xref: /honee/qfunctions/setupgeo_helpers.h (revision b78d7c7d152a2530c4ff7c4fb0143fe9be02cbec)
1 // SPDX-FileCopyrightText: Copyright (c) 2017-2024, HONEE contributors.
2 // SPDX-License-Identifier: Apache-2.0 OR BSD-2-Clause
3 
4 /// @file
5 /// Geometric factors (3D) for Navier-Stokes example using PETSc
6 #pragma once
7 
8 #include <ceed/types.h>
9 #include "utils.h"
10 
11 /**
12  * @brief Calculate dXdx from dxdX for 3D elements
13  *
14  * Reference (parent) coordinates: X
15  * Physical (current) coordinates: x
16  * Change of coordinate matrix: dxdX_{i,j} = x_{i,j} (indicial notation)
17  * Inverse of change of coordinate matrix: dXdx_{i,j} = (detJ^-1) * X_{i,j}
18  *
19  * Determinant of Jacobian:
20  *   detJ = J11*A11 + J21*A12 + J31*A13
21  *     Jij = Jacobian entry ij
22  *     Aij = Adjugate ij
23  *
24  * Inverse of Jacobian:
25  *   dXdx_i,j = Aij / detJ
26  *
27  * @param[in]  Q        Number of quadrature points
28  * @param[in]  i        Current quadrature point
29  * @param[in]  dxdX_q   Mapping Jacobian (gradient of the coordinate space)
30  * @param[out] dXdx     Inverse of mapping Jacobian at quadrature point i
31  * @param[out] detJ_ptr Determinate of the Jacobian, may be NULL is not desired
32  */
33 CEED_QFUNCTION_HELPER void InvertMappingJacobian_3D(CeedInt Q, CeedInt i, const CeedScalar (*dxdX_q)[3][CEED_Q_VLA], CeedScalar dXdx[3][3],
34                                                     CeedScalar *detJ_ptr) {
35   CeedScalar dxdX[3][3];
36 
37   GradUnpack3(Q, i, 3, (CeedScalar *)dxdX_q, dxdX);
38   // Compute Adjugate of dxdX
39   dXdx[0][0] = dxdX[1][1] * dxdX[2][2] - dxdX[1][2] * dxdX[2][1];
40   dXdx[0][1] = dxdX[0][2] * dxdX[2][1] - dxdX[0][1] * dxdX[2][2];
41   dXdx[0][2] = dxdX[0][1] * dxdX[1][2] - dxdX[0][2] * dxdX[1][1];
42   dXdx[1][0] = dxdX[1][2] * dxdX[2][0] - dxdX[1][0] * dxdX[2][2];
43   dXdx[1][1] = dxdX[0][0] * dxdX[2][2] - dxdX[0][2] * dxdX[2][0];
44   dXdx[1][2] = dxdX[0][2] * dxdX[1][0] - dxdX[0][0] * dxdX[1][2];
45   dXdx[2][0] = dxdX[1][0] * dxdX[2][1] - dxdX[1][1] * dxdX[2][0];
46   dXdx[2][1] = dxdX[0][1] * dxdX[2][0] - dxdX[0][0] * dxdX[2][1];
47   dXdx[2][2] = dxdX[0][0] * dxdX[1][1] - dxdX[0][1] * dxdX[1][0];
48 
49   const CeedScalar detJ = dxdX[0][0] * dXdx[0][0] + dxdX[1][0] * dXdx[0][1] + dxdX[2][0] * dXdx[0][2];
50   ScaleN((CeedScalar *)dXdx, 1 / detJ, 9);
51   if (detJ_ptr) *detJ_ptr = detJ;
52 }
53 
54 /**
55  * @brief Calculate dXdx from dxdX for 2D elements
56  *
57  * Reference (parent) coordinates: X
58  * Physical (current) coordinates: x
59  * Change of coordinate matrix: dxdX_{i,j} = x_{i,j} (indicial notation)
60  * Inverse of change of coordinate matrix: dXdx_{i,j} = (detJ^-1) * X_{i,j}
61  *
62  * Determinant of Jacobian:
63  *   detJ = J11*J22 - J21*J12
64  *     Jij = Jacobian entry ij
65  *     Aij = Adjugate ij
66  *
67  * Inverse of Jacobian:
68  *   dXdx_i,j = Aij / detJ
69  *
70  * @param[in]  Q        Number of quadrature points
