xref: /petsc/src/ts/tutorials/ex76.c (revision d547623e237931bedb17b336da7d6656fbea55a4)
1 static char help[] = "Time-dependent Low Mach Flow in 2d and 3d channels with finite elements.\n\
2 We solve the Low Mach flow problem in a rectangular\n\
3 domain, using a parallel unstructured mesh (DMPLEX) to discretize it.\n\n\n";
4 
5 /*F
6 This Low Mach flow is time-dependent isoviscous Navier-Stokes flow. We discretize using the
7 finite element method on an unstructured mesh. The weak form equations are
8 
9 \begin{align*}
10     < q, \nabla\cdot u > = 0
11     <v, du/dt> + <v, u \cdot \nabla u> + < \nabla v, \nu (\nabla u + {\nabla u}^T) > - < \nabla\cdot v, p >  - < v, f  >  = 0
12     < w, u \cdot \nabla T > + < \nabla w, \alpha \nabla T > - < w, Q > = 0
13 \end{align*}
14 
15 where $\nu$ is the kinematic viscosity and $\alpha$ is thermal diffusivity.
16 
17 For visualization, use
18 
19   -dm_view hdf5:$PWD/sol.h5 -sol_vec_view hdf5:$PWD/sol.h5::append -exact_vec_view hdf5:$PWD/sol.h5::append
20 F*/
21 
22 #include <petscdmplex.h>
23 #include <petscsnes.h>
24 #include <petscts.h>
25 #include <petscds.h>
26 #include <petscbag.h>
27 
28 typedef enum {SOL_QUADRATIC, SOL_CUBIC, SOL_CUBIC_TRIG, SOL_TAYLOR_GREEN, NUM_SOL_TYPES} SolType;
29 const char *solTypes[NUM_SOL_TYPES+1] = {"quadratic", "cubic", "cubic_trig", "taylor_green", "unknown"};
30 
31 typedef struct {
32   PetscReal nu;    /* Kinematic viscosity */
33   PetscReal alpha; /* Thermal diffusivity */
34   PetscReal T_in;  /* Inlet temperature*/
35 } Parameter;
36 
37 typedef struct {
38   /* Problem definition */
39   PetscBag bag;     /* Holds problem parameters */
40   SolType  solType; /* MMS solution type */
41   /* Flow diagnostics */
42   DM       dmCell;  /* A DM with piecewise constant discretization */
43 } AppCtx;
44 
45 static PetscErrorCode zero(PetscInt dim, PetscReal time, const PetscReal x[], PetscInt Nc, PetscScalar *u, void *ctx)
46 {
47   PetscInt d;
48   for (d = 0; d < Nc; ++d) u[d] = 0.0;
49   return 0;
50 }
51 
52 static PetscErrorCode constant(PetscInt dim, PetscReal time, const PetscReal x[], PetscInt Nc, PetscScalar *u, void *ctx)
53 {
54   PetscInt d;
55   for (d = 0; d < Nc; ++d) u[d] = 1.0;
56   return 0;
57 }
58 
59 /*
60   CASE: quadratic
61   In 2D we use exact solution:
62 
63     u = t + x^2 + y^2
64     v = t + 2x^2 - 2xy
65     p = x + y - 1
66     T = t + x + y
67     f = <t (2x + 2y) + 2x^3 + 4x^2y - 2xy^2 -4\nu + 2, t (2x - 2y) + 4xy^2 + 2x^2y - 2y^3 -4\nu + 2>
68     Q = 1 + 2t + 3x^2 - 2xy + y^2
69 
70   so that
71 
72     \nabla \cdot u = 2x - 2x = 0
73 
74   f = du/dt + u \cdot \nabla u - \nu \Delta u + \nabla p
75     = <1, 1> + <t + x^2 + y^2, t + 2x^2 - 2xy> . <<2x, 4x - 2y>, <2y, -2x>> - \nu <4, 4> + <1, 1>
76     = <t (2x + 2y) + 2x^3 + 4x^2y - 2xy^2, t (2x - 2y) + 2x^2y + 4xy^2 - 2y^3> + <-4 \nu + 2, -4\nu + 2>
77     = <t (2x + 2y) + 2x^3 + 4x^2y - 2xy^2 - 4\nu + 2, t (2x - 2y) + 4xy^2 + 2x^2y - 2y^3 - 4\nu + 2>
78 
79   Q = dT/dt + u \cdot \nabla T - \alpha \Delta T
80     = 1 + <t + x^2 + y^2, t + 2x^2 - 2xy> . <1, 1> - \alpha 0
81     = 1 + 2t + 3x^2 - 2xy + y^2
82 */
83 
84 static PetscErrorCode quadratic_u(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *u, void *ctx)
85 {
86   u[0] = time + X[0]*X[0] + X[1]*X[1];
87   u[1] = time + 2.0*X[0]*X[0] - 2.0*X[0]*X[1];
88   return 0;
89 }
90 static PetscErrorCode quadratic_u_t(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *u, void *ctx)
91 {
92   u[0] = 1.0;
93   u[1] = 1.0;
94   return 0;
95 }
96 
97 static PetscErrorCode quadratic_p(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *p, void *ctx)
98 {
99   p[0] = X[0] + X[1] - 1.0;
100   return 0;
101 }
102 
103 static PetscErrorCode quadratic_T(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *T, void *ctx)
104 {
105   T[0] = time + X[0] + X[1];
106   return 0;
107 }
108 static PetscErrorCode quadratic_T_t(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *T, void *ctx)
109 {
110   T[0] = 1.0;
111   return 0;
112 }
113 
114 /* f0_v = du/dt - f */
115 static void f0_quadratic_v(PetscInt dim, PetscInt Nf, PetscInt NfAux,
116                            const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
117                            const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
118                            PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
119 {
120   const PetscReal nu = PetscRealPart(constants[0]);
121   PetscInt        Nc = dim;
122   PetscInt        c, d;
123 
124   for (d = 0; d<dim; ++d) f0[d] = u_t[uOff[0]+d];
125 
126   for (c = 0; c < Nc; ++c) {
127     for (d = 0; d < dim; ++d) f0[c] += u[d]*u_x[c*dim+d];
128   }
129   f0[0] -= (t*(2*X[0] + 2*X[1]) + 2*X[0]*X[0]*X[0] + 4*X[0]*X[0]*X[1] - 2*X[0]*X[1]*X[1] - 4.0*nu + 2);
130   f0[1] -= (t*(2*X[0] - 2*X[1]) + 4*X[0]*X[1]*X[1] + 2*X[0]*X[0]*X[1] - 2*X[1]*X[1]*X[1] - 4.0*nu + 2);
131 }
132 
133 /* f0_w = dT/dt + u.grad(T) - Q */
134 static void f0_quadratic_w(PetscInt dim, PetscInt Nf, PetscInt NfAux,
135                            const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
136                            const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
137                            PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
138 {
139   PetscInt d;
140   f0[0] = 0;
141   for (d = 0; d < dim; ++d) f0[0] += u[uOff[0]+d]*u_x[uOff_x[2]+d];
142   f0[0] += u_t[uOff[2]] - (2*t + 1 + 3*X[0]*X[0] - 2*X[0]*X[1] + X[1]*X[1]);
143 }
144 
145 /*
146   CASE: cubic
147   In 2D we use exact solution:
148 
149     u = t + x^3 + y^3
150     v = t + 2x^3 - 3x^2y
151     p = 3/2 x^2 + 3/2 y^2 - 1
152     T = t + 1/2 x^2 + 1/2 y^2
153     f = < t(3x^2 + 3y^2) + 3x^5 + 6x^3y^2 - 6x^2y^3 - \nu(6x + 6y) + 3x + 1,
154           t(3x^2 - 6xy) + 6x^2y^3 + 3x^4y - 6xy^4 - \nu(12x - 6y) + 3y + 1>
155     Q = x^4 + xy^3 + 2x^3y - 3x^2y^2 + xt + yt - 2\alpha + 1
156 
157   so that
158 
159     \nabla \cdot u = 3x^2 - 3x^2 = 0
160 
161   du/dt + u \cdot \nabla u - \nu \Delta u + \nabla p - f
162   = <1,1> + <t(3x^2 + 3y^2) + 3x^5 + 6x^3y^2 - 6x^2y^3, t(3x^2 - 6xy) + 6x^2y^3 + 3x^4y - 6xy^4> - \nu<6x + 6y, 12x - 6y> + <3x, 3y> - <t(3x^2 + 3y^2) + 3x^5 + 6x^3y^2 - 6x^2y^3 - \nu(6x + 6y) + 3x + 1, t(3x^2 - 6xy) + 6x^2y^3 + 3x^4y - 6xy^4 - \nu(12x - 6y) + 3y + 1>  = 0
