xref: /honee/qfunctions/setupgeo_helpers.h (revision f79b7f20ee7a2d310fc65d546f69afbf5e560555)
1 // Copyright (c) 2017-2024, Lawrence Livermore National Security, LLC and other CEED contributors.
2 // All Rights Reserved. See the top-level LICENSE and NOTICE files for details.
3 //
4 // SPDX-License-Identifier: BSD-2-Clause
5 //
6 // This file is part of CEED:  http://github.com/ceed
7 
8 /// @file
9 /// Geometric factors (3D) for Navier-Stokes example using PETSc
10 #pragma once
11 
12 #include <ceed.h>
13 #include <math.h>
14 
15 #include "utils.h"
16 
17 /**
18  * @brief Calculate dXdx from dxdX for 3D elements
19  *
20  * Reference (parent) coordinates: X
21  * Physical (current) coordinates: x
22  * Change of coordinate matrix: dxdX_{i,j} = x_{i,j} (indicial notation)
23  * Inverse of change of coordinate matrix: dXdx_{i,j} = (detJ^-1) * X_{i,j}
24  *
25  * Determinant of Jacobian:
26  *   detJ = J11*A11 + J21*A12 + J31*A13
27  *     Jij = Jacobian entry ij
28  *     Aij = Adjugate ij
29  *
30  * Inverse of Jacobian:
31  *   dXdx_i,j = Aij / detJ
32  *
33  * @param[in]  Q        Number of quadrature points
34  * @param[in]  i        Current quadrature point
35  * @param[in]  dxdX_q   Mapping Jacobian (gradient of the coordinate space)
36  * @param[out] dXdx     Inverse of mapping Jacobian at quadrature point i
37  * @param[out] detJ_ptr Determinate of the Jacobian, may be NULL is not desired
38  */
39 CEED_QFUNCTION_HELPER void InvertMappingJacobian_3D(CeedInt Q, CeedInt i, const CeedScalar (*dxdX_q)[3][CEED_Q_VLA], CeedScalar dXdx[3][3],
40                                                     CeedScalar *detJ_ptr) {
41   const CeedScalar dxdX_11 = dxdX_q[0][0][i];
42   const CeedScalar dxdX_21 = dxdX_q[0][1][i];
43   const CeedScalar dxdX_31 = dxdX_q[0][2][i];
44   const CeedScalar dxdX_12 = dxdX_q[1][0][i];
45   const CeedScalar dxdX_22 = dxdX_q[1][1][i];
46   const CeedScalar dxdX_32 = dxdX_q[1][2][i];
47   const CeedScalar dxdX_13 = dxdX_q[2][0][i];
48   const CeedScalar dxdX_23 = dxdX_q[2][1][i];
49   const CeedScalar dxdX_33 = dxdX_q[2][2][i];
50   const CeedScalar A11     = dxdX_22 * dxdX_33 - dxdX_23 * dxdX_32;
51   const CeedScalar A12     = dxdX_13 * dxdX_32 - dxdX_12 * dxdX_33;
52   const CeedScalar A13     = dxdX_12 * dxdX_23 - dxdX_13 * dxdX_22;
53   const CeedScalar A21     = dxdX_23 * dxdX_31 - dxdX_21 * dxdX_33;
54   const CeedScalar A22     = dxdX_11 * dxdX_33 - dxdX_13 * dxdX_31;
55   const CeedScalar A23     = dxdX_13 * dxdX_21 - dxdX_11 * dxdX_23;
56   const CeedScalar A31     = dxdX_21 * dxdX_32 - dxdX_22 * dxdX_31;
57   const CeedScalar A32     = dxdX_12 * dxdX_31 - dxdX_11 * dxdX_32;
58   const CeedScalar A33     = dxdX_11 * dxdX_22 - dxdX_12 * dxdX_21;
59   const CeedScalar detJ    = dxdX_11 * A11 + dxdX_21 * A12 + dxdX_31 * A13;
60 
61   dXdx[0][0] = A11 / detJ;
62   dXdx[0][1] = A12 / detJ;
63   dXdx[0][2] = A13 / detJ;
64   dXdx[1][0] = A21 / detJ;
65   dXdx[1][1] = A22 / detJ;
66   dXdx[1][2] = A23 / detJ;
67   dXdx[2][0] = A31 / detJ;
68   dXdx[2][1] = A32 / detJ;
69   dXdx[2][2] = A33 / detJ;
70   if (detJ_ptr) *detJ_ptr = detJ;
71 }
72 
73 /**
74  * @brief Calculate dXdx from dxdX for 3D elements
75  *
76  * Reference (parent) coordinates: X
77  * Physical (current) coordinates: x
78  * Change of coordinate matrix: dxdX_{i,j} = x_{i,j} (indicial notation)