71  * @param[in]  i        Current quadrature point
72  * @param[in]  dxdX_q   Mapping Jacobian (gradient of the coordinate space)
73  * @param[out] dXdx     Inverse of mapping Jacobian at quadrature point i
74  * @param[out] detJ_ptr Determinate of the Jacobian, may be NULL is not desired
75  */
76 CEED_QFUNCTION_HELPER void InvertMappingJacobian_2D(CeedInt Q, CeedInt i, const CeedScalar (*dxdX_q)[2][CEED_Q_VLA], CeedScalar dXdx[2][2],
77                                                     CeedScalar *detJ_ptr) {
78   CeedScalar dxdX[2][2];
79 
80   GradUnpack2(Q, i, 2, (CeedScalar *)dxdX_q, dxdX);
81   const CeedScalar detJ = dxdX[0][0] * dxdX[1][1] - dxdX[1][0] * dxdX[0][1];
82 
83   dXdx[0][0] = dxdX[1][1] / detJ;
84   dXdx[0][1] = -dxdX[0][1] / detJ;
85   dXdx[1][0] = -dxdX[1][0] / detJ;
86   dXdx[1][1] = dxdX[0][0] / detJ;
87   if (detJ_ptr) *detJ_ptr = detJ;
88 }
89 
90 /**
91  * @brief Calculate face element's normal vector from dxdX
92  *
93  * Reference (parent) 2D coordinates: X
94  * Physical (current) 3D coordinates: x
95  * Change of coordinate matrix:
96  *   dxdX_{i,j} = dx_i/dX_j (indicial notation) [3 * 2]
97  * Inverse change of coordinate matrix:
98  *   dXdx_{i,j} = dX_i/dx_j (indicial notation) [2 * 3]
99  *
100  * (N1,N2,N3) is given by the cross product of the columns of dxdX_{i,j}
101  *
102  * detJb is the magnitude of (N1,N2,N3)
103  *
104  * Normal vector = (N1,N2,N3) / detJb
105  *
106  * @param[in]  Q        Number of quadrature points
107  * @param[in]  i        Current quadrature point
108  * @param[in]  dxdX_q   Mapping Jacobian (gradient of the coordinate space)
109  * @param[out] normal   Inverse of mapping Jacobian at quadrature point i
110  * @param[out] detJ_ptr Determinate of the Jacobian, may be NULL is not desired
111  */
112 CEED_QFUNCTION_HELPER void NormalVectorFromdxdX_3D(CeedInt Q, CeedInt i, const CeedScalar (*dxdX_q)[3][CEED_Q_VLA], CeedScalar normal[3],
113                                                    CeedScalar *detJ_ptr) {
114   CeedScalar dxdX[3][2];
115 
116   GradUnpack2(Q, i, 3, (CeedScalar *)dxdX_q, dxdX);
117   // N1, N2, and N3 are given by the cross product of the columns of dxdX
118   normal[0] = dxdX[1][0] * dxdX[2][1] - dxdX[2][0] * dxdX[1][1];
119   normal[1] = dxdX[2][0] * dxdX[0][1] - dxdX[0][0] * dxdX[2][1];
120   normal[2] = dxdX[0][0] * dxdX[1][1] - dxdX[1][0] * dxdX[0][1];
121 
122   const CeedScalar detJ = Norm3(normal);
123   ScaleN(normal, 1 / detJ, 3);
124   if (detJ_ptr) *detJ_ptr = detJ;
125 }
126 
127 /**
128  * This QFunction sets up the geometric factor required for integration when reference coordinates are in 1D and the physical coordinates are in 2D
129  *
130  * Reference (parent) 1D coordinates: X
131  * Physical (current) 2D coordinates: x
132  * Change of coordinate vector:
133  *           N1 = dx_1/dX
134  *           N2 = dx_2/dX
135  *
136  * detJb is the magnitude of (N1,N2)
137  *