163 
164   dT/dt + u \cdot \nabla T - \alpha \Delta T - Q = 1 + (x^3 + y^3) x + (2x^3 - 3x^2y) y - 2*\alpha - (x^4 + xy^3 + 2x^3y - 3x^2y^2 - 2*\alpha +1)   = 0
165 */
166 static PetscErrorCode cubic_u(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *u, void *ctx)
167 {
168   u[0] = time + X[0]*X[0]*X[0] + X[1]*X[1]*X[1];
169   u[1] = time + 2.0*X[0]*X[0]*X[0] - 3.0*X[0]*X[0]*X[1];
170   return 0;
171 }
172 static PetscErrorCode cubic_u_t(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *u, void *ctx)
173 {
174   u[0] = 1.0;
175   u[1] = 1.0;
176   return 0;
177 }
178 
179 static PetscErrorCode cubic_p(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *p, void *ctx)
180 {
181   p[0] = 3.0*X[0]*X[0]/2.0 + 3.0*X[1]*X[1]/2.0 - 1.0;
182   return 0;
183 }
184 
185 static PetscErrorCode cubic_T(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *T, void *ctx)
186 {
187   T[0] = time + X[0]*X[0]/2.0 + X[1]*X[1]/2.0;
188   return 0;
189 }
190 static PetscErrorCode cubic_T_t(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *T, void *ctx)
191 {
192   T[0] = 1.0;
193   return 0;
194 }
195 
196 
197 static void f0_cubic_v(PetscInt dim, PetscInt Nf, PetscInt NfAux,
198                        const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
199                        const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
200                        PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
201 {
202   PetscInt                   c, d;
203   PetscInt                   Nc = dim;
204   const PetscReal            nu = PetscRealPart(constants[0]);
205 
206   for (d=0; d<dim; ++d) f0[d] = u_t[uOff[0]+d];
207 
208   for (c=0; c<Nc; ++c) {
209     for (d=0; d<dim; ++d) f0[c] += u[d]*u_x[c*dim+d];
210   }
211   f0[0] -= (t*(3*X[0]*X[0] + 3*X[1]*X[1]) + 3*X[0]*X[0]*X[0]*X[0]*X[0] + 6*X[0]*X[0]*X[0]*X[1]*X[1] - 6*X[0]*X[0]*X[1]*X[1]*X[1] - ( 6*X[0] + 6*X[1])*nu + 3*X[0] + 1);
212   f0[1] -= (t*(3*X[0]*X[0] - 6*X[0]*X[1]) + 3*X[0]*X[0]*X[0]*X[0]*X[1] + 6*X[0]*X[0]*X[1]*X[1]*X[1] - 6*X[0]*X[1]*X[1]*X[1]*X[1] - (12*X[0] - 6*X[1])*nu + 3*X[1] + 1);
213 }
214 
215 static void f0_cubic_w(PetscInt dim, PetscInt Nf, PetscInt NfAux,
216                        const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
217                        const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
218                        PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
219 {
220   PetscInt              d;
221   const PetscReal alpha = PetscRealPart(constants[1]);
222 
223   for (d = 0, f0[0] = 0; d < dim; ++d) f0[0] += u[uOff[0]+d]*u_x[uOff_x[2]+d];
224   f0[0] += u_t[uOff[2]] - (X[0]*X[0]*X[0]*X[0] + 2.0*X[0]*X[0]*X[0]*X[1] - 3.0*X[0]*X[0]*X[1]*X[1] + X[0]*X[1]*X[1]*X[1] + X[0]*t + X[1]*t - 2.0*alpha + 1);
225 }
226 
227 /*
228   CASE: cubic-trigonometric
229   In 2D we use exact solution:
230 
231     u = beta cos t + x^3 + y^3
232     v = beta sin t + 2x^3 - 3x^2y
233     p = 3/2 x^2 + 3/2 y^2 - 1
234     T = 20 cos t + 1/2 x^2 + 1/2 y^2
235     f = < beta cos t 3x^2         + beta sin t (3y^2 - 1) + 3x^5 + 6x^3y^2 - 6x^2y^3 - \nu(6x + 6y)  + 3x,
236           beta cos t (6x^2 - 6xy) - beta sin t (3x^2)     + 3x^4y + 6x^2y^3 - 6xy^4  - \nu(12x - 6y) + 3y>
237     Q = beta cos t x + beta sin t (y - 1) + x^4 + 2x^3y - 3x^2y^2 + xy^3 - 2\alpha
238 
239   so that
240 
241     \nabla \cdot u = 3x^2 - 3x^2 = 0
242 
243   f = du/dt + u \cdot \nabla u - \nu \Delta u + \nabla p
244     = <-sin t, cos t> + <cos t + x^3 + y^3, sin t + 2x^3 - 3x^2y> <<3x^2, 6x^2 - 6xy>, <3y^2, -3x^2>> - \nu <6x + 6y, 12x - 6y> + <3x, 3y>
245     = <-sin t, cos t> + <cos t 3x^2 + 3x^5 + 3x^2y^3 + sin t 3y^2 + 6x^3y^2 - 9x^2y^3, cos t (6x^2 - 6xy) + 6x^5 - 6x^4y + 6x^2y^3 - 6xy^4 + sin t (-3x^2) - 6x^5 + 9x^4y> - \nu <6x + 6y, 12x - 6y> + <3x, 3y>
246     = <cos t (3x^2)       + sin t (3y^2 - 1) + 3x^5 + 6x^3y^2 - 6x^2y^3 - \nu (6x + 6y)  + 3x,
247        cos t (6x^2 - 6xy) - sin t (3x^2)     + 3x^4y + 6x^2y^3 - 6xy^4  - \nu (12x - 6y) + 3y>
248 
249   Q = dT/dt + u \cdot \nabla T - \alpha \Delta T
250     = -sin t + <cos t + x^3 + y^3, sin t + 2x^3 - 3x^2y> . <x, y> - 2 \alpha
251     = -sin t + cos t (x) + x^4 + xy^3 + sin t (y) + 2x^3y - 3x^2y^2 - 2 \alpha
252     = cos t x + sin t (y - 1) + (x^4 + 2x^3y - 3x^2y^2 + xy^3 - 2 \alpha)
253 */
254 static PetscErrorCode cubic_trig_u(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *u, void *ctx)
255 {
256   u[0] = 100.*PetscCosReal(time) + X[0]*X[0]*X[0] + X[1]*X[1]*X[1];
257   u[1] = 100.*PetscSinReal(time) + 2.0*X[0]*X[0]*X[0] - 3.0*X[0]*X[0]*X[1];
258   return 0;
259 }
260 static PetscErrorCode cubic_trig_u_t(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *u, void *ctx)
261 {
262   u[0] = -100.*PetscSinReal(time);
263   u[1] =  100.*PetscCosReal(time);
264   return 0;
265 }
266 
267 static PetscErrorCode cubic_trig_p(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *p, void *ctx)
268 {
269   p[0] = 3.0*X[0]*X[0]/2.0 + 3.0*X[1]*X[1]/2.0 - 1.0;
270   return 0;
271 }
272 
273 static PetscErrorCode cubic_trig_T(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *T, void *ctx)
274 {
275   T[0] = 100.*PetscCosReal(time) + X[0]*X[0]/2.0 + X[1]*X[1]/2.0;
276   return 0;
277 }
278 static PetscErrorCode cubic_trig_T_t(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *T, void *ctx)
279 {
280   T[0] = -100.*PetscSinReal(time);
281   return 0;
282 }
283 
284 static void f0_cubic_trig_v(PetscInt dim, PetscInt Nf, PetscInt NfAux,
285                             const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
286                             const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
287                             PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
288 {
289   const PetscReal nu = PetscRealPart(constants[0]);
290   PetscInt        Nc = dim;
291   PetscInt        c, d;
292 
293   for (d = 0; d < dim; ++d) f0[d] = u_t[uOff[0]+d];
294 
295   for (c = 0; c < Nc; ++c) {
296     for (d = 0; d < dim; ++d) f0[c] += u[d]*u_x[c*dim+d];
297   }
298   f0[0] -= 100.*PetscCosReal(t)*(3*X[0]*X[0])               + 100.*PetscSinReal(t)*(3*X[1]*X[1] - 1.) + 3*X[0]*X[0]*X[0]*X[0]*X[0] + 6*X[0]*X[0]*X[0]*X[1]*X[1] - 6*X[0]*X[0]*X[1]*X[1]*X[1] - ( 6*X[0] + 6*X[1])*nu + 3*X[0];
