xref: /petsc/src/ts/tutorials/ex76.c (revision 4e278199b78715991f5c71ebbd945c1489263e6c)
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 static void f0_cubic_v(PetscInt dim, PetscInt Nf, PetscInt NfAux,
197                        const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
198                        const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
199                        PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
200 {
201   PetscInt                   c, d;
202   PetscInt                   Nc = dim;
203   const PetscReal            nu = PetscRealPart(constants[0]);
204 
205   for (d=0; d<dim; ++d) f0[d] = u_t[uOff[0]+d];
206 
207   for (c=0; c<Nc; ++c) {
208     for (d=0; d<dim; ++d) f0[c] += u[d]*u_x[c*dim+d];
209   }
210   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);
211   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);
212 }
213 
214 static void f0_cubic_w(PetscInt dim, PetscInt Nf, PetscInt NfAux,
215                        const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
216                        const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
217                        PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
218 {
219   PetscInt              d;
220   const PetscReal alpha = PetscRealPart(constants[1]);
221 
222   for (d = 0, f0[0] = 0; d < dim; ++d) f0[0] += u[uOff[0]+d]*u_x[uOff_x[2]+d];
223   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);
224 }
225 
226 /*
227   CASE: cubic-trigonometric
228   In 2D we use exact solution:
229 
230     u = beta cos t + x^3 + y^3
231     v = beta sin t + 2x^3 - 3x^2y
232     p = 3/2 x^2 + 3/2 y^2 - 1
233     T = 20 cos t + 1/2 x^2 + 1/2 y^2
234     f = < beta cos t 3x^2         + beta sin t (3y^2 - 1) + 3x^5 + 6x^3y^2 - 6x^2y^3 - \nu(6x + 6y)  + 3x,
235           beta cos t (6x^2 - 6xy) - beta sin t (3x^2)     + 3x^4y + 6x^2y^3 - 6xy^4  - \nu(12x - 6y) + 3y>
236     Q = beta cos t x + beta sin t (y - 1) + x^4 + 2x^3y - 3x^2y^2 + xy^3 - 2\alpha
237 
238   so that
239 
240     \nabla \cdot u = 3x^2 - 3x^2 = 0
241 
242   f = du/dt + u \cdot \nabla u - \nu \Delta u + \nabla p
243     = <-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>
244     = <-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>
245     = <cos t (3x^2)       + sin t (3y^2 - 1) + 3x^5 + 6x^3y^2 - 6x^2y^3 - \nu (6x + 6y)  + 3x,
246        cos t (6x^2 - 6xy) - sin t (3x^2)     + 3x^4y + 6x^2y^3 - 6xy^4  - \nu (12x - 6y) + 3y>
247 
248   Q = dT/dt + u \cdot \nabla T - \alpha \Delta T
249     = -sin t + <cos t + x^3 + y^3, sin t + 2x^3 - 3x^2y> . <x, y> - 2 \alpha
250     = -sin t + cos t (x) + x^4 + xy^3 + sin t (y) + 2x^3y - 3x^2y^2 - 2 \alpha
251     = cos t x + sin t (y - 1) + (x^4 + 2x^3y - 3x^2y^2 + xy^3 - 2 \alpha)
252 */
253 static PetscErrorCode cubic_trig_u(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *u, void *ctx)
254 {
255   u[0] = 100.*PetscCosReal(time) + X[0]*X[0]*X[0] + X[1]*X[1]*X[1];
256   u[1] = 100.*PetscSinReal(time) + 2.0*X[0]*X[0]*X[0] - 3.0*X[0]*X[0]*X[1];
257   return 0;
258 }
259 static PetscErrorCode cubic_trig_u_t(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *u, void *ctx)
260 {
261   u[0] = -100.*PetscSinReal(time);
262   u[1] =  100.*PetscCosReal(time);
263   return 0;
264 }
265 
266 static PetscErrorCode cubic_trig_p(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *p, void *ctx)
267 {
268   p[0] = 3.0*X[0]*X[0]/2.0 + 3.0*X[1]*X[1]/2.0 - 1.0;
269   return 0;
270 }
271 
272 static PetscErrorCode cubic_trig_T(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *T, void *ctx)
273 {
274   T[0] = 100.*PetscCosReal(time) + X[0]*X[0]/2.0 + X[1]*X[1]/2.0;
275   return 0;
276 }
277 static PetscErrorCode cubic_trig_T_t(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *T, void *ctx)
278 {
279   T[0] = -100.*PetscSinReal(time);
280   return 0;
281 }
282 
283 static void f0_cubic_trig_v(PetscInt dim, PetscInt Nf, PetscInt NfAux,
284                             const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
285                             const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
286                             PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
287 {
288   const PetscReal nu = PetscRealPart(constants[0]);
289   PetscInt        Nc = dim;
290   PetscInt        c, d;
291 
292   for (d = 0; d < dim; ++d) f0[d] = u_t[uOff[0]+d];
293 
294   for (c = 0; c < Nc; ++c) {
295     for (d = 0; d < dim; ++d) f0[c] += u[d]*u_x[c*dim+d];
296   }
297   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];
298   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];
299 }
300 
301 static void f0_cubic_trig_w(PetscInt dim, PetscInt Nf, PetscInt NfAux,
302                             const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
303                             const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