138  * We require the determinant of the Jacobian to properly compute integrals of the form: int( u v )
139  *
140  * Normal vector is given by the cross product of (N1,N2)/detJ and ẑ
141  *
142  * @param[in]  Q        Number of quadrature points
143  * @param[in]  i        Current quadrature point
144  * @param[in]  dxdX_q   Mapping Jacobian (gradient of the coordinate space)
145  * @param[out] normal   Inverse of mapping Jacobian at quadrature point i
146  * @param[out] detJ_ptr Determinate of the Jacobian, may be NULL is not desired
147  */
148 CEED_QFUNCTION_HELPER void NormalVectorFromdxdX_2D(CeedInt Q, CeedInt i, const CeedScalar (*dxdX_q)[CEED_Q_VLA], CeedScalar normal[2],
149                                                    CeedScalar *detJ_ptr) {
150   normal[0]              = dxdX_q[1][i];
151   normal[1]              = -dxdX_q[0][i];
152   const CeedScalar detJb = Norm2(normal);
153   ScaleN(normal, 1 / detJb, 2);
154   if (detJ_ptr) *detJ_ptr = detJb;
155 }
156 
157 /**
158  * @brief Calculate inverse of mapping Jacobian, (dxdX)^-1
159  *
160  * Reference (parent) 2D coordinates: X
161  * Physical (current) 3D coordinates: x
162  * Change of coordinate matrix:
163  *   dxdX_{i,j} = dx_i/dX_j (indicial notation) [3 * 2]
164  * Inverse change of coordinate matrix:
165  *   dXdx_{i,j} = dX_i/dx_j (indicial notation) [2 * 3]
166  *
167  * dXdx is calculated via Moore–Penrose inverse:
168  *
169  *   dX_i/dx_j = (dxdX^T dxdX)^(-1) dxdX
170  *             = (dx_l/dX_i * dx_l/dX_k)^(-1) dx_j/dX_k
171  *
172  * @param[in]  Q      Number of quadrature points
173  * @param[in]  i      Current quadrature point
174  * @param[in]  dxdX_q Mapping Jacobian (gradient of the coordinate space)
175  * @param[out] dXdx   Inverse of mapping Jacobian at quadrature point i
176  */
177 CEED_QFUNCTION_HELPER void InvertBoundaryMappingJacobian_3D(CeedInt Q, CeedInt i, const CeedScalar (*dxdX_q)[3][CEED_Q_VLA], CeedScalar dXdx[2][3]) {
178   CeedScalar dxdX[3][2];
179   GradUnpack2(Q, i, 3, (CeedScalar *)dxdX_q, dxdX);
180 
181   // dxdX_k,j * dxdX_j,k
182   CeedScalar dxdXTdxdX[2][2] = {{0.}};
183   for (CeedInt j = 0; j < 2; j++) {
184     for (CeedInt k = 0; k < 2; k++) {
185       for (CeedInt l = 0; l < 3; l++) dxdXTdxdX[j][k] += dxdX[l][j] * dxdX[l][k];
186     }
187   }
188 
189   const CeedScalar detdxdXTdxdX = dxdXTdxdX[0][0] * dxdXTdxdX[1][1] - dxdXTdxdX[1][0] * dxdXTdxdX[0][1];
190 
191   // Compute inverse of dxdXTdxdX
192   CeedScalar dxdXTdxdX_inv[2][2];
193   dxdXTdxdX_inv[0][0] = dxdXTdxdX[1][1] / detdxdXTdxdX;
194   dxdXTdxdX_inv[0][1] = -dxdXTdxdX[0][1] / detdxdXTdxdX;
195   dxdXTdxdX_inv[1][0] = -dxdXTdxdX[1][0] / detdxdXTdxdX;
196   dxdXTdxdX_inv[1][1] = dxdXTdxdX[0][0] / detdxdXTdxdX;
197 
198   // Compute dXdx from dxdXTdxdX^-1 and dxdX
199   for (CeedInt j = 0; j < 2; j++) {
200     for (CeedInt k = 0; k < 3; k++) {
201       dXdx[j][k] = 0;
202       for (CeedInt l = 0; l < 2; l++) dXdx[j][k] += dxdXTdxdX_inv[l][j] * dxdX[k][l];
203     }
204   }
205 }
206