the user CeedQFunction
456 
457  @param ctx user-defined context set using CeedQFunctionSetContext() or NULL
458 
459  @param Q   number of quadrature points at which to evaluate
460 
461  @param in  array of pointers to each input argument in the order provided
462               by the user in CeedQFunctionAddInput().  Each array has shape
463               `[dim, ncomp, Q]` where `dim` is the geometric dimension for
464               \ref CEED_EVAL_GRAD (`dim=1` for \ref CEED_EVAL_INTERP) and
465               `ncomp` is the number of field components (`ncomp=1` for
466               scalar fields).  This results in indexing the `i`th input at
467               quadrature point `j` as `in[i][(d*ncomp + c)*Q + j]`.
468 
469  @param out array of pointers to each output array in the order provided
470               using CeedQFunctionAddOutput().  The shapes are as above for
471               \a in.
472 
473  @return An error code: 0 - success, otherwise - failure
474 
475  @ingroup CeedQFunction
476 **/
477 typedef int (*CeedQFunctionUser)(void *ctx, const CeedInt Q,
478                                  const CeedScalar *const *in,
479                                  CeedScalar *const *out);
480 
481 CEED_EXTERN int CeedQFunctionCreateInterior(Ceed ceed, CeedInt vlength,
482     CeedQFunctionUser f, const char *source, CeedQFunction *qf);
483 CEED_EXTERN int CeedQFunctionCreateInteriorByName(Ceed ceed, const char *name,
484     CeedQFunction *qf);
485 CEED_EXTERN int CeedQFunctionCreateIdentity(Ceed ceed, CeedInt size,
486     CeedEvalMode inmode, CeedEvalMode outmode, CeedQFunction *qf);
487 CEED_EXTERN int CeedQFunctionAddInput(CeedQFunction qf, const char *fieldname,
488                                       CeedInt size, CeedEvalMode emode);
489 CEED_EXTERN int CeedQFunctionAddOutput(CeedQFunction qf, const char *fieldname,
490                                        CeedInt size, CeedEvalMode emode);
491 CEED_EXTERN int CeedQFunctionSetContext(CeedQFunction qf, void *ctx,
492                                         size_t ctxsize);
493 CEED_EXTERN int CeedQFunctionView(CeedQFunction qf, FILE *stream);
494 CEED_EXTERN int CeedQFunctionApply(CeedQFunction qf, CeedInt Q,
495                                    CeedVector *u, CeedVector *v);
496 CEED_EXTERN int CeedQFunctionDestroy(CeedQFunction *qf);
497 
498 CEED_EXTERN int CeedOperatorCreate(Ceed ceed, CeedQFunction qf,
499                                    CeedQFunction dqf, CeedQFunction dqfT,
500                                    CeedOperator *op);
501 CEED_EXTERN int CeedCompositeOperatorCreate(Ceed ceed, CeedOperator *op);
502 CEED_EXTERN int CeedOperatorSetField(CeedOperator op, const char *fieldname,
503                                      CeedElemRestriction r, CeedBasis b,
504                                      CeedVector v);
505 CEED_EXTERN int CeedCompositeOperatorAddSub(CeedOperator compositeop,
506     CeedOperator subop);
507 CEED_EXTERN int CeedOperatorLinearAssembleQFunction(CeedOperator op,
508     CeedVector *assembled, CeedElemRestriction *rstr, CeedRequest *request);
509 CEED_EXTERN int CeedOperatorLinearAssembleDiagonal(CeedOperator op,
510     CeedVector assembled, CeedRequest *request);
511 CEED_EXTERN int CeedOperatorLinearAssembleAddDiagonal(CeedOperator op,
512     CeedVector assembled, CeedRequest *request);
513 CEED_EXTERN int CeedOperatorLinearAssemblePointBlockDiagonal(CeedOperator op,
514     CeedVector assembled, CeedRequest *request);
515 CEED_EXTERN int CeedOperatorLinearAssembleAddPointBlockDiagonal(CeedOperator op,
516     CeedVector assembled, CeedRequest *request);
517 CEED_EXTERN int CeedOperatorCreateFDMElementInverse(CeedOperator op,
518     CeedOperator *fdminv, CeedRequest *request);
519 CEED_EXTERN int CeedOperatorView(CeedOperator op, FILE *stream);
520 CEED_EXTERN int CeedOperatorApply(CeedOperator op, CeedVector in,
521                                   CeedVector out, CeedRequest *request);
522 CEED_EXTERN int CeedOperatorApplyAdd(CeedOperator op, CeedVector in,
523                                      CeedVector out, CeedRequest *request);
524 CEED_EXTERN int CeedOperatorDestroy(CeedOperator *op);
525 
526 /**
527   @brief Return integer power
528 
529   @param[in] base   The base to exponentiate
530   @param[in] power  The power to raise the base to
531 
532   @return base^power
533 
534   @ref Utility
535 **/
536 static inline CeedInt CeedIntPow(CeedInt base, CeedInt power) {
537   CeedInt result = 1;
538   while (power) {
539     if (power & 1) result *= base;
540     power >>= 1;
541     base *= base;
542   }
543   return result;
544 }
545 
546 /**
547   @brief Return minimum of two integers
548 
549   @param[in] a  The first integer to compare
550   @param[in] b  The second integer to compare
551 
552   @return The minimum of the two integers
553 
554   @ref Utility
555 **/
556 static inline CeedInt CeedIntMin(CeedInt a, CeedInt b) { return a < b ? a : b; }
557 
558 #endif
559