304                             PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
305 {
306   const PetscReal alpha = PetscRealPart(constants[1]);
307   PetscInt        d;
308 
309   for (d = 0, f0[0] = 0; d < dim; ++d) f0[0] += u[uOff[0]+d]*u_x[uOff_x[2]+d];
310   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);
311 }
312 
313 /*
314   CASE: taylor-green vortex
315   In 2D we use exact solution:
316 
317     u = 1 - cos(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t)
318     v = 1 + sin(\pi(x - t)) cos(\pi(y - t)) exp(-2 \pi^2 \nu t)
319     p = -1/4 [cos(2 \pi(x - t)) + cos(2 \pi(y - t))] exp(-4 \pi^2 \nu t)
320     T = t + x + y
321     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))  >
322     Q = 3 + sin(\pi(x-y)) exp(-2\nu \pi^2 t)
323 
324   so that
325 
326   \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
327 
328   f = du/dt + u \cdot \nabla u - \nu \Delta u + \nabla p
329     = <-\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),
330         \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)>
331     + < \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),
332         \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)>
333     + <-\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),
334        -\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)>
335     + <-2\pi^2 cos(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t),
336         2\pi^2 sin(\pi(x - t)) cos(\pi(y - t)) exp(-2 \pi^2 \nu t)>
337     + < \pi/2 sin(2\pi(x - t)) exp(-4 \pi^2 \nu t),
338         \pi/2 sin(2\pi(y - t)) exp(-4 \pi^2 \nu t)>
339     = <-\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),
340         \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)>
341     + < \pi sin(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t),
342         \pi cos(\pi(x - t)) cos(\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 sin(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t)>
345     + <-\pi/2 sin(2\pi(x - t)) exp(-4 \pi^2 \nu t),
346        -\pi/2 sin(2\pi(y - t)) exp(-4 \pi^2 \nu t)>
347     + <-2\pi^2 cos(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t),
348         2\pi^2 sin(\pi(x - t)) cos(\pi(y - t)) exp(-2 \pi^2 \nu t)>
349     + < \pi/2 sin(2\pi(x - t)) exp(-4 \pi^2 \nu t),
350         \pi/2 sin(2\pi(y - t)) exp(-4 \pi^2 \nu t)>
351     = <-\pi (sin(\pi(x - t)) sin(\pi(y - t)) - cos(\pi(x - t)) cos(\pi(y - t))) exp(-2 \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)) exp(-2 \pi^2 \nu t),
354         \pi cos(\pi(x - t)) cos(\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 sin(\pi(x - t)) sin(\pi(y - t)) exp(-2 \pi^2 \nu t)>
357     = < \pi cos(\pi(x - t)) cos(\pi(y - t)),
358         \pi sin(\pi(x - t)) sin(\pi(y - t))>
359     + <-\pi cos(\pi(x - t)) cos(\pi(y - t)),
360        -\pi sin(\pi(x - t)) sin(\pi(y - t))> = 0
361   Q = dT/dt + u \cdot \nabla T - \alpha \Delta T
362     = 1 + u \cdot <1, 1> - 0
363     = 1 + u + v
364 */
365 
366 static PetscErrorCode taylor_green_u(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *u, void *ctx)
367 {
368   u[0] = 1 - PetscCosReal(PETSC_PI*(X[0]-time))*PetscSinReal(PETSC_PI*(X[1]-time))*PetscExpReal(-2*PETSC_PI*PETSC_PI*time);
369   u[1] = 1 + PetscSinReal(PETSC_PI*(X[0]-time))*PetscCosReal(PETSC_PI*(X[1]-time))*PetscExpReal(-2*PETSC_PI*PETSC_PI*time);
370   return 0;
371 }
372 static PetscErrorCode taylor_green_u_t(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *u, void *ctx)
373 {
374   u[0] = -PETSC_PI*(PetscSinReal(PETSC_PI*(X[0]-time))*PetscSinReal(PETSC_PI*(X[1]-time))
375                   - PetscCosReal(PETSC_PI*(X[0]-time))*PetscCosReal(PETSC_PI*(X[1]-time))
376                   - 2*PETSC_PI*PetscCosReal(PETSC_PI*(X[0]-time))*PetscSinReal(PETSC_PI*(X[1]-time)))*PetscExpReal(-2*PETSC_PI*PETSC_PI*time);
377   u[1] =  PETSC_PI*(PetscSinReal(PETSC_PI*(X[0]-time))*PetscSinReal(PETSC_PI*(X[1]-time))
378                   - PetscCosReal(PETSC_PI*(X[0]-time))*PetscCosReal(PETSC_PI*(X[1]-time))
379                   - 2*PETSC_PI*PetscSinReal(PETSC_PI*(X[0]-time))*PetscCosReal(PETSC_PI*(X[1]-time)))*PetscExpReal(-2*PETSC_PI*PETSC_PI*time);
380   return 0;
381 }
382 
383 static PetscErrorCode taylor_green_p(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *p, void *ctx)
384 {
385   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);
386   return 0;
387 }
388 
389 static PetscErrorCode taylor_green_p_t(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *p, void *ctx)
390 {
391   p[0] = PETSC_PI*(0.5*(PetscSinReal(2*PETSC_PI*(X[0]-time)) + PetscSinReal(2*PETSC_PI*(X[1]-time)))
392                  + PETSC_PI*(PetscCosReal(2*PETSC_PI*(X[0]-time)) + PetscCosReal(2*PETSC_PI*(X[1]-time))))*PetscExpReal(-4*PETSC_PI*PETSC_PI*time);
393   return 0;
394 }
395 
396 static PetscErrorCode taylor_green_T(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *T, void *ctx)
397 {
398   T[0] = time + X[0] + X[1];