299   f0[1] -= 100.*PetscCosReal(t)*(6*X[0]*X[0] - 6*X[0]*X[1]) - 100.*PetscSinReal(t)*(3*X[0]*X[0])      + 3*X[0]*X[0]*X[0]*X[0]*X[1] + 6*X[0]*X[0]*X[1]*X[1]*X[1] - 6*X[0]*X[1]*X[1]*X[1]*X[1] - (12*X[0] - 6*X[1])*nu + 3*X[1];
300 }
301 
302 static void f0_cubic_trig_w(PetscInt dim, PetscInt Nf, PetscInt NfAux,
303                             const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
304                             const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
305                             PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
306 {
307   const PetscReal alpha = PetscRealPart(constants[1]);
308   PetscInt        d;
309 
310   for (d = 0, f0[0] = 0; d < dim; ++d) f0[0] += u[uOff[0]+d]*u_x[uOff_x[2]+d];
311   f0[0] += u_t[uOff[2]] - (100.*PetscCosReal(t)*X[0] + 100.*PetscSinReal(t)*(X[1] - 1.) + X[0]*X[0]*X[0]*X[0] + 2.0*X[0]*X[0]*X[0]*X[1] - 3.0*X[0]*X[0]*X[1]*X[1] + X[0]*X[1]*X[1]*X[1] - 2.0*alpha);
312 }
313 
314 /*
315   CASE: taylor-green vortex
316   In 2D we use exact solution:
317 
318     u = 1 - cos(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t)
319     v = 1 + sin(\pi(x - t)) cos(\pi(y - t)) exp(-2 \pi^2 \nu t)
320     p = -1/4 [cos(2 \pi(x - t)) + cos(2 \pi(y - t))] exp(-4 \pi^2 \nu t)
321     T = t + x + y
322     f = <\nu \pi^2 exp(-2\nu \pi^2 t) cos(\pi(x-t)) sin(\pi(y-t)), -\nu \pi^2 exp(-2\nu \pi^2 t) sin(\pi(x-t)) cos(\pi(y-t))  >
323     Q = 3 + sin(\pi(x-y)) exp(-2\nu \pi^2 t)
324 
325   so that
326 
327   \nabla \cdot u = \pi sin(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t) - \pi sin(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t) = 0
328 
329   f = du/dt + u \cdot \nabla u - \nu \Delta u + \nabla p
330     = <-\pi (sin(\pi(x - t)) sin(\pi(y - t)) - cos(\pi(x - t)) cos(\pi(y - t)) - 2\pi cos(\pi(x - t)) sin(\pi(y - t))) exp(-2 \pi^2 \nu t),
331         \pi (sin(\pi(x - t)) sin(\pi(y - t)) - cos(\pi(x - t)) cos(\pi(y - t)) - 2\pi sin(\pi(x - t)) cos(\pi(y - t))) exp(-2 \pi^2 \nu t)>
332     + < \pi (1 - cos(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t)) sin(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t),
333         \pi (1 - cos(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t)) cos(\pi(x - t)) cos(\pi(y - t)) exp(-2 \pi^2 \nu t)>
334     + <-\pi (1 + sin(\pi(x - t)) cos(\pi(y - t)) exp(-2 \pi^2 \nu t)) cos(\pi(x - t)) cos(\pi(y - t)) exp(-2 \pi^2 \nu t),
335        -\pi (1 + sin(\pi(x - t)) cos(\pi(y - t)) exp(-2 \pi^2 \nu t)) sin(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t)>
336     + <-2\pi^2 cos(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t),
337         2\pi^2 sin(\pi(x - t)) cos(\pi(y - t)) exp(-2 \pi^2 \nu t)>
338     + < \pi/2 sin(2\pi(x - t)) exp(-4 \pi^2 \nu t),
339         \pi/2 sin(2\pi(y - t)) exp(-4 \pi^2 \nu t)>
340     = <-\pi (sin(\pi(x - t)) sin(\pi(y - t)) - cos(\pi(x - t)) cos(\pi(y - t)) - 2\pi cos(\pi(x - t)) sin(\pi(y - t))) exp(-2 \pi^2 \nu t),
341         \pi (sin(\pi(x - t)) sin(\pi(y - t)) - cos(\pi(x - t)) cos(\pi(y - t)) - 2\pi sin(\pi(x - t)) cos(\pi(y - t))) exp(-2 \pi^2 \nu t)>
342     + < \pi sin(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t),
343         \pi cos(\pi(x - t)) cos(\pi(y - t)) exp(-2 \pi^2 \nu t)>
344     + <-\pi cos(\pi(x - t)) cos(\pi(y - t)) exp(-2 \pi^2 \nu t),
345        -\pi sin(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t)>
346     + <-\pi/2 sin(2\pi(x - t)) exp(-4 \pi^2 \nu t),
347        -\pi/2 sin(2\pi(y - t)) exp(-4 \pi^2 \nu t)>
348     + <-2\pi^2 cos(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t),
349         2\pi^2 sin(\pi(x - t)) cos(\pi(y - t)) exp(-2 \pi^2 \nu t)>
350     + < \pi/2 sin(2\pi(x - t)) exp(-4 \pi^2 \nu t),
351         \pi/2 sin(2\pi(y - t)) exp(-4 \pi^2 \nu t)>
352     = <-\pi (sin(\pi(x - t)) sin(\pi(y - t)) - cos(\pi(x - t)) cos(\pi(y - t))) exp(-2 \pi^2 \nu t),
353         \pi (sin(\pi(x - t)) sin(\pi(y - t)) - cos(\pi(x - t)) cos(\pi(y - t))) exp(-2 \pi^2 \nu t)>
354     + < \pi sin(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t),
355         \pi cos(\pi(x - t)) cos(\pi(y - t)) exp(-2 \pi^2 \nu t)>
356     + <-\pi cos(\pi(x - t)) cos(\pi(y - t)) exp(-2 \pi^2 \nu t),
357        -\pi sin(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t)>
358     = < \pi cos(\pi(x - t)) cos(\pi(y - t)),
359         \pi sin(\pi(x - t)) sin(\pi(y - t))>
360     + <-\pi cos(\pi(x - t)) cos(\pi(y - t)),
361        -\pi sin(\pi(x - t)) sin(\pi(y - t))> = 0
362   Q = dT/dt + u \cdot \nabla T - \alpha \Delta T
363     = 1 + u \cdot <1, 1> - 0
364     = 1 + u + v
365 */
366 
367 static PetscErrorCode taylor_green_u(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *u, void *ctx)
368 {
369   u[0] = 1 - PetscCosReal(PETSC_PI*(X[0]-time))*PetscSinReal(PETSC_PI*(X[1]-time))*PetscExpReal(-2*PETSC_PI*PETSC_PI*time);
370   u[1] = 1 + PetscSinReal(PETSC_PI*(X[0]-time))*PetscCosReal(PETSC_PI*(X[1]-time))*PetscExpReal(-2*PETSC_PI*PETSC_PI*time);
371   return 0;
372 }
373 static PetscErrorCode taylor_green_u_t(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *u, void *ctx)
374 {
375   u[0] = -PETSC_PI*(PetscSinReal(PETSC_PI*(X[0]-time))*PetscSinReal(PETSC_PI*(X[1]-time))
376                   - PetscCosReal(PETSC_PI*(X[0]-time))*PetscCosReal(PETSC_PI*(X[1]-time))
377                   - 2*PETSC_PI*PetscCosReal(PETSC_PI*(X[0]-time))*PetscSinReal(PETSC_PI*(X[1]-time)))*PetscExpReal(-2*PETSC_PI*PETSC_PI*time);
378   u[1] =  PETSC_PI*(PetscSinReal(PETSC_PI*(X[0]-time))*PetscSinReal(PETSC_PI*(X[1]-time))
379                   - PetscCosReal(PETSC_PI*(X[0]-time))*PetscCosReal(PETSC_PI*(X[1]-time))
380                   - 2*PETSC_PI*PetscSinReal(PETSC_PI*(X[0]-time))*PetscCosReal(PETSC_PI*(X[1]-time)))*PetscExpReal(-2*PETSC_PI*PETSC_PI*time);
381   return 0;
382 }
383 
384 static PetscErrorCode taylor_green_p(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *p, void *ctx)
385 {
386   p[0] = -0.25*(PetscCosReal(2*PETSC_PI*(X[0]-time)) + PetscCosReal(2*PETSC_PI*(X[1]-time)))*PetscExpReal(-4*PETSC_PI*PETSC_PI*time);
387   return 0;
388 }
389 
390 static PetscErrorCode taylor_green_p_t(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *p, void *ctx)
391 {
392   p[0] = PETSC_PI*(0.5*(PetscSinReal(2*PETSC_PI*(X[0]-time)) + PetscSinReal(2*PETSC_PI*(X[1]-time)))