79  * Inverse of change of coordinate matrix: dXdx_{i,j} = (detJ^-1) * X_{i,j}
80  *
81  * Determinant of Jacobian:
82  *   detJ = J11*A11 + J21*A12 + J31*A13
83  *     Jij = Jacobian entry ij
84  *     Aij = Adjugate ij
85  *
86  * Inverse of Jacobian:
87  *   dXdx_i,j = Aij / detJ
88  *
89  * @param[in]  Q        Number of quadrature points
90  * @param[in]  i        Current quadrature point
91  * @param[in]  dxdX_q   Mapping Jacobian (gradient of the coordinate space)
92  * @param[out] dXdx     Inverse of mapping Jacobian at quadrature point i
93  * @param[out] detJ_ptr Determinate of the Jacobian, may be NULL is not desired
94  */
95 CEED_QFUNCTION_HELPER void InvertMappingJacobian_2D(CeedInt Q, CeedInt i, const CeedScalar (*dxdX_q)[2][CEED_Q_VLA], CeedScalar dXdx[2][2],
96                                                     CeedScalar *detJ_ptr) {
97   const CeedScalar dxdX_11 = dxdX_q[0][0][i];
98   const CeedScalar dxdX_21 = dxdX_q[0][1][i];
99   const CeedScalar dxdX_12 = dxdX_q[1][0][i];
100   const CeedScalar dxdX_22 = dxdX_q[1][1][i];
101   const CeedScalar detJ    = dxdX_11 * dxdX_22 - dxdX_21 * dxdX_12;
102 
103   dXdx[0][0] = dxdX_22 / detJ;
104   dXdx[0][1] = -dxdX_12 / detJ;
105   dXdx[1][0] = -dxdX_21 / detJ;
106   dXdx[1][1] = dxdX_11 / detJ;
107   if (detJ_ptr) *detJ_ptr = detJ;
108 }
109 
110 /**
111  * @brief Calculate face element's normal vector from dxdX
112  *
113  * Reference (parent) 2D coordinates: X
114  * Physical (current) 3D coordinates: x
115  * Change of coordinate matrix:
116  *   dxdX_{i,j} = dx_i/dX_j (indicial notation) [3 * 2]
117  * Inverse change of coordinate matrix:
118  *   dXdx_{i,j} = dX_i/dx_j (indicial notation) [2 * 3]
119  *
120  * (J1,J2,J3) is given by the cross product of the columns of dxdX_{i,j}
121  *
122  * detJb is the magnitude of (J1,J2,J3)
123  *
124  * Normal vector = (J1,J2,J3) / detJb
125  *
126  * @param[in]  Q        Number of quadrature points
127  * @param[in]  i        Current quadrature point
128  * @param[in]  dxdX_q   Mapping Jacobian (gradient of the coordinate space)
129  * @param[out] normal   Inverse of mapping Jacobian at quadrature point i
130  * @param[out] detJ_ptr Determinate of the Jacobian, may be NULL is not desired
131  */
132 CEED_QFUNCTION_HELPER void NormalVectorFromdxdX_3D(CeedInt Q, CeedInt i, const CeedScalar (*dxdX_q)[3][CEED_Q_VLA], CeedScalar normal[3],
133                                                    CeedScalar *detJ_ptr) {
134   const CeedScalar dxdX[3][2] = {
135       {dxdX_q[0][0][i], dxdX_q[1][0][i]},
136       {dxdX_q[0][1][i], dxdX_q[1][1][i]},
137       {dxdX_q[0][2][i], dxdX_q[1][2][i]}
138   };
139   // J1, J2, and J3 are given by the cross product of the columns of dxdX
140   const CeedScalar J1 = dxdX[1][0] * dxdX[2][1] - dxdX[2][0] * dxdX[1][1];
141   const CeedScalar J2 = dxdX[2][0] * dxdX[0][1] - dxdX[0][0] * dxdX[2][1];
142   const CeedScalar J3 = dxdX[0][0] * dxdX[1][1] - dxdX[1][0] * dxdX[0][1];
143 
144   const CeedScalar detJ = sqrt(J1 * J1 + J2 * J2 + J3 * J3);
145 
146   normal[0] = J1 / detJ;
147   normal[1] = J2 / detJ;
148   normal[2] = J3 / detJ;
149   if (detJ_ptr) *detJ_ptr = detJ;
150 }
151 
152 /**
153  * This QFunction sets up the geometric factor required for integration when reference coordinates are in 1D and the physical coordinates are in 2D
154  *
155  * Reference (parent) 1D coordinates: X