399   return 0;
400 }
401 static PetscErrorCode taylor_green_T_t(PetscInt Dim, PetscReal time, const PetscReal X[], PetscInt Nf, PetscScalar *T, void *ctx)
402 {
403   T[0] = 1.0;
404   return 0;
405 }
406 
407 static void f0_taylor_green_v(PetscInt dim, PetscInt Nf, PetscInt NfAux,
408                             const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
409                             const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
410                             PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
411 {
412   PetscInt        Nc = dim;
413   PetscInt        c, d;
414 
415   for (d = 0; d < dim; ++d) f0[d] = u_t[uOff[0]+d];
416 
417   for (c = 0; c < Nc; ++c) {
418     for (d = 0; d < dim; ++d) f0[c] += u[d]*u_x[c*dim+d];
419   }
420 }
421 
422 static void f0_taylor_green_w(PetscInt dim, PetscInt Nf, PetscInt NfAux,
423                             const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
424                             const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
425                             PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
426 {
427   PetscScalar vel[2];
428   PetscInt    d;
429 
430   taylor_green_u(dim, t, X, Nf, vel, NULL);
431   for (d = 0, f0[0] = 0; d < dim; ++d) f0[0] += u[uOff[0]+d]*u_x[uOff_x[2]+d];
432   f0[0] += u_t[uOff[2]] - (1.0 + vel[0] + vel[1]);
433 }
434 
435 static void f0_q(PetscInt dim, PetscInt Nf, PetscInt NfAux,
436                  const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
437                  const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
438                  PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
439 {
440   PetscInt d;
441   for (d = 0, f0[0] = 0.0; d < dim; ++d) f0[0] += u_x[d*dim+d];
442 }
443 
444 /*f1_v = \nu[grad(u) + grad(u)^T] - pI */
445 static void f1_v(PetscInt dim, PetscInt Nf, PetscInt NfAux,
446                  const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
447                  const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
448                  PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f1[])
449 {
450   const PetscReal nu = PetscRealPart(constants[0]);
451   const PetscInt    Nc = dim;
452   PetscInt        c, d;
453 
454   for (c = 0; c < Nc; ++c) {
455     for (d = 0; d < dim; ++d) {
456       f1[c*dim+d] = nu*(u_x[c*dim+d] + u_x[d*dim+c]);
457     }
458     f1[c*dim+c] -= u[uOff[1]];
459   }
460 }
461 
462 static void f1_w(PetscInt dim, PetscInt Nf, PetscInt NfAux,
463                  const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
464                  const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
465                  PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f1[])
466 {
467   const PetscReal alpha = PetscRealPart(constants[1]);
468   PetscInt d;
469   for (d = 0; d < dim; ++d) f1[d] = alpha*u_x[uOff_x[2]+d];
470 }
471 
472 /*Jacobians*/
473 static void g1_qu(PetscInt dim, PetscInt Nf, PetscInt NfAux,
474                  const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
475                  const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
476                  PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g1[])
477 {
478   PetscInt d;
479   for (d = 0; d < dim; ++d) g1[d*dim+d] = 1.0;
480 }
481 
482 static void g0_vu(PetscInt dim, PetscInt Nf, PetscInt NfAux,
483                   const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
484                   const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
485                   PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g0[])
486 {
487   PetscInt c, d;
488   const PetscInt  Nc = dim;
489 
490   for (d = 0; d < dim; ++d) g0[d*dim+d] = u_tShift;
491 
492   for (c = 0; c < Nc; ++c) {
493     for (d = 0; d < dim; ++d) {
494       g0[c*Nc+d] += u_x[ c*Nc+d];
495     }
496   }
497 }
498 
499 static void g1_vu(PetscInt dim, PetscInt Nf, PetscInt NfAux,
500                   const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
501                   const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
502                   PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g1[])
503 {
504   PetscInt NcI = dim;
505   PetscInt NcJ = dim;
506   PetscInt c, d, e;
507 
508   for (c = 0; c < NcI; ++c) {
509     for (d = 0; d < NcJ; ++d) {
510       for (e = 0; e < dim; ++e) {
511         if (c == d) {
512           g1[(c*NcJ+d)*dim+e] += u[e];
513         }
514       }
515     }
516   }
517 }
518 
519 static void g2_vp(PetscInt dim, PetscInt Nf, PetscInt NfAux,
520                   const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
521                   const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
522                   PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g2[])
523 {
524   PetscInt d;
525   for (d = 0; d < dim; ++d) g2[d*dim+d] = -1.0;