393                  + PETSC_PI*(PetscCosReal(2*PETSC_PI*(X[0]-time)) + PetscCosReal(2*PETSC_PI*(X[1]-time))))*PetscExpReal(-4*PETSC_PI*PETSC_PI*time);
394   return 0;
395 }
396 
397 static PetscErrorCode taylor_green_T(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *T, void *ctx)
398 {
399   T[0] = time + X[0] + X[1];
400   return 0;
401 }
402 static PetscErrorCode taylor_green_T_t(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *T, void *ctx)
403 {
404   T[0] = 1.0;
405   return 0;
406 }
407 
408 static void f0_taylor_green_v(PetscInt dim, PetscInt Nf, PetscInt NfAux,
409                             const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
410                             const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
411                             PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
412 {
413   PetscInt        Nc = dim;
414   PetscInt        c, d;
415 
416   for (d = 0; d < dim; ++d) f0[d] = u_t[uOff[0]+d];
417 
418   for (c = 0; c < Nc; ++c) {
419     for (d = 0; d < dim; ++d) f0[c] += u[d]*u_x[c*dim+d];
420   }
421 }
422 
423 static void f0_taylor_green_w(PetscInt dim, PetscInt Nf, PetscInt NfAux,
424                             const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
425                             const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
426                             PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
427 {
428   PetscScalar vel[2];
429   PetscInt    d;
430 
431   taylor_green_u(dim, t, X, Nf, vel, NULL);
432   for (d = 0, f0[0] = 0; d < dim; ++d) f0[0] += u[uOff[0]+d]*u_x[uOff_x[2]+d];
433   f0[0] += u_t[uOff[2]] - (1.0 + vel[0] + vel[1]);
434 }
435 
436 static void f0_q(PetscInt dim, PetscInt Nf, PetscInt NfAux,
437                  const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
438                  const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
439                  PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
440 {
441   PetscInt d;
442   for (d = 0, f0[0] = 0.0; d < dim; ++d) f0[0] += u_x[d*dim+d];
443 }
444 
445 /*f1_v = \nu[grad(u) + grad(u)^T] - pI */
446 static void f1_v(PetscInt dim, PetscInt Nf, PetscInt NfAux,
447                  const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
448                  const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
449                  PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f1[])
450 {
451   const PetscReal nu = PetscRealPart(constants[0]);
452   const PetscInt    Nc = dim;
453   PetscInt        c, d;
454 
455   for (c = 0; c < Nc; ++c) {
456     for (d = 0; d < dim; ++d) {
457       f1[c*dim+d] = nu*(u_x[c*dim+d] + u_x[d*dim+c]);
458     }
459     f1[c*dim+c] -= u[uOff[1]];
460   }
461 }
462 
463 static void f1_w(PetscInt dim, PetscInt Nf, PetscInt NfAux,
464                  const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
465                  const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
466                  PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f1[])
467 {
468   const PetscReal alpha = PetscRealPart(constants[1]);
469   PetscInt d;
470   for (d = 0; d < dim; ++d) f1[d] = alpha*u_x[uOff_x[2]+d];
471 }
472 
473 /*Jacobians*/
474 static void g1_qu(PetscInt dim, PetscInt Nf, PetscInt NfAux,
475                  const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
476                  const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
477                  PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g1[])
478 {
479   PetscInt d;
480   for (d = 0; d < dim; ++d) g1[d*dim+d] = 1.0;
481 }
482 
483 static void g0_vu(PetscInt dim, PetscInt Nf, PetscInt NfAux,
484                   const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
485                   const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
486                   PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g0[])
487 {
488   PetscInt c, d;
489   const PetscInt  Nc = dim;
490 
491   for (d = 0; d < dim; ++d) g0[d*dim+d] = u_tShift;
492 
493   for (c = 0; c < Nc; ++c) {
494     for (d = 0; d < dim; ++d) {
495       g0[c*Nc+d] += u_x[ c*Nc+d];
496     }
497   }
498 }
499 
500 static void g1_vu(PetscInt dim, PetscInt Nf, PetscInt NfAux,
501                   const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
502                   const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
503                   PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g1[])
504 {
505   PetscInt NcI = dim;
506   PetscInt NcJ = dim;
507   PetscInt c, d, e;
508 
509   for (c = 0; c < NcI; ++c) {
510     for (d = 0; d < NcJ; ++d) {
511       for (e = 0; e < dim; ++e) {
512         if (c == d) {
513           g1[(c*NcJ+d)*dim+e] += u[e];
514         }
515       }
516     }
517   }
518 }
519 
520 
521 static void g2_vp(PetscInt dim, PetscInt Nf, PetscInt NfAux,
522                   const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
523                   const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
524                   PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g2[])
525 {
526   PetscInt d;
527   for (d = 0; d < dim; ++d) g2[d*dim+d] = -1.0;
528 }
529 
530 static void g3_vu(PetscInt dim, PetscInt Nf, PetscInt NfAux,
531                   const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
532                   const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
533                   PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g3[])
534 {
535    const PetscReal nu = PetscRealPart(constants[0]);
536    const PetscInt  Nc = dim;
537    PetscInt        c, d;
538 
539   for (c = 0; c < Nc; ++c) {
540     for (d = 0; d < dim; ++d) {
541       g3[((c*Nc+c)*dim+d)*dim+d] += nu;
542       g3[((c*Nc+d)*dim+d)*dim+c] += nu;
543     }
544   }
545 }
546 
547 static void g0_wT(PetscInt dim, PetscInt Nf, PetscInt NfAux,
548                   const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
549                   const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
550                   PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g0[])
551 {
552   g0[0] = u_tShift;
553 }
554 
555 static void g0_wu(PetscInt dim, PetscInt Nf, PetscInt NfAux,