156  * Physical (current) 2D coordinates: x
157  * Change of coordinate vector:
158  *           J1 = dx_1/dX
159  *           J2 = dx_2/dX
160  *
161  * detJb is the magnitude of (J1,J2)
162  *
163  * We require the determinant of the Jacobian to properly compute integrals of the form: int( u v )
164  *
165  * Normal vector is given by the cross product of (J1,J2)/detJ and ẑ
166  *
167  * @param[in]  Q        Number of quadrature points
168  * @param[in]  i        Current quadrature point
169  * @param[in]  dxdX_q   Mapping Jacobian (gradient of the coordinate space)
170  * @param[out] normal   Inverse of mapping Jacobian at quadrature point i
171  * @param[out] detJ_ptr Determinate of the Jacobian, may be NULL is not desired
172  */
173 CEED_QFUNCTION_HELPER void NormalVectorFromdxdX_2D(CeedInt Q, CeedInt i, const CeedScalar (*dxdX_q)[CEED_Q_VLA], CeedScalar normal[2],
174                                                    CeedScalar *detJ_ptr) {
175   const CeedScalar J1 = dxdX_q[0][i];
176   const CeedScalar J2 = dxdX_q[1][i];
177 
178   CeedScalar detJb = sqrt(J1 * J1 + J2 * J2);
179   normal[0]        = J2 / detJb;
180   normal[1]        = -J1 / detJb;
181   if (detJ_ptr) *detJ_ptr = detJb;
182 }
183 
184 /**
185  * @brief Calculate inverse of mapping Jacobian, (dxdX)^-1
186  *
187  * Reference (parent) 2D coordinates: X
188  * Physical (current) 3D coordinates: x
189  * Change of coordinate matrix:
190  *   dxdX_{i,j} = dx_i/dX_j (indicial notation) [3 * 2]
191  * Inverse change of coordinate matrix:
192  *   dXdx_{i,j} = dX_i/dx_j (indicial notation) [2 * 3]
193  *
194  * dXdx is calculated via Moore–Penrose inverse:
195  *
196  *   dX_i/dx_j = (dxdX^T dxdX)^(-1) dxdX
197  *             = (dx_l/dX_i * dx_l/dX_k)^(-1) dx_j/dX_k
198  *
199  * @param[in]  Q      Number of quadrature points
200  * @param[in]  i      Current quadrature point
201  * @param[in]  dxdX_q Mapping Jacobian (gradient of the coordinate space)
202  * @param[out] dXdx   Inverse of mapping Jacobian at quadrature point i
203  */
204 CEED_QFUNCTION_HELPER void InvertBoundaryMappingJacobian_3D(CeedInt Q, CeedInt i, const CeedScalar (*dxdX_q)[3][CEED_Q_VLA], CeedScalar dXdx[2][3]) {
205   const CeedScalar dxdX[3][2] = {
206       {dxdX_q[0][0][i], dxdX_q[1][0][i]},
207       {dxdX_q[0][1][i], dxdX_q[1][1][i]},
208       {dxdX_q[0][2][i], dxdX_q[1][2][i]}
209   };
210 
211   // dxdX_k,j * dxdX_j,k
212   CeedScalar dxdXTdxdX[2][2] = {{0.}};
213   for (CeedInt j = 0; j < 2; j++) {
214     for (CeedInt k = 0; k < 2; k++) {
215       for (CeedInt l = 0; l < 3; l++) dxdXTdxdX[j][k] += dxdX[l][j] * dxdX[l][k];
216     }
217   }
218 
219   const CeedScalar detdxdXTdxdX = dxdXTdxdX[0][0] * dxdXTdxdX[1][1] - dxdXTdxdX[1][0] * dxdXTdxdX[0][1];
220 
221   // Compute inverse of dxdXTdxdX
222   CeedScalar dxdXTdxdX_inv[2][2];
223   dxdXTdxdX_inv[0][0] = dxdXTdxdX[1][1] / detdxdXTdxdX;
224   dxdXTdxdX_inv[0][1] = -dxdXTdxdX[0][1] / detdxdXTdxdX;
225   dxdXTdxdX_inv[1][0] = -dxdXTdxdX[1][0] / detdxdXTdxdX;
226   dxdXTdxdX_inv[1][1] = dxdXTdxdX[0][0] / detdxdXTdxdX;
227 
228   // Compute dXdx from dxdXTdxdX^-1 and dxdX
229   for (CeedInt j = 0; j < 2; j++) {
230     for (CeedInt k = 0; k < 3; k++) {
231       dXdx[j][k] = 0;
232       for (CeedInt l = 0; l < 2; l++) dXdx[j][k] += dxdXTdxdX_inv[l][j] * dxdX[k][l];
233     }
234   }
235 }
236