xref: /honee/qfunctions/setupgeo_helpers.h (revision efe705f2ed681857c82869855c5fbb66074f73c7)
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.h>
9 #include <math.h>
10 
11 #include "utils.h"
12 
13 /**
14  * @brief Calculate dXdx from dxdX for 3D elements
15  *
16  * Reference (parent) coordinates: X
17  * Physical (current) coordinates: x
18  * Change of coordinate matrix: dxdX_{i,j} = x_{i,j} (indicial notation)
19  * Inverse of change of coordinate matrix: dXdx_{i,j} = (detJ^-1) * X_{i,j}
20  *
21  * Determinant of Jacobian:
22  *   detJ = J11*A11 + J21*A12 + J31*A13
23  *     Jij = Jacobian entry ij
24  *     Aij = Adjugate ij
25  *
26  * Inverse of Jacobian:
27  *   dXdx_i,j = Aij / detJ
28  *
29  * @param[in]  Q        Number of quadrature points
30  * @param[in]  i        Current quadrature point
31  * @param[in]  dxdX_q   Mapping Jacobian (gradient of the coordinate space)
32  * @param[out] dXdx     Inverse of mapping Jacobian at quadrature point i
33  * @param[out] detJ_ptr Determinate of the Jacobian, may be NULL is not desired
34  */
35 CEED_QFUNCTION_HELPER void InvertMappingJacobian_3D(CeedInt Q, CeedInt i, const CeedScalar (*dxdX_q)[3][CEED_Q_VLA], CeedScalar dXdx[3][3],
36                                                     CeedScalar *detJ_ptr) {
37   CeedScalar dxdX[3][3];
38 
39   GradUnpack3(Q, i, 3, (CeedScalar *)dxdX_q, dxdX);
40   // Compute Adjugate of dxdX
41   dXdx[0][0] = dxdX[1][1] * dxdX[2][2] - dxdX[1][2] * dxdX[2][1];
42   dXdx[0][1] = dxdX[0][2] * dxdX[2][1] - dxdX[0][1] * dxdX[2][2];
43   dXdx[0][2] = dxdX[0][1] * dxdX[1][2] - dxdX[0][2] * dxdX[1][1];
44   dXdx[1][0] = dxdX[1][2] * dxdX[2][0] - dxdX[1][0] * dxdX[2][2];
45   dXdx[1][1] = dxdX[0][0] * dxdX[2][2] - dxdX[0][2] * dxdX[2][0];
46   dXdx[1][2] = dxdX[0][2] * dxdX[1][0] - dxdX[0][0] * dxdX[1][2];
47   dXdx[2][0] = dxdX[1][0] * dxdX[2][1] - dxdX[1][1] * dxdX[2][0];
48   dXdx[2][1] = dxdX[0][1] * dxdX[2][0] - dxdX[0][0] * dxdX[2][1];
49   dXdx[2][2] = dxdX[0][0] * dxdX[1][1] - dxdX[0][1] * dxdX[1][0];
50 
51   const CeedScalar detJ = dxdX[0][0] * dXdx[0][0] + dxdX[1][0] * dXdx[0][1] + dxdX[2][0] * dXdx[0][2];
52   ScaleN((CeedScalar *)dXdx, 1 / detJ, 9);
53   if (detJ_ptr) *detJ_ptr = detJ;
54 }
55 
56 /**
57  * @brief Calculate dXdx from dxdX for 2D elements
58  *
59  * Reference (parent) coordinates: X
60  * Physical (current) coordinates: x
61  * Change of coordinate matrix: dxdX_{i,j} = x_{i,j} (indicial notation)
62  * Inverse of change of coordinate matrix: dXdx_{i,j} = (detJ^-1) * X_{i,j}
63  *
64  * Determinant of Jacobian:
65  *   detJ = J11*J22 - J21*J12
66  *     Jij = Jacobian entry ij
67  *     Aij = Adjugate ij
68  *
69  * Inverse of Jacobian:
70  *   dXdx_i,j = Aij / detJ
71  *
72  * @param[in]  Q        Number of quadrature points
73  * @param[in]  i        Current quadrature point
74  * @param[in]  dxdX_q   Mapping Jacobian (gradient of the coordinate space)