556                   const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
557                   const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
558                   PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g0[])
559 {
560   PetscInt d;
561   for (d = 0; d < dim; ++d) g0[d] = u_x[uOff_x[2]+d];
562 }
563 
564 static void g1_wT(PetscInt dim, PetscInt Nf, PetscInt NfAux,
565                   const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
566                   const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
567                   PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g1[])
568 {
569   PetscInt d;
570   for (d = 0; d < dim; ++d) g1[d] = u[uOff[0]+d];
571 }
572 
573 static void g3_wT(PetscInt dim, PetscInt Nf, PetscInt NfAux,
574                   const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
575                   const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
576                   PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g3[])
577 {
578   const PetscReal alpha = PetscRealPart(constants[1]);
579   PetscInt               d;
580 
581   for (d = 0; d < dim; ++d) g3[d*dim+d] = alpha;
582 }
583 
584 static PetscErrorCode ProcessOptions(MPI_Comm comm, AppCtx *options)
585 {
586   PetscInt       sol;
587   PetscErrorCode ierr;
588 
589 
590   PetscFunctionBeginUser;
591   options->solType = SOL_QUADRATIC;
592 
593   ierr = PetscOptionsBegin(comm, "", "Low Mach flow Problem Options", "DMPLEX");CHKERRQ(ierr);
594   sol = options->solType;
595   ierr = PetscOptionsEList("-sol_type", "The solution type", "ex62.c", solTypes, NUM_SOL_TYPES, solTypes[options->solType], &sol, NULL);CHKERRQ(ierr);
596   options->solType = (SolType) sol;
597   ierr = PetscOptionsEnd();
598   PetscFunctionReturn(0);
599 }
600 
601 static PetscErrorCode SetupParameters(AppCtx *user)
602 {
603   PetscBag       bag;
604   Parameter     *p;
605   PetscErrorCode ierr;
606 
607   PetscFunctionBeginUser;
608   /* setup PETSc parameter bag */
609   ierr = PetscBagGetData(user->bag, (void **) &p);CHKERRQ(ierr);
610   ierr = PetscBagSetName(user->bag, "par", "Low Mach flow parameters");CHKERRQ(ierr);
611   bag  = user->bag;
612   ierr = PetscBagRegisterReal(bag, &p->nu,    1.0, "nu",    "Kinematic viscosity");CHKERRQ(ierr);
613   ierr = PetscBagRegisterReal(bag, &p->alpha, 1.0, "alpha", "Thermal diffusivity");CHKERRQ(ierr);
614   ierr = PetscBagRegisterReal(bag, &p->T_in,  1.0, "T_in",  "Inlet temperature");CHKERRQ(ierr);
615   PetscFunctionReturn(0);
616 }
617 
618 static PetscErrorCode CreateMesh(MPI_Comm comm, AppCtx *user, DM *dm)
619 {
620   PetscErrorCode ierr;
621 
622   PetscFunctionBeginUser;
623   ierr = DMPlexCreateBoxMesh(comm, 2, PETSC_TRUE, NULL, NULL, NULL, NULL, PETSC_TRUE, dm);CHKERRQ(ierr);
624   ierr = DMSetFromOptions(*dm);CHKERRQ(ierr);
625   ierr = DMViewFromOptions(*dm, NULL, "-dm_view");CHKERRQ(ierr);
626   PetscFunctionReturn(0);
627 }
628 
629 static PetscErrorCode SetupProblem(DM dm, AppCtx *user)
630 {
631   PetscSimplePointFunc exactFuncs[3];
632   PetscSimplePointFunc exactFuncs_t[3];
633   PetscDS              prob;
634   DMLabel              label;
635   Parameter           *ctx;
636   PetscInt             id;
637   PetscErrorCode       ierr;
638 
639   PetscFunctionBeginUser;
640   ierr = DMGetLabel(dm, "marker", &label);CHKERRQ(ierr);
641   ierr = DMGetDS(dm, &prob);CHKERRQ(ierr);
642   switch(user->solType){
643   case SOL_QUADRATIC:
644     ierr = PetscDSSetResidual(prob, 0, f0_quadratic_v, f1_v);CHKERRQ(ierr);
645     ierr = PetscDSSetResidual(prob, 2, f0_quadratic_w, f1_w);CHKERRQ(ierr);
646 
647     exactFuncs[0]   = quadratic_u;
648     exactFuncs[1]   = quadratic_p;
649     exactFuncs[2]   = quadratic_T;
650     exactFuncs_t[0] = quadratic_u_t;
651     exactFuncs_t[1] = NULL;
652     exactFuncs_t[2] = quadratic_T_t;
653     break;
654   case SOL_CUBIC:
655     ierr = PetscDSSetResidual(prob, 0, f0_cubic_v, f1_v);CHKERRQ(ierr);
656     ierr = PetscDSSetResidual(prob, 2, f0_cubic_w, f1_w);CHKERRQ(ierr);
657 
658     exactFuncs[0]   = cubic_u;
659     exactFuncs[1]   = cubic_p;
660     exactFuncs[2]   = cubic_T;
661     exactFuncs_t[0] = cubic_u_t;
662     exactFuncs_t[1] = NULL;
663     exactFuncs_t[2] = cubic_T_t;
664     break;
665   case SOL_CUBIC_TRIG:
666     ierr = PetscDSSetResidual(prob, 0, f0_cubic_trig_v, f1_v);CHKERRQ(ierr);
667     ierr = PetscDSSetResidual(prob, 2, f0_cubic_trig_w, f1_w);CHKERRQ(ierr);
668 
669     exactFuncs[0]   = cubic_trig_u;
670     exactFuncs[1]   = cubic_trig_p;
671     exactFuncs[2]   = cubic_trig_T;
672     exactFuncs_t[0] = cubic_trig_u_t;
673     exactFuncs_t[1] = NULL;
674     exactFuncs_t[2] = cubic_trig_T_t;
675     break;
676   case SOL_TAYLOR_GREEN:
677     ierr = PetscDSSetResidual(prob, 0, f0_taylor_green_v, f1_v);CHKERRQ(ierr);
678     ierr = PetscDSSetResidual(prob, 2, f0_taylor_green_w, f1_w);CHKERRQ(ierr);
679 
680     exactFuncs[0]   = taylor_green_u;
681     exactFuncs[1]   = taylor_green_p;
682     exactFuncs[2]   = taylor_green_T;
683     exactFuncs_t[0] = taylor_green_u_t;
684     exactFuncs_t[1] = taylor_green_p_t;
685     exactFuncs_t[2] = taylor_green_T_t;
686     break;
687    default: SETERRQ2(PetscObjectComm((PetscObject) prob), PETSC_ERR_ARG_WRONG, "Unsupported solution type: %s (%D)", solTypes[PetscMin(user->solType, NUM_SOL_TYPES)], user->solType);
688   }
689 
690   ierr = PetscDSSetResidual(prob, 1, f0_q, NULL);CHKERRQ(ierr);
691 
692   ierr = PetscDSSetJacobian(prob, 0, 0, g0_vu, g1_vu,  NULL,  g3_vu);CHKERRQ(ierr);
693   ierr = PetscDSSetJacobian(prob, 0, 1, NULL, NULL,  g2_vp, NULL);CHKERRQ(ierr);
694   ierr = PetscDSSetJacobian(prob, 1, 0, NULL, g1_qu, NULL,  NULL);CHKERRQ(ierr);
695   ierr = PetscDSSetJacobian(prob, 2, 0, g0_wu, NULL, NULL,  NULL);CHKERRQ(ierr);
696   ierr = PetscDSSetJacobian(prob, 2, 2, g0_wT, g1_wT, NULL,  g3_wT);CHKERRQ(ierr);
697   /* Setup constants */
698   {
699     Parameter  *param;
700     PetscScalar constants[3];
701 
702     ierr = PetscBagGetData(user->bag, (void **) &param);CHKERRQ(ierr);
703 
704     constants[0] = param->nu;
705     constants[1] = param->alpha;
706     constants[2] = param->T_in;
707     ierr = PetscDSSetConstants(prob, 3, constants);CHKERRQ(ierr);