526 }
527 
528 static void g3_vu(PetscInt dim, PetscInt Nf, PetscInt NfAux,
529                   const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
530                   const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
531                   PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g3[])
532 {
533    const PetscReal nu = PetscRealPart(constants[0]);
534    const PetscInt  Nc = dim;
535    PetscInt        c, d;
536 
537   for (c = 0; c < Nc; ++c) {
538     for (d = 0; d < dim; ++d) {
539       g3[((c*Nc+c)*dim+d)*dim+d] += nu;
540       g3[((c*Nc+d)*dim+d)*dim+c] += nu;
541     }
542   }
543 }
544 
545 static void g0_wT(PetscInt dim, PetscInt Nf, PetscInt NfAux,
546                   const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
547                   const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
548                   PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g0[])
549 {
550   g0[0] = u_tShift;
551 }
552 
553 static void g0_wu(PetscInt dim, PetscInt Nf, PetscInt NfAux,
554                   const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
555                   const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
556                   PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g0[])
557 {
558   PetscInt d;
559   for (d = 0; d < dim; ++d) g0[d] = u_x[uOff_x[2]+d];
560 }
561 
562 static void g1_wT(PetscInt dim, PetscInt Nf, PetscInt NfAux,
563                   const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
564                   const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
565                   PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g1[])
566 {
567   PetscInt d;
568   for (d = 0; d < dim; ++d) g1[d] = u[uOff[0]+d];
569 }
570 
571 static void g3_wT(PetscInt dim, PetscInt Nf, PetscInt NfAux,
572                   const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
573                   const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
574                   PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g3[])
575 {
576   const PetscReal alpha = PetscRealPart(constants[1]);
577   PetscInt               d;
578 
579   for (d = 0; d < dim; ++d) g3[d*dim+d] = alpha;
580 }
581 
582 static PetscErrorCode ProcessOptions(MPI_Comm comm, AppCtx *options)
583 {
584   PetscInt       sol;
585   PetscErrorCode ierr;
586 
587   PetscFunctionBeginUser;
588   options->solType = SOL_QUADRATIC;
589 
590   ierr = PetscOptionsBegin(comm, "", "Low Mach flow Problem Options", "DMPLEX");CHKERRQ(ierr);
591   sol = options->solType;
592   ierr = PetscOptionsEList("-sol_type", "The solution type", "ex62.c", solTypes, NUM_SOL_TYPES, solTypes[options->solType], &sol, NULL);CHKERRQ(ierr);
593   options->solType = (SolType) sol;
594   ierr = PetscOptionsEnd();
595   PetscFunctionReturn(0);
596 }
597 
598 static PetscErrorCode SetupParameters(AppCtx *user)
599 {
600   PetscBag       bag;
601   Parameter     *p;
602   PetscErrorCode ierr;
603 
604   PetscFunctionBeginUser;
605   /* setup PETSc parameter bag */
606   ierr = PetscBagGetData(user->bag, (void **) &p);CHKERRQ(ierr);
607   ierr = PetscBagSetName(user->bag, "par", "Low Mach flow parameters");CHKERRQ(ierr);
608   bag  = user->bag;
609   ierr = PetscBagRegisterReal(bag, &p->nu,    1.0, "nu",    "Kinematic viscosity");CHKERRQ(ierr);
610   ierr = PetscBagRegisterReal(bag, &p->alpha, 1.0, "alpha", "Thermal diffusivity");CHKERRQ(ierr);
611   ierr = PetscBagRegisterReal(bag, &p->T_in,  1.0, "T_in",  "Inlet temperature");CHKERRQ(ierr);
612   PetscFunctionReturn(0);
613 }
614 
615 static PetscErrorCode CreateMesh(MPI_Comm comm, AppCtx *user, DM *dm)
616 {
617   PetscErrorCode ierr;
618 
619   PetscFunctionBeginUser;
620   ierr = DMCreate(comm, dm);CHKERRQ(ierr);
621   ierr = DMSetType(*dm, DMPLEX);CHKERRQ(ierr);
622   ierr = DMSetFromOptions(*dm);CHKERRQ(ierr);
623   ierr = DMViewFromOptions(*dm, NULL, "-dm_view");CHKERRQ(ierr);
624   PetscFunctionReturn(0);
625 }
626 
627 static PetscErrorCode SetupProblem(DM dm, AppCtx *user)
628 {
629   PetscSimplePointFunc exactFuncs[3];
630   PetscSimplePointFunc exactFuncs_t[3];
631   PetscDS              prob;
632   DMLabel              label;
633   Parameter           *ctx;
634   PetscInt             id;
635   PetscErrorCode       ierr;
636 
637   PetscFunctionBeginUser;
638   ierr = DMGetLabel(dm, "marker", &label);CHKERRQ(ierr);
639   ierr = DMGetDS(dm, &prob);CHKERRQ(ierr);
640   switch(user->solType){
641   case SOL_QUADRATIC:
642     ierr = PetscDSSetResidual(prob, 0, f0_quadratic_v, f1_v);CHKERRQ(ierr);
643     ierr = PetscDSSetResidual(prob, 2, f0_quadratic_w, f1_w);CHKERRQ(ierr);
644 
645     exactFuncs[0]   = quadratic_u;
646     exactFuncs[1]   = quadratic_p;
647     exactFuncs[2]   = quadratic_T;
648     exactFuncs_t[0] = quadratic_u_t;
649     exactFuncs_t[1] = NULL;
650     exactFuncs_t[2] = quadratic_T_t;
651     break;
