xref: /libCEED/examples/petsc/qfunctions/bps/bp4sphere.h (revision 423d854df121c192e1d9e4962fbebdb36fe7ec33)
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 /// libCEED QFunctions for mass operator example for a vector field on the sphere using PETSc
19 
20 #ifndef bp4sphere_h
21 #define bp4sphere_h
22 
23 #ifndef __CUDACC__
24 #  include <math.h>
25 #endif
26 
27 // *****************************************************************************
28 // This QFunction sets up the rhs and true solution for the problem
29 // *****************************************************************************
30 
31 // -----------------------------------------------------------------------------
32 CEED_QFUNCTION(SetupDiffRhs3)(void *ctx, const CeedInt Q,
33                              const CeedScalar *const *in,
34                              CeedScalar *const *out) {
35   // Inputs
36   const CeedScalar *X = in[0], *qdata = in[1];
37   // Outputs
38   CeedScalar *true_soln = out[0], *rhs = out[1];
39 
40   // Context
41   const CeedScalar *context = (const CeedScalar*)ctx;
42   const CeedScalar R        = context[0];
43 
44   // Quadrature Point Loop
45   CeedPragmaSIMD
46   for (CeedInt i=0; i<Q; i++) {
47     // Read global Cartesian coordinates
48     CeedScalar x = X[i+Q*0], y = X[i+Q*1], z = X[i+Q*2];
49     // Normalize quadrature point coordinates to sphere
50     CeedScalar rad = sqrt(x*x + y*y + z*z);
51     x *= R / rad;
52     y *= R / rad;
53     z *= R / rad;
54     // Compute latitude and longitude
55     const CeedScalar theta  = asin(z / R); // latitude
56     const CeedScalar lambda = atan2(y, x); // longitude
57 
58     // Use absolute value of latitute for true solution
59     // Component 1
60     true_soln[i+0*Q] = sin(lambda) * cos(theta);
61     // Component 2
62     true_soln[i+1*Q] = 2 * true_soln[i+0*Q];
63     // Component 3
64     true_soln[i+2*Q] = 3 * true_soln[i+0*Q];
65 
66     // Component 1
67     rhs[i+0*Q] = qdata[i+Q*0] * 2 * sin(lambda)*cos(theta) / (R*R);
68     // Component 2
69     rhs[i+1*Q] = 2 * rhs[i+0*Q];
70     // Component 3
71     rhs[i+2*Q] = 3 * rhs[i+0*Q];
72   } // End of Quadrature Point Loop
73 
74   return 0;
75 }
76 
77 // *****************************************************************************
78 // This QFunction applies the diffusion operator for a vector field of 3 components.
79 //
80 // Inputs:
81 //   ug     - Input vector Jacobian at quadrature points
82 //   qdata  - Geometric factors
83 //
84 // Output:
85 //   vJ     - Output vector (test functions) Jacobian at quadrature points
86 //
87 // *****************************************************************************
88 
89 // -----------------------------------------------------------------------------
90 CEED_QFUNCTION(Diff3)(void *ctx, const CeedInt Q,
91                       const CeedScalar *const *in, CeedScalar *const *out) {
92   const CeedScalar *ug = in[0], *qdata = in[1];
93   CeedScalar *vJ = out[0];
94 
95   // Quadrature Point Loop
96   CeedPragmaSIMD
97   for (CeedInt i=0; i<Q; i++) {
98     // Read spatial derivatives of u
99     const CeedScalar uJ[3][2]        = {{ug[i+(0+0*3)*Q],
100                                          ug[i+(0+1*3)*Q]},
101                                         {ug[i+(1+0*3)*Q],
102                                          ug[i+(1+1*3)*Q]},
103                                         {ug[i+(2+0*3)*Q],
104                                          ug[i+(2+1*3)*Q]}
105                                        };
106     // Read qdata
107     const CeedScalar wdetJ           =   qdata[i+Q*0];
108     // -- Grad-to-Grad qdata
109     // ---- dXdx_j,k * dXdx_k,j
110     const CeedScalar dXdxdXdxT[2][2] = {{qdata[i+Q*1],
111                                          qdata[i+Q*3]},
112                                         {qdata[i+Q*3],
113                                          qdata[i+Q*2]}
114                                        };
115 
116     for (int k=0; k<3; k++) // k = component
117       for (int j=0; j<2; j++) // j = direction of vg
118         vJ[i+(k+j*3)*Q] = wdetJ * (uJ[k][0] * dXdxdXdxT[0][j] +
119                                    uJ[k][1] * dXdxdXdxT[1][j]);
120 
121   } // End of Quadrature Point Loop
122 
123   return 0;
124 }
125 // -----------------------------------------------------------------------------
126 
127 #endif // bp4sphere_h
128