708   }
709   /* Setup Boundary Conditions */
710   ierr = PetscBagGetData(user->bag, (void **) &ctx);CHKERRQ(ierr);
711   id   = 3;
712   ierr = PetscDSAddBoundary(prob, DM_BC_ESSENTIAL, "top wall velocity",    label, 1, &id, 0, 0, NULL, (void (*)(void)) exactFuncs[0], (void (*)(void)) exactFuncs_t[0], ctx, NULL);CHKERRQ(ierr);
713   id   = 1;
714   ierr = PetscDSAddBoundary(prob, DM_BC_ESSENTIAL, "bottom wall velocity", label, 1, &id, 0, 0, NULL, (void (*)(void)) exactFuncs[0], (void (*)(void)) exactFuncs_t[0], ctx, NULL);CHKERRQ(ierr);
715   id   = 2;
716   ierr = PetscDSAddBoundary(prob, DM_BC_ESSENTIAL, "right wall velocity",  label, 1, &id, 0, 0, NULL, (void (*)(void)) exactFuncs[0], (void (*)(void)) exactFuncs_t[0], ctx, NULL);CHKERRQ(ierr);
717   id   = 4;
718   ierr = PetscDSAddBoundary(prob, DM_BC_ESSENTIAL, "left wall velocity",   label, 1, &id, 0, 0, NULL, (void (*)(void)) exactFuncs[0], (void (*)(void)) exactFuncs_t[0], ctx, NULL);CHKERRQ(ierr);
719   id   = 3;
720   ierr = PetscDSAddBoundary(prob, DM_BC_ESSENTIAL, "top wall temp",    label, 1, &id, 2, 0, NULL, (void (*)(void)) exactFuncs[2], (void (*)(void)) exactFuncs_t[2], ctx, NULL);CHKERRQ(ierr);
721   id   = 1;
722   ierr = PetscDSAddBoundary(prob, DM_BC_ESSENTIAL, "bottom wall temp", label, 1, &id, 2, 0, NULL, (void (*)(void)) exactFuncs[2], (void (*)(void)) exactFuncs_t[2], ctx, NULL);CHKERRQ(ierr);
723   id   = 2;
724   ierr = PetscDSAddBoundary(prob, DM_BC_ESSENTIAL, "right wall temp",  label, 1, &id, 2, 0, NULL, (void (*)(void)) exactFuncs[2], (void (*)(void)) exactFuncs_t[2], ctx, NULL);CHKERRQ(ierr);
725   id   = 4;
726   ierr = PetscDSAddBoundary(prob, DM_BC_ESSENTIAL, "left wall temp",   label, 1, &id, 2, 0, NULL, (void (*)(void)) exactFuncs[2], (void (*)(void)) exactFuncs_t[2], ctx, NULL);CHKERRQ(ierr);
727 
728   /*setup exact solution.*/
729   ierr = PetscDSSetExactSolution(prob, 0, exactFuncs[0], ctx);CHKERRQ(ierr);
730   ierr = PetscDSSetExactSolution(prob, 1, exactFuncs[1], ctx);CHKERRQ(ierr);
731   ierr = PetscDSSetExactSolution(prob, 2, exactFuncs[2], ctx);CHKERRQ(ierr);
732   ierr = PetscDSSetExactSolutionTimeDerivative(prob, 0, exactFuncs_t[0], ctx);CHKERRQ(ierr);
733   ierr = PetscDSSetExactSolutionTimeDerivative(prob, 1, exactFuncs_t[1], ctx);CHKERRQ(ierr);
734   ierr = PetscDSSetExactSolutionTimeDerivative(prob, 2, exactFuncs_t[2], ctx);CHKERRQ(ierr);
735   PetscFunctionReturn(0);
736 }
737 
738 static PetscErrorCode SetupDiscretization(DM dm, AppCtx *user)
739 {
740   DM              cdm   = dm;
741   PetscFE         fe[3], fediv;
742   Parameter      *param;
743   DMPolytopeType  ct;
744   PetscInt        dim, cStart;
745   PetscBool       simplex;
746   PetscErrorCode  ierr;
747 
748   PetscFunctionBeginUser;
749   ierr = DMGetDimension(dm, &dim);CHKERRQ(ierr);
750   ierr = DMPlexGetHeightStratum(dm, 0, &cStart, NULL);CHKERRQ(ierr);
751   ierr = DMPlexGetCellType(dm, cStart, &ct);CHKERRQ(ierr);
752   simplex = DMPolytopeTypeGetNumVertices(ct) == DMPolytopeTypeGetDim(ct)+1 ? PETSC_TRUE : PETSC_FALSE;
753   /* Create finite element */
754   ierr = PetscFECreateDefault(PETSC_COMM_SELF, dim, dim, simplex, "vel_", PETSC_DEFAULT, &fe[0]);CHKERRQ(ierr);
755   ierr = PetscObjectSetName((PetscObject) fe[0], "velocity");CHKERRQ(ierr);
756 
757   ierr = PetscFECreateDefault(PETSC_COMM_SELF, dim, 1, simplex, "pres_", PETSC_DEFAULT, &fe[1]);CHKERRQ(ierr);
758   ierr = PetscFECopyQuadrature(fe[0], fe[1]);CHKERRQ(ierr);
759   ierr = PetscObjectSetName((PetscObject) fe[1], "pressure");CHKERRQ(ierr);
760 
761   ierr = PetscFECreateDefault(PETSC_COMM_SELF, dim, 1, simplex, "temp_", PETSC_DEFAULT, &fe[2]);CHKERRQ(ierr);
762   ierr = PetscFECopyQuadrature(fe[0], fe[2]);CHKERRQ(ierr);
763   ierr = PetscObjectSetName((PetscObject) fe[2], "temperature");CHKERRQ(ierr);
764 
765   ierr = PetscFECreateDefault(PETSC_COMM_SELF, dim, 1, simplex, "div_", PETSC_DEFAULT, &fediv);CHKERRQ(ierr);
766   ierr = PetscFECopyQuadrature(fe[0], fediv);CHKERRQ(ierr);
767   ierr = PetscObjectSetName((PetscObject) fediv, "divergence");CHKERRQ(ierr);
768 
769   /* Set discretization and boundary conditions for each mesh */
770   ierr = DMSetField(dm, 0, NULL, (PetscObject) fe[0]);CHKERRQ(ierr);
771   ierr = DMSetField(dm, 1, NULL, (PetscObject) fe[1]);CHKERRQ(ierr);
772   ierr = DMSetField(dm, 2, NULL, (PetscObject) fe[2]);CHKERRQ(ierr);
773   ierr = DMCreateDS(dm);CHKERRQ(ierr);
774   ierr = SetupProblem(dm, user);CHKERRQ(ierr);
775   ierr = PetscBagGetData(user->bag, (void **) &param);CHKERRQ(ierr);
776   while (cdm) {
777     ierr = DMCopyDisc(dm, cdm);CHKERRQ(ierr);
778     ierr = DMGetCoarseDM(cdm, &cdm);CHKERRQ(ierr);
779   }
780   ierr = PetscFEDestroy(&fe[0]);CHKERRQ(ierr);
781   ierr = PetscFEDestroy(&fe[1]);CHKERRQ(ierr);
782   ierr = PetscFEDestroy(&fe[2]);CHKERRQ(ierr);
783 
784   ierr = DMClone(dm, &user->dmCell);CHKERRQ(ierr);
785   ierr = DMSetField(user->dmCell, 0, NULL, (PetscObject) fediv);CHKERRQ(ierr);
786   ierr = DMCreateDS(user->dmCell);CHKERRQ(ierr);
787   ierr = PetscFEDestroy(&fediv);CHKERRQ(ierr);
788 
789   {
790     PetscObject  pressure;
791     MatNullSpace nullspacePres;
792 
793     ierr = DMGetField(dm, 1, NULL, &pressure);CHKERRQ(ierr);
794     ierr = MatNullSpaceCreate(PetscObjectComm(pressure), PETSC_TRUE, 0, NULL, &nullspacePres);CHKERRQ(ierr);
795     ierr = PetscObjectCompose(pressure, "nullspace", (PetscObject) nullspacePres);CHKERRQ(ierr);
796     ierr = MatNullSpaceDestroy(&nullspacePres);CHKERRQ(ierr);
797   }
798 
799   PetscFunctionReturn(0);
800 }
801 
802 static PetscErrorCode CreatePressureNullSpace(DM dm, PetscInt ofield, PetscInt nfield, MatNullSpace *nullSpace)
803 {
804   Vec              vec;
805   PetscErrorCode (*funcs[3])(PetscInt, PetscReal, const PetscReal[], PetscInt, PetscScalar *, void *) = {zero, zero, zero};
806   PetscErrorCode   ierr;
807 
808   PetscFunctionBeginUser;
809   if (ofield != 1) SETERRQ1(PetscObjectComm((PetscObject) dm), PETSC_ERR_ARG_WRONG, "Nullspace must be for pressure field at index 1, not %D", ofield);
810   funcs[nfield] = constant;
811   ierr = DMCreateGlobalVector(dm, &vec);CHKERRQ(ierr);
812   ierr = DMProjectFunction(dm, 0.0, funcs, NULL, INSERT_ALL_VALUES, vec);CHKERRQ(ierr);