75  * @param[out] dXdx     Inverse of mapping Jacobian at quadrature point i
76  * @param[out] detJ_ptr Determinate of the Jacobian, may be NULL is not desired
77  */
78 CEED_QFUNCTION_HELPER void InvertMappingJacobian_2D(CeedInt Q, CeedInt i, const CeedScalar (*dxdX_q)[2][CEED_Q_VLA], CeedScalar dXdx[2][2],
79                                                     CeedScalar *detJ_ptr) {
80   CeedScalar dxdX[2][2];
81 
82   GradUnpack2(Q, i, 2, (CeedScalar *)dxdX_q, dxdX);
83   const CeedScalar detJ = dxdX[0][0] * dxdX[1][1] - dxdX[1][0] * dxdX[0][1];
84 
85   dXdx[0][0] = dxdX[1][1] / detJ;
86   dXdx[0][1] = -dxdX[0][1] / detJ;
87   dXdx[1][0] = -dxdX[1][0] / detJ;
88   dXdx[1][1] = dxdX[0][0] / detJ;
89   if (detJ_ptr) *detJ_ptr = detJ;
90 }
91 
92 /**
93  * @brief Calculate face element's normal vector from dxdX
94  *
95  * Reference (parent) 2D coordinates: X
96  * Physical (current) 3D coordinates: x
97  * Change of coordinate matrix:
98  *   dxdX_{i,j} = dx_i/dX_j (indicial notation) [3 * 2]
99  * Inverse change of coordinate matrix:
100  *   dXdx_{i,j} = dX_i/dx_j (indicial notation) [2 * 3]
101  *
102  * (N1,N2,N3) is given by the cross product of the columns of dxdX_{i,j}
103  *
104  * detJb is the magnitude of (N1,N2,N3)
105  *
106  * Normal vector = (N1,N2,N3) / detJb
107  *
108  * @param[in]  Q        Number of quadrature points
109  * @param[in]  i        Current quadrature point
110  * @param[in]  dxdX_q   Mapping Jacobian (gradient of the coordinate space)
111  * @param[out] normal   Inverse of mapping Jacobian at quadrature point i
112  * @param[out] detJ_ptr Determinate of the Jacobian, may be NULL is not desired
113  */
114 CEED_QFUNCTION_HELPER void NormalVectorFromdxdX_3D(CeedInt Q, CeedInt i, const CeedScalar (*dxdX_q)[3][CEED_Q_VLA], CeedScalar normal[3],
115                                                    CeedScalar *detJ_ptr) {
116   CeedScalar dxdX[3][2];
117 
118   GradUnpack2(Q, i, 3, (CeedScalar *)dxdX_q, dxdX);
119   // N1, N2, and N3 are given by the cross product of the columns of dxdX
120   normal[0] = dxdX[1][0] * dxdX[2][1] - dxdX[2][0] * dxdX[1][1];
121   normal[1] = dxdX[2][0] * dxdX[0][1] - dxdX[0][0] * dxdX[2][1];
122   normal[2] = dxdX[0][0] * dxdX[1][1] - dxdX[1][0] * dxdX[0][1];
123 
124   const CeedScalar detJ = Norm3(normal);
125   ScaleN(normal, 1 / detJ, 3);
126   if (detJ_ptr) *detJ_ptr = detJ;
127 }
128 
129 /**
130  * This QFunction sets up the geometric factor required for integration when reference coordinates are in 1D and the physical coordinates are in 2D
131  *
132  * Reference (parent) 1D coordinates: X
133  * Physical (current) 2D coordinates: x
134  * Change of coordinate vector:
135  *           N1 = dx_1/dX
136  *           N2 = dx_2/dX
137  *
138  * detJb is the magnitude of (N1,N2)
139  *
140  * We require the determinant of the Jacobian to properly compute integrals of the form: int( u v )