652   case SOL_CUBIC:
653     ierr = PetscDSSetResidual(prob, 0, f0_cubic_v, f1_v);CHKERRQ(ierr);
654     ierr = PetscDSSetResidual(prob, 2, f0_cubic_w, f1_w);CHKERRQ(ierr);
655 
656     exactFuncs[0]   = cubic_u;
657     exactFuncs[1]   = cubic_p;
658     exactFuncs[2]   = cubic_T;
659     exactFuncs_t[0] = cubic_u_t;
660     exactFuncs_t[1] = NULL;
661     exactFuncs_t[2] = cubic_T_t;
662     break;
663   case SOL_CUBIC_TRIG:
664     ierr = PetscDSSetResidual(prob, 0, f0_cubic_trig_v, f1_v);CHKERRQ(ierr);
665     ierr = PetscDSSetResidual(prob, 2, f0_cubic_trig_w, f1_w);CHKERRQ(ierr);
666 
667     exactFuncs[0]   = cubic_trig_u;
668     exactFuncs[1]   = cubic_trig_p;
669     exactFuncs[2]   = cubic_trig_T;
670     exactFuncs_t[0] = cubic_trig_u_t;
671     exactFuncs_t[1] = NULL;
672     exactFuncs_t[2] = cubic_trig_T_t;
673     break;
674   case SOL_TAYLOR_GREEN:
675     ierr = PetscDSSetResidual(prob, 0, f0_taylor_green_v, f1_v);CHKERRQ(ierr);
676     ierr = PetscDSSetResidual(prob, 2, f0_taylor_green_w, f1_w);CHKERRQ(ierr);
677 
678     exactFuncs[0]   = taylor_green_u;
679     exactFuncs[1]   = taylor_green_p;
680     exactFuncs[2]   = taylor_green_T;
681     exactFuncs_t[0] = taylor_green_u_t;
682     exactFuncs_t[1] = taylor_green_p_t;
683     exactFuncs_t[2] = taylor_green_T_t;
684     break;
685    default: SETERRQ2(PetscObjectComm((PetscObject) prob), PETSC_ERR_ARG_WRONG, "Unsupported solution type: %s (%D)", solTypes[PetscMin(user->solType, NUM_SOL_TYPES)], user->solType);
686   }
687 
688   ierr = PetscDSSetResidual(prob, 1, f0_q, NULL);CHKERRQ(ierr);
689 
690   ierr = PetscDSSetJacobian(prob, 0, 0, g0_vu, g1_vu,  NULL,  g3_vu);CHKERRQ(ierr);
691   ierr = PetscDSSetJacobian(prob, 0, 1, NULL, NULL,  g2_vp, NULL);CHKERRQ(ierr);
692   ierr = PetscDSSetJacobian(prob, 1, 0, NULL, g1_qu, NULL,  NULL);CHKERRQ(ierr);
693   ierr = PetscDSSetJacobian(prob, 2, 0, g0_wu, NULL, NULL,  NULL);CHKERRQ(ierr);
694   ierr = PetscDSSetJacobian(prob, 2, 2, g0_wT, g1_wT, NULL,  g3_wT);CHKERRQ(ierr);
695   /* Setup constants */
696   {
697     Parameter  *param;
698     PetscScalar constants[3];
699 
700     ierr = PetscBagGetData(user->bag, (void **) &param);CHKERRQ(ierr);
701 
702     constants[0] = param->nu;
703     constants[1] = param->alpha;
704     constants[2] = param->T_in;
705     ierr = PetscDSSetConstants(prob, 3, constants);CHKERRQ(ierr);
706   }
707   /* Setup Boundary Conditions */
708   ierr = PetscBagGetData(user->bag, (void **) &ctx);CHKERRQ(ierr);
709   id   = 3;
710   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);
711   id   = 1;
712   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);
713   id   = 2;
714   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);
715   id   = 4;
716   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);
717   id   = 3;
718   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);
719   id   = 1;
720   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);
721   id   = 2;
722   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);
723   id   = 4;
724   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);
725 
726   /*setup exact solution.*/
727   ierr = PetscDSSetExactSolution(prob, 0, exactFuncs[0], ctx);CHKERRQ(ierr);
728   ierr = PetscDSSetExactSolution(prob, 1, exactFuncs[1], ctx);CHKERRQ(ierr);
729   ierr = PetscDSSetExactSolution(prob, 2, exactFuncs[2], ctx);CHKERRQ(ierr);
730   ierr = PetscDSSetExactSolutionTimeDerivative(prob, 0, exactFuncs_t[0], ctx);CHKERRQ(ierr);
731   ierr = PetscDSSetExactSolutionTimeDerivative(prob, 1, exactFuncs_t[1], ctx);CHKERRQ(ierr);
732   ierr = PetscDSSetExactSolutionTimeDerivative(prob, 2, exactFuncs_t[2], ctx);CHKERRQ(ierr);
733   PetscFunctionReturn(0);
734 }
735 
736 static PetscErrorCode SetupDiscretization(DM dm, AppCtx *user)
737 {
738   DM              cdm   = dm;
739   PetscFE         fe[3], fediv;
740   Parameter      *param;
741   DMPolytopeType  ct;
742   PetscInt        dim, cStart;
743   PetscBool       simplex;
744   PetscErrorCode  ierr;
745 
746   PetscFunctionBeginUser;
747   ierr = DMGetDimension(dm, &dim);CHKERRQ(ierr);
748   ierr = DMPlexGetHeightStratum(dm, 0, &cStart, NULL);CHKERRQ(ierr);
749   ierr = DMPlexGetCellType(dm, cStart, &ct);CHKERRQ(ierr);
750   simplex = DMPolytopeTypeGetNumVertices(ct) == DMPolytopeTypeGetDim(ct)+1 ? PETSC_TRUE : PETSC_FALSE;
751   /* Create finite element */
752   ierr = PetscFECreateDefault(PETSC_COMM_SELF, dim, dim, simplex, "vel_", PETSC_DEFAULT, &fe[0]);CHKERRQ(ierr);
753   ierr = PetscObjectSetName((PetscObject) fe[0], "velocity");CHKERRQ(ierr);
754 
755   ierr = PetscFECreateDefault(PETSC_COMM_SELF, dim, 1, simplex, "pres_", PETSC_DEFAULT, &fe[1]);CHKERRQ(ierr);
756   ierr = PetscFECopyQuadrature(fe[0], fe[1]);CHKERRQ(ierr);
757   ierr = PetscObjectSetName((PetscObject) fe[1], "pressure");CHKERRQ(ierr);
758 
759   ierr = PetscFECreateDefault(PETSC_COMM_SELF, dim, 1, simplex, "temp_", PETSC_DEFAULT, &fe[2]);CHKERRQ(ierr);