813   ierr = VecNormalize(vec, NULL);CHKERRQ(ierr);
814   ierr = PetscObjectSetName((PetscObject) vec, "Pressure Null Space");CHKERRQ(ierr);
815   ierr = VecViewFromOptions(vec, NULL, "-pressure_nullspace_view");CHKERRQ(ierr);
816   ierr = MatNullSpaceCreate(PetscObjectComm((PetscObject) dm), PETSC_FALSE, 1, &vec, nullSpace);CHKERRQ(ierr);
817   ierr = VecDestroy(&vec);CHKERRQ(ierr);
818   PetscFunctionReturn(0);
819 }
820 
821 static PetscErrorCode RemoveDiscretePressureNullspace_Private(TS ts, Vec u)
822 {
823   DM             dm;
824   MatNullSpace   nullsp;
825   PetscErrorCode ierr;
826 
827   PetscFunctionBegin;
828   ierr = TSGetDM(ts, &dm);CHKERRQ(ierr);
829   ierr = CreatePressureNullSpace(dm, 1, 1, &nullsp);CHKERRQ(ierr);
830   ierr = MatNullSpaceRemove(nullsp, u);CHKERRQ(ierr);
831   ierr = MatNullSpaceDestroy(&nullsp);CHKERRQ(ierr);
832   PetscFunctionReturn(0);
833 }
834 
835 /* Make the discrete pressure discretely divergence free */
836 static PetscErrorCode RemoveDiscretePressureNullspace(TS ts)
837 {
838   Vec            u;
839   PetscErrorCode ierr;
840 
841   PetscFunctionBegin;
842   ierr = TSGetSolution(ts, &u);CHKERRQ(ierr);
843   ierr = RemoveDiscretePressureNullspace_Private(ts, u);CHKERRQ(ierr);
844   PetscFunctionReturn(0);
845 }
846 
847 static PetscErrorCode SetInitialConditions(TS ts, Vec u)
848 {
849   DM             dm;
850   PetscReal      t;
851   PetscErrorCode ierr;
852 
853   PetscFunctionBegin;
854   ierr = TSGetDM(ts, &dm);CHKERRQ(ierr);
855   ierr = TSGetTime(ts, &t);CHKERRQ(ierr);
856   ierr = DMComputeExactSolution(dm, t, u, NULL);CHKERRQ(ierr);
857   ierr = RemoveDiscretePressureNullspace_Private(ts, u);CHKERRQ(ierr);
858   PetscFunctionReturn(0);
859 }
860 
861 static void divergence(PetscInt dim, PetscInt Nf, PetscInt NfAux,
862                        const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
863                        const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
864                        PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar divu[])
865 {
866   PetscInt d;
867 
868   divu[0] = 0.;
869   for (d = 0; d < dim; ++d) divu[0] += u_x[d*dim+d];
870 }
871 
872 static PetscErrorCode MonitorError(TS ts, PetscInt step, PetscReal crtime, Vec u, void *ctx)
873 {
874   PetscErrorCode (*exactFuncs[3])(PetscInt dim, PetscReal time, const PetscReal x[], PetscInt Nf, PetscScalar *u, void *ctx);
875   void            *ctxs[3];
876   PetscPointFunc   diagnostics[1] = {divergence};
877   DM               dm, dmCell = ((AppCtx *) ctx)->dmCell;
878   PetscDS          ds;
879   Vec              v, divu;
880   PetscReal        ferrors[3], massFlux;
881   PetscInt         f;
882   PetscErrorCode   ierr;
883 
884   PetscFunctionBeginUser;
885   ierr = TSGetDM(ts, &dm);CHKERRQ(ierr);
886   ierr = DMGetDS(dm, &ds);CHKERRQ(ierr);
887 
888   for (f = 0; f < 3; ++f) {ierr = PetscDSGetExactSolution(ds, f, &exactFuncs[f], &ctxs[f]);CHKERRQ(ierr);}
889   ierr = DMComputeL2FieldDiff(dm, crtime, exactFuncs, ctxs, u, ferrors);CHKERRQ(ierr);
890   ierr = DMGetGlobalVector(dmCell, &divu);CHKERRQ(ierr);
891   ierr = DMProjectField(dmCell, crtime, u, diagnostics, INSERT_VALUES, divu);CHKERRQ(ierr);
892   ierr = VecViewFromOptions(divu, NULL, "-divu_vec_view");CHKERRQ(ierr);
893   ierr = VecNorm(divu, NORM_2, &massFlux);CHKERRQ(ierr);
894   ierr = PetscPrintf(PETSC_COMM_WORLD, "Timestep: %04d time = %-8.4g \t L_2 Error: [%2.3g, %2.3g, %2.3g] ||div u||: %2.3g\n", (int) step, (double) crtime, (double) ferrors[0], (double) ferrors[1], (double) ferrors[2], (double) massFlux);CHKERRQ(ierr);
895 
896   ierr = VecViewFromOptions(u, NULL, "-sol_vec_view");CHKERRQ(ierr);
897 
898   ierr = DMGetGlobalVector(dm, &v);CHKERRQ(ierr);
899   ierr = DMProjectFunction(dm, crtime, exactFuncs, ctxs, INSERT_ALL_VALUES, v);CHKERRQ(ierr);
900   ierr = PetscObjectSetName((PetscObject) v, "Exact Solution");CHKERRQ(ierr);
901   ierr = VecViewFromOptions(v, NULL, "-exact_vec_view");CHKERRQ(ierr);
902   ierr = DMRestoreGlobalVector(dm, &v);CHKERRQ(ierr);
903 
904   ierr = VecViewFromOptions(divu, NULL, "-div_vec_view");CHKERRQ(ierr);
905   ierr = DMRestoreGlobalVector(dmCell, &divu);CHKERRQ(ierr);
906 
907   PetscFunctionReturn(0);
908 }
909 
910 int main(int argc, char **argv)
911 {
912   DM              dm;   /* problem definition */
913   TS              ts;   /* timestepper */
914   Vec             u;    /* solution */
915   AppCtx          user; /* user-defined work context */
916   PetscReal       t;
917   PetscErrorCode  ierr;
918 
919   ierr = PetscInitialize(&argc, &argv, NULL,help);if (ierr) return ierr;
920   ierr = ProcessOptions(PETSC_COMM_WORLD, &user);CHKERRQ(ierr);
921   ierr = PetscBagCreate(PETSC_COMM_WORLD, sizeof(Parameter), &user.bag);CHKERRQ(ierr);
922   ierr = SetupParameters(&user);CHKERRQ(ierr);
923   ierr = TSCreate(PETSC_COMM_WORLD, &ts);CHKERRQ(ierr);
924   ierr = CreateMesh(PETSC_COMM_WORLD, &user, &dm);CHKERRQ(ierr);
925   ierr = TSSetDM(ts, dm);CHKERRQ(ierr);
926   ierr = DMSetApplicationContext(dm, &user);CHKERRQ(ierr);
927   /* Setup problem */
928   ierr = SetupDiscretization(dm, &user);CHKERRQ(ierr);
929   ierr = DMPlexCreateClosureIndex(dm, NULL);CHKERRQ(ierr);
930 
931   ierr = DMCreateGlobalVector(dm, &u);CHKERRQ(ierr);
932   ierr = PetscObjectSetName((PetscObject) u, "Numerical Solution");CHKERRQ(ierr);
933   ierr = DMSetNullSpaceConstructor(dm, 1, CreatePressureNullSpace);CHKERRQ(ierr);
934 
935   ierr = DMTSSetBoundaryLocal(dm, DMPlexTSComputeBoundary, &user);CHKERRQ(ierr);
936   ierr = DMTSSetIFunctionLocal(dm, DMPlexTSComputeIFunctionFEM, &user);CHKERRQ(ierr);
937   ierr = DMTSSetIJacobianLocal(dm, DMPlexTSComputeIJacobianFEM, &user);CHKERRQ(ierr);
938   ierr = TSSetExactFinalTime(ts, TS_EXACTFINALTIME_MATCHSTEP);CHKERRQ(ierr);
939   ierr = TSSetPreStep(ts, RemoveDiscretePressureNullspace);CHKERRQ(ierr);
940   ierr = TSSetFromOptions(ts);CHKERRQ(ierr);
941 
942   ierr = TSSetComputeInitialCondition(ts, SetInitialConditions);CHKERRQ(ierr); /* Must come after SetFromOptions() */
943   ierr = SetInitialConditions(ts, u);CHKERRQ(ierr);
944   ierr = TSGetTime(ts, &t);CHKERRQ(ierr);
945   ierr = DMSetOutputSequenceNumber(dm, 0, t);CHKERRQ(ierr);
946   ierr = DMTSCheckFromOptions(ts, u);CHKERRQ(ierr);