141  *
142  * Normal vector is given by the cross product of (N1,N2)/detJ and ẑ
143  *
144  * @param[in]  Q        Number of quadrature points
145  * @param[in]  i        Current quadrature point
146  * @param[in]  dxdX_q   Mapping Jacobian (gradient of the coordinate space)
147  * @param[out] normal   Inverse of mapping Jacobian at quadrature point i
148  * @param[out] detJ_ptr Determinate of the Jacobian, may be NULL is not desired
149  */
150 CEED_QFUNCTION_HELPER void NormalVectorFromdxdX_2D(CeedInt Q, CeedInt i, const CeedScalar (*dxdX_q)[CEED_Q_VLA], CeedScalar normal[2],
151                                                    CeedScalar *detJ_ptr) {
152   normal[0]              = dxdX_q[1][i];
153   normal[1]              = -dxdX_q[0][i];
154   const CeedScalar detJb = Norm2(normal);
155   ScaleN(normal, 1 / detJb, 2);
156   if (detJ_ptr) *detJ_ptr = detJb;
157 }
158 
159 /**
160  * @brief Calculate inverse of mapping Jacobian, (dxdX)^-1
161  *
162  * Reference (parent) 2D coordinates: X
163  * Physical (current) 3D coordinates: x
164  * Change of coordinate matrix:
165  *   dxdX_{i,j} = dx_i/dX_j (indicial notation) [3 * 2]
166  * Inverse change of coordinate matrix:
167  *   dXdx_{i,j} = dX_i/dx_j (indicial notation) [2 * 3]
168  *
169  * dXdx is calculated via Moore–Penrose inverse:
170  *
171  *   dX_i/dx_j = (dxdX^T dxdX)^(-1) dxdX
172  *             = (dx_l/dX_i * dx_l/dX_k)^(-1) dx_j/dX_k
173  *
174  * @param[in]  Q      Number of quadrature points
175  * @param[in]  i      Current quadrature point
176  * @param[in]  dxdX_q Mapping Jacobian (gradient of the coordinate space)
177  * @param[out] dXdx   Inverse of mapping Jacobian at quadrature point i
178  */
179 CEED_QFUNCTION_HELPER void InvertBoundaryMappingJacobian_3D(CeedInt Q, CeedInt i, const CeedScalar (*dxdX_q)[3][CEED_Q_VLA], CeedScalar dXdx[2][3]) {
180   CeedScalar dxdX[3][2];
181   GradUnpack2(Q, i, 3, (CeedScalar *)dxdX_q, dxdX);
182 
183   // dxdX_k,j * dxdX_j,k
184   CeedScalar dxdXTdxdX[2][2] = {{0.}};
185   for (CeedInt j = 0; j < 2; j++) {
186     for (CeedInt k = 0; k < 2; k++) {
187       for (CeedInt l = 0; l < 3; l++) dxdXTdxdX[j][k] += dxdX[l][j] * dxdX[l][k];
188     }
189   }
190 
191   const CeedScalar detdxdXTdxdX = dxdXTdxdX[0][0] * dxdXTdxdX[1][1] - dxdXTdxdX[1][0] * dxdXTdxdX[0][1];
192 
193   // Compute inverse of dxdXTdxdX
194   CeedScalar dxdXTdxdX_inv[2][2];
195   dxdXTdxdX_inv[0][0] = dxdXTdxdX[1][1] / detdxdXTdxdX;
196   dxdXTdxdX_inv[0][1] = -dxdXTdxdX[0][1] / detdxdXTdxdX;
197   dxdXTdxdX_inv[1][0] = -dxdXTdxdX[1][0] / detdxdXTdxdX;
198   dxdXTdxdX_inv[1][1] = dxdXTdxdX[0][0] / detdxdXTdxdX;
199 
200   // Compute dXdx from dxdXTdxdX^-1 and dxdX
201   for (CeedInt j = 0; j < 2; j++) {
202     for (CeedInt k = 0; k < 3; k++) {
203       dXdx[j][k] = 0;
204       for (CeedInt l = 0; l < 2; l++) dXdx[j][k] += dxdXTdxdX_inv[l][j] * dxdX[k][l];
205     }
206   }
207 }
208