760   ierr = PetscFECopyQuadrature(fe[0], fe[2]);CHKERRQ(ierr);
761   ierr = PetscObjectSetName((PetscObject) fe[2], "temperature");CHKERRQ(ierr);
762 
763   ierr = PetscFECreateDefault(PETSC_COMM_SELF, dim, 1, simplex, "div_", PETSC_DEFAULT, &fediv);CHKERRQ(ierr);
764   ierr = PetscFECopyQuadrature(fe[0], fediv);CHKERRQ(ierr);
765   ierr = PetscObjectSetName((PetscObject) fediv, "divergence");CHKERRQ(ierr);
766 
767   /* Set discretization and boundary conditions for each mesh */
768   ierr = DMSetField(dm, 0, NULL, (PetscObject) fe[0]);CHKERRQ(ierr);
769   ierr = DMSetField(dm, 1, NULL, (PetscObject) fe[1]);CHKERRQ(ierr);
770   ierr = DMSetField(dm, 2, NULL, (PetscObject) fe[2]);CHKERRQ(ierr);
771   ierr = DMCreateDS(dm);CHKERRQ(ierr);
772   ierr = SetupProblem(dm, user);CHKERRQ(ierr);
773   ierr = PetscBagGetData(user->bag, (void **) &param);CHKERRQ(ierr);
774   while (cdm) {
775     ierr = DMCopyDisc(dm, cdm);CHKERRQ(ierr);
776     ierr = DMGetCoarseDM(cdm, &cdm);CHKERRQ(ierr);
777   }
778   ierr = PetscFEDestroy(&fe[0]);CHKERRQ(ierr);
779   ierr = PetscFEDestroy(&fe[1]);CHKERRQ(ierr);
780   ierr = PetscFEDestroy(&fe[2]);CHKERRQ(ierr);
781 
782   ierr = DMClone(dm, &user->dmCell);CHKERRQ(ierr);
783   ierr = DMSetField(user->dmCell, 0, NULL, (PetscObject) fediv);CHKERRQ(ierr);
784   ierr = DMCreateDS(user->dmCell);CHKERRQ(ierr);
785   ierr = PetscFEDestroy(&fediv);CHKERRQ(ierr);
786 
787   {
788     PetscObject  pressure;
789     MatNullSpace nullspacePres;
790 
791     ierr = DMGetField(dm, 1, NULL, &pressure);CHKERRQ(ierr);
792     ierr = MatNullSpaceCreate(PetscObjectComm(pressure), PETSC_TRUE, 0, NULL, &nullspacePres);CHKERRQ(ierr);
793     ierr = PetscObjectCompose(pressure, "nullspace", (PetscObject) nullspacePres);CHKERRQ(ierr);
794     ierr = MatNullSpaceDestroy(&nullspacePres);CHKERRQ(ierr);
795   }
796 
797   PetscFunctionReturn(0);
798 }
799 
800 static PetscErrorCode CreatePressureNullSpace(DM dm, PetscInt ofield, PetscInt nfield, MatNullSpace *nullSpace)
801 {
802   Vec              vec;
803   PetscErrorCode (*funcs[3])(PetscInt, PetscReal, const PetscReal[], PetscInt, PetscScalar *, void *) = {zero, zero, zero};
804   PetscErrorCode   ierr;
805 
806   PetscFunctionBeginUser;
807   if (ofield != 1) SETERRQ1(PetscObjectComm((PetscObject) dm), PETSC_ERR_ARG_WRONG, "Nullspace must be for pressure field at index 1, not %D", ofield);
808   funcs[nfield] = constant;
809   ierr = DMCreateGlobalVector(dm, &vec);CHKERRQ(ierr);
810   ierr = DMProjectFunction(dm, 0.0, funcs, NULL, INSERT_ALL_VALUES, vec);CHKERRQ(ierr);
811   ierr = VecNormalize(vec, NULL);CHKERRQ(ierr);
812   ierr = PetscObjectSetName((PetscObject) vec, "Pressure Null Space");CHKERRQ(ierr);
813   ierr = VecViewFromOptions(vec, NULL, "-pressure_nullspace_view");CHKERRQ(ierr);
814   ierr = MatNullSpaceCreate(PetscObjectComm((PetscObject) dm), PETSC_FALSE, 1, &vec, nullSpace);CHKERRQ(ierr);
815   ierr = VecDestroy(&vec);CHKERRQ(ierr);
816   PetscFunctionReturn(0);
817 }
818 
819 static PetscErrorCode RemoveDiscretePressureNullspace_Private(TS ts, Vec u)
820 {
821   DM             dm;
822   MatNullSpace   nullsp;
823   PetscErrorCode ierr;
824 
825   PetscFunctionBegin;
826   ierr = TSGetDM(ts, &dm);CHKERRQ(ierr);
827   ierr = CreatePressureNullSpace(dm, 1, 1, &nullsp);CHKERRQ(ierr);
828   ierr = MatNullSpaceRemove(nullsp, u);CHKERRQ(ierr);
829   ierr = MatNullSpaceDestroy(&nullsp);CHKERRQ(ierr);
830   PetscFunctionReturn(0);
831 }
832 
833 /* Make the discrete pressure discretely divergence free */
834 static PetscErrorCode RemoveDiscretePressureNullspace(TS ts)
835 {
836   Vec            u;
837   PetscErrorCode ierr;
838 
839   PetscFunctionBegin;
840   ierr = TSGetSolution(ts, &u);CHKERRQ(ierr);
841   ierr = RemoveDiscretePressureNullspace_Private(ts, u);CHKERRQ(ierr);
842   PetscFunctionReturn(0);
843 }
844 
845 static PetscErrorCode SetInitialConditions(TS ts, Vec u)
846 {
847   DM             dm;
848   PetscReal      t;
849   PetscErrorCode ierr;
850 
851   PetscFunctionBegin;
852   ierr = TSGetDM(ts, &dm);CHKERRQ(ierr);
853   ierr = TSGetTime(ts, &t);CHKERRQ(ierr);
854   ierr = DMComputeExactSolution(dm, t, u, NULL);CHKERRQ(ierr);
855   ierr = RemoveDiscretePressureNullspace_Private(ts, u);CHKERRQ(ierr);
856   PetscFunctionReturn(0);
857 }
858 
859 static void divergence(PetscInt dim, PetscInt Nf, PetscInt NfAux,
860                        const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
861                        const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
862                        PetscReal t, const PetscReal X[], PetscInt numConstants, const PetscScalar constants[], PetscScalar divu[])
863 {
864   PetscInt d;
865 
866   divu[0] = 0.;
867   for (d = 0; d < dim; ++d) divu[0] += u_x[d*dim+d];
868 }
869 
870 static PetscErrorCode MonitorError(TS ts, PetscInt step, PetscReal crtime, Vec u, void *ctx)
871 {
872   PetscErrorCode (*exactFuncs[3])(PetscInt dim, PetscReal time, const PetscReal x[], PetscInt Nf, PetscScalar *u, void *ctx);
873   void            *ctxs[3];
874   PetscPointFunc   diagnostics[1] = {divergence};
875   DM               dm, dmCell = ((AppCtx *) ctx)->dmCell;
876   PetscDS          ds;
877   Vec              v, divu;
878   PetscReal        ferrors[3], massFlux;
879   PetscInt         f;
880   PetscErrorCode   ierr;
881 
882   PetscFunctionBeginUser;
883   ierr = TSGetDM(ts, &dm);CHKERRQ(ierr);
884   ierr = DMGetDS(dm, &ds);CHKERRQ(ierr);
885 
886   for (f = 0; f < 3; ++f) {ierr = PetscDSGetExactSolution(ds, f, &exactFuncs[f], &ctxs[f]);CHKERRQ(ierr);}
887   ierr = DMComputeL2FieldDiff(dm, crtime, exactFuncs, ctxs, u, ferrors);CHKERRQ(ierr);
888   ierr = DMGetGlobalVector(dmCell, &divu);CHKERRQ(ierr);
889   ierr = DMProjectField(dmCell, crtime, u, diagnostics, INSERT_VALUES, divu);CHKERRQ(ierr);
890   ierr = VecViewFromOptions(divu, NULL, "-divu_vec_view");CHKERRQ(ierr);
891   ierr = VecNorm(divu, NORM_2, &massFlux);CHKERRQ(ierr);
892   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);
893 
894   ierr = VecViewFromOptions(u, NULL, "-sol_vec_view");CHKERRQ(ierr);
895 
896   ierr = DMGetGlobalVector(dm, &v);CHKERRQ(ierr);
897   ierr = DMProjectFunction(dm, crtime, exactFuncs, ctxs, INSERT_ALL_VALUES, v);CHKERRQ(ierr);
898   ierr = PetscObjectSetName((PetscObject) v, "Exact Solution");CHKERRQ(ierr);
899   ierr = VecViewFromOptions(v, NULL, "-exact_vec_view");CHKERRQ(ierr);
900   ierr = DMRestoreGlobalVector(dm, &v);CHKERRQ(ierr);
901 
902   ierr = VecViewFromOptions(divu, NULL, "-div_vec_view");CHKERRQ(ierr);
903   ierr = DMRestoreGlobalVector(dmCell, &divu);CHKERRQ(ierr);
904 
905   PetscFunctionReturn(0);
906 }
907 
908 int main(int argc, char **argv)
909 {
910   DM              dm;   /* problem definition */
911   TS              ts;   /* timestepper */
912   Vec             u;    /* solution */
913   AppCtx          user; /* user-defined work context */
914   PetscReal       t;
915   PetscErrorCode  ierr;
916 
917   ierr = PetscInitialize(&argc, &argv, NULL,help);if (ierr) return ierr;
918   ierr = ProcessOptions(PETSC_COMM_WORLD, &user);CHKERRQ(ierr);
919   ierr = PetscBagCreate(PETSC_COMM_WORLD, sizeof(Parameter), &user.bag);CHKERRQ(ierr);
920   ierr = SetupParameters(&user);CHKERRQ(ierr);
921   ierr = TSCreate(PETSC_COMM_WORLD, &ts);CHKERRQ(ierr);
922   ierr = CreateMesh(PETSC_COMM_WORLD, &user, &dm);CHKERRQ(ierr);
923   ierr = TSSetDM(ts, dm);CHKERRQ(ierr);
924   ierr = DMSetApplicationContext(dm, &user);CHKERRQ(ierr);
925   /* Setup problem */
926   ierr = SetupDiscretization(dm, &user);CHKERRQ(ierr);
927   ierr = DMPlexCreateClosureIndex(dm, NULL);CHKERRQ(ierr);
928 
929   ierr = DMCreateGlobalVector(dm, &u);CHKERRQ(ierr);
930   ierr = PetscObjectSetName((PetscObject) u, "Numerical Solution");CHKERRQ(ierr);
931   ierr = DMSetNullSpaceConstructor(dm, 1, CreatePressureNullSpace);CHKERRQ(ierr);
932 
933   ierr = DMTSSetBoundaryLocal(dm, DMPlexTSComputeBoundary, &user);CHKERRQ(ierr);
934   ierr = DMTSSetIFunctionLocal(dm, DMPlexTSComputeIFunctionFEM, &user);CHKERRQ(ierr);
935   ierr = DMTSSetIJacobianLocal(dm, DMPlexTSComputeIJacobianFEM, &user);CHKERRQ(ierr);
936   ierr = TSSetExactFinalTime(ts, TS_EXACTFINALTIME_MATCHSTEP);CHKERRQ(ierr);
937   ierr = TSSetPreStep(ts, RemoveDiscretePressureNullspace);CHKERRQ(ierr);
938   ierr = TSSetFromOptions(ts);CHKERRQ(ierr);
939 
940   ierr = TSSetComputeInitialCondition(ts, SetInitialConditions);CHKERRQ(ierr); /* Must come after SetFromOptions() */
941   ierr = SetInitialConditions(ts, u);CHKERRQ(ierr);
942   ierr = TSGetTime(ts, &t);CHKERRQ(ierr);
943   ierr = DMSetOutputSequenceNumber(dm, 0, t);CHKERRQ(ierr);
944   ierr = DMTSCheckFromOptions(ts, u);CHKERRQ(ierr);
945   ierr = TSMonitorSet(ts, MonitorError, &user, NULL);CHKERRQ(ierr);CHKERRQ(ierr);
946 
947   ierr = TSSolve(ts, u);CHKERRQ(ierr);
948   ierr = DMTSCheckFromOptions(ts, u);CHKERRQ(ierr);
949 
950   ierr = VecDestroy(&u);CHKERRQ(ierr);
951   ierr = DMDestroy(&user.dmCell);CHKERRQ(ierr);
952   ierr = DMDestroy(&dm);CHKERRQ(ierr);
953   ierr = TSDestroy(&ts);CHKERRQ(ierr);
954   ierr = PetscBagDestroy(&user.bag);CHKERRQ(ierr);
955   ierr = PetscFinalize();
956   return ierr;
957 }
958 
959 /*TEST
960 
961   test:
962     suffix: 2d_tri_p2_p1_p1
963     requires: triangle !single
964     args: -dm_plex_separate_marker -sol_type quadratic -dm_refine 0 \
965       -vel_petscspace_degree 2 -pres_petscspace_degree 1 -temp_petscspace_degree 1 \
966       -div_petscdualspace_lagrange_use_moments -div_petscdualspace_lagrange_moment_order 3 \
967       -dmts_check .001 -ts_max_steps 4 -ts_dt 0.1 \
968       -ksp_type fgmres -ksp_gmres_restart 10 -ksp_rtol 1.0e-9 -ksp_error_if_not_converged \
969       -pc_type fieldsplit -pc_fieldsplit_0_fields 0,2 -pc_fieldsplit_1_fields 1 -pc_fieldsplit_type schur -pc_fieldsplit_schur_factorization_type full \
970         -fieldsplit_0_pc_type lu \
971         -fieldsplit_pressure_ksp_rtol 1e-10 -fieldsplit_pressure_pc_type jacobi
972 
973   # TODO Need trig t for convergence in time, also need to refine in space
974   test:
975     # Using -dm_refine 5 -convest_num_refine 2 gives L_2 convergence rate: [0.89, 0.011, 1.0]
976     suffix: 2d_tri_p2_p1_p1_tconv
977     requires: triangle !single
978     args: -dm_plex_separate_marker -sol_type cubic_trig -dm_refine 0 \
979       -vel_petscspace_degree 2 -pres_petscspace_degree 1 -temp_petscspace_degree 1 \
980       -div_petscdualspace_lagrange_use_moments -div_petscdualspace_lagrange_moment_order 3 \
981       -ts_max_steps 4 -ts_dt 0.1 -ts_convergence_estimate -convest_num_refine 1 \
982       -snes_error_if_not_converged -snes_convergence_test correct_pressure \
983       -ksp_type fgmres -ksp_gmres_restart 10 -ksp_rtol 1.0e-9 -ksp_error_if_not_converged \
984       -pc_type fieldsplit -pc_fieldsplit_0_fields 0,2 -pc_fieldsplit_1_fields 1 -pc_fieldsplit_type schur -pc_fieldsplit_schur_factorization_type full \
985         -fieldsplit_0_pc_type lu \
986         -fieldsplit_pressure_ksp_rtol 1e-10 -fieldsplit_pressure_pc_type jacobi
987 
988   test:
989     # Using -dm_refine 3 -convest_num_refine 3 gives L_2 convergence rate: [3.0, 2.5, 1.9]
990     suffix: 2d_tri_p2_p1_p1_sconv
991     requires: triangle !single
992     args: -dm_plex_separate_marker -sol_type cubic -dm_refine 0 \
993       -vel_petscspace_degree 2 -pres_petscspace_degree 1 -temp_petscspace_degree 1 \
994       -div_petscdualspace_lagrange_use_moments -div_petscdualspace_lagrange_moment_order 3 \
995       -ts_max_steps 1 -ts_dt 1e-4 -ts_convergence_estimate -ts_convergence_temporal 0 -convest_num_refine 1 \
996       -snes_error_if_not_converged -snes_convergence_test correct_pressure \
997       -ksp_type fgmres -ksp_gmres_restart 10 -ksp_rtol 1.0e-9 -ksp_atol 1e-16 -ksp_error_if_not_converged \
998       -pc_type fieldsplit -pc_fieldsplit_0_fields 0,2 -pc_fieldsplit_1_fields 1 -pc_fieldsplit_type schur -pc_fieldsplit_schur_factorization_type full \
999         -fieldsplit_0_pc_type lu \
1000         -fieldsplit_pressure_ksp_rtol 1e-10 -fieldsplit_pressure_pc_type jacobi
1001 
1002   test:
1003     suffix: 2d_tri_p3_p2_p2
1004     requires: triangle !single
1005     args: -dm_plex_separate_marker -sol_type cubic -dm_refine 0 \
1006       -vel_petscspace_degree 3 -pres_petscspace_degree 2 -temp_petscspace_degree 2 \
1007       -div_petscdualspace_lagrange_use_moments -div_petscdualspace_lagrange_moment_order 3 \
1008       -dmts_check .001 -ts_max_steps 4 -ts_dt 0.1 \
1009       -snes_convergence_test correct_pressure \
1010       -ksp_type fgmres -ksp_gmres_restart 10 -ksp_rtol 1.0e-9 -ksp_error_if_not_converged \
1011       -pc_type fieldsplit -pc_fieldsplit_0_fields 0,2 -pc_fieldsplit_1_fields 1 -pc_fieldsplit_type schur -pc_fieldsplit_schur_factorization_type full \
1012         -fieldsplit_0_pc_type lu \
1013         -fieldsplit_pressure_ksp_rtol 1e-10 -fieldsplit_pressure_pc_type jacobi
1014 
1015   test:
1016     # Using -dm_refine 3 -convest_num_refine 3 gives L_2 convergence rate: [3.0, 2.1, 3.1]
1017     suffix: 2d_tri_p2_p1_p1_tg_sconv
1018     requires: triangle !single
1019     args: -dm_plex_separate_marker -sol_type taylor_green -dm_refine 0 \
1020       -vel_petscspace_degree 2 -pres_petscspace_degree 1 -temp_petscspace_degree 1 \
1021       -div_petscdualspace_lagrange_use_moments -div_petscdualspace_lagrange_moment_order 3 \
1022       -ts_max_steps 1 -ts_dt 1e-8 -ts_convergence_estimate -ts_convergence_temporal 0 -convest_num_refine 1 \
1023       -snes_error_if_not_converged -snes_convergence_test correct_pressure \
1024       -ksp_type fgmres -ksp_gmres_restart 10 -ksp_rtol 1.0e-9 -ksp_atol 1e-16 -ksp_error_if_not_converged \
1025       -pc_type fieldsplit -pc_fieldsplit_0_fields 0,2 -pc_fieldsplit_1_fields 1 -pc_fieldsplit_type schur -pc_fieldsplit_schur_factorization_type full \
1026         -fieldsplit_0_pc_type lu \
1027         -fieldsplit_pressure_ksp_rtol 1e-10 -fieldsplit_pressure_pc_type jacobi
1028 
1029   test:
1030     # Using -dm_refine 3 -convest_num_refine 2 gives L_2 convergence rate: [1.2, 1.5, 1.2]
1031     suffix: 2d_tri_p2_p1_p1_tg_tconv
1032     requires: triangle !single
1033     args: -dm_plex_separate_marker -sol_type taylor_green -dm_refine 0 \
1034       -vel_petscspace_degree 2 -pres_petscspace_degree 1 -temp_petscspace_degree 1 \
1035       -div_petscdualspace_lagrange_use_moments -div_petscdualspace_lagrange_moment_order 3 \
1036       -ts_max_steps 4 -ts_dt 0.1 -ts_convergence_estimate -convest_num_refine 1 \
1037       -snes_error_if_not_converged -snes_convergence_test correct_pressure \
1038       -ksp_type fgmres -ksp_gmres_restart 10 -ksp_rtol 1.0e-9 -ksp_atol 1e-16 -ksp_error_if_not_converged \
1039       -pc_type fieldsplit -