947   ierr = TSMonitorSet(ts, MonitorError, &user, NULL);CHKERRQ(ierr);CHKERRQ(ierr);
948 
949   ierr = TSSolve(ts, u);CHKERRQ(ierr);
950   ierr = DMTSCheckFromOptions(ts, u);CHKERRQ(ierr);
951 
952   ierr = VecDestroy(&u);CHKERRQ(ierr);
953   ierr = DMDestroy(&user.dmCell);CHKERRQ(ierr);
954   ierr = DMDestroy(&dm);CHKERRQ(ierr);
955   ierr = TSDestroy(&ts);CHKERRQ(ierr);
956   ierr = PetscBagDestroy(&user.bag);CHKERRQ(ierr);
957   ierr = PetscFinalize();
958   return ierr;
959 }
960 
961 /*TEST
962 
963   test:
964     suffix: 2d_tri_p2_p1_p1
965     requires: triangle !single
966     args: -dm_plex_separate_marker -sol_type quadratic -dm_refine 0 \
967       -vel_petscspace_degree 2 -pres_petscspace_degree 1 -temp_petscspace_degree 1 \
968       -div_petscdualspace_lagrange_use_moments -div_petscdualspace_lagrange_moment_order 3 \
969       -dmts_check .001 -ts_max_steps 4 -ts_dt 0.1 \
970       -ksp_type fgmres -ksp_gmres_restart 10 -ksp_rtol 1.0e-9 -ksp_error_if_not_converged \
971       -pc_type fieldsplit -pc_fieldsplit_0_fields 0,2 -pc_fieldsplit_1_fields 1 -pc_fieldsplit_type schur -pc_fieldsplit_schur_factorization_type full \
972         -fieldsplit_0_pc_type lu \
973         -fieldsplit_pressure_ksp_rtol 1e-10 -fieldsplit_pressure_pc_type jacobi
974 
975   # TODO Need trig t for convergence in time, also need to refine in space
976   test:
977     # Using -dm_refine 5 -convest_num_refine 2 gives L_2 convergence rate: [0.89, 0.011, 1.0]
978     suffix: 2d_tri_p2_p1_p1_tconv
979     requires: triangle !single
980     args: -dm_plex_separate_marker -sol_type cubic_trig -dm_refine 0 \
981       -vel_petscspace_degree 2 -pres_petscspace_degree 1 -temp_petscspace_degree 1 \
982       -div_petscdualspace_lagrange_use_moments -div_petscdualspace_lagrange_moment_order 3 \
983       -ts_max_steps 4 -ts_dt 0.1 -ts_convergence_estimate -convest_num_refine 1 \
984       -snes_error_if_not_converged -snes_convergence_test correct_pressure \
985       -ksp_type fgmres -ksp_gmres_restart 10 -ksp_rtol 1.0e-9 -ksp_error_if_not_converged \
986       -pc_type fieldsplit -pc_fieldsplit_0_fields 0,2 -pc_fieldsplit_1_fields 1 -pc_fieldsplit_type schur -pc_fieldsplit_schur_factorization_type full \
987         -fieldsplit_0_pc_type lu \
988         -fieldsplit_pressure_ksp_rtol 1e-10 -fieldsplit_pressure_pc_type jacobi
989 
990   test:
991     # Using -dm_refine 3 -convest_num_refine 3 gives L_2 convergence rate: [3.0, 2.5, 1.9]
992     suffix: 2d_tri_p2_p1_p1_sconv
993     requires: triangle !single
994     args: -dm_plex_separate_marker -sol_type cubic -dm_refine 0 \
995       -vel_petscspace_degree 2 -pres_petscspace_degree 1 -temp_petscspace_degree 1 \
996       -div_petscdualspace_lagrange_use_moments -div_petscdualspace_lagrange_moment_order 3 \
997       -ts_max_steps 1 -ts_dt 1e-4 -ts_convergence_estimate -ts_convergence_temporal 0 -convest_num_refine 1 \
998       -snes_error_if_not_converged -snes_convergence_test correct_pressure \
999       -ksp_type fgmres -ksp_gmres_restart 10 -ksp_rtol 1.0e-9 -ksp_atol 1e-16 -ksp_error_if_not_converged \
1000       -pc_type fieldsplit -pc_fieldsplit_0_fields 0,2 -pc_fieldsplit_1_fields 1 -pc_fieldsplit_type schur -pc_fieldsplit_schur_factorization_type full \
1001         -fieldsplit_0_pc_type lu \
1002         -fieldsplit_pressure_ksp_rtol 1e-10 -fieldsplit_pressure_pc_type jacobi
1003 
1004   test:
1005     suffix: 2d_tri_p3_p2_p2
1006     requires: triangle !single
1007     args: -dm_plex_separate_marker -sol_type cubic -dm_refine 0 \
1008       -vel_petscspace_degree 3 -pres_petscspace_degree 2 -temp_petscspace_degree 2 \
1009       -div_petscdualspace_lagrange_use_moments -div_petscdualspace_lagrange_moment_order 3 \
1010       -dmts_check .001 -ts_max_steps 4 -ts_dt 0.1 \
1011       -snes_convergence_test correct_pressure \
1012       -ksp_type fgmres -ksp_gmres_restart 10 -ksp_rtol 1.0e-9 -ksp_error_if_not_converged \
1013       -pc_type fieldsplit -pc_fieldsplit_0_fields 0,2 -pc_fieldsplit_1_fields 1 -pc_fieldsplit_type schur -pc_fieldsplit_schur_factorization_type full \
1014         -fieldsplit_0_pc_type lu \
1015         -fieldsplit_pressure_ksp_rtol 1e-10 -fieldsplit_pressure_pc_type jacobi
1016 
1017   test:
1018     # Using -dm_refine 3 -convest_num_refine 3 gives L_2 convergence rate: [3.0, 2.1, 3.1]
1019     suffix: 2d_tri_p2_p1_p1_tg_sconv
1020     requires: triangle !single
1021     args: -dm_plex_separate_marker -sol_type taylor_green -dm_refine 0 \
1022       -vel_petscspace_degree 2 -pres_petscspace_degree 1 -temp_petscspace_degree 1 \
1023       -div_petscdualspace_lagrange_use_moments -div_petscdualspace_lagrange_moment_order 3 \
1024       -ts_max_steps 1 -ts_dt 1e-8 -ts_convergence_estimate -ts_convergence_temporal 0 -convest_num_refine 1 \
1025       -snes_error_if_not_converged -snes_convergence_test correct_pressure \
1026       -ksp_type fgmres -ksp_gmres_restart 10 -ksp_rtol 1.0e-9 -ksp_atol 1e-16 -ksp_error_if_not_converged \
1027       -pc_type fieldsplit -pc_fieldsplit_0_fields 0,2 -pc_fieldsplit_1_fields 1 -pc_fieldsplit_type schur -pc_fieldsplit_schur_factorization_type full \
1028         -fieldsplit_0_pc_type lu \
1029         -fieldsplit_pressure_ksp_rtol 1e-10 -fieldsplit_pressure_pc_type jacobi
1030 
1031   test:
1032     # Using -dm_refine 3 -convest_num_refine 2 gives L_2 convergence rate: [1.2, 1.5, 1.2]
1033     suffix: 2d_tri_p2_p1_p1_tg_tconv
1034     requires: triangle !single
1035     args: -dm_plex_separate_marker -sol_type taylor_green -dm_refine 0 \
1036       -vel_petscspace_degree 2 -pres_petscspace_degree 1 -temp_petscspace_degree 1 \
1037       -div_petscdualspace_lagrange_use_moments -div_petscdualspace_lagrange_moment_order 3 \
1038       -ts_max_steps 4 -ts_dt 0.1 -ts_convergence_estimate -convest_num_refine 1 \
1039       -snes_error_if_not_converged -snes_convergence_test correct_pressure \
1040       -ksp_type fgmres -ksp_gmres_restart 10 -ksp_rtol 1.0e-9 -ksp_atol 1e-16 -ksp_error_if_not_converged \
1041       -pc_type fieldsplit -pc_fieldsplit_0_fields 0,2 -pc_fieldsplit_1_fields 1 -pc_fieldsplit_type schur -pc_fieldsplit_schur_factorization_type full \
1042         -fieldsplit_0_pc_type lu \
1043         -fieldsplit_pressure_ksp_rtol 1e-10 -fieldsplit_pressure_pc_type jacobi
1044 
1045 TEST*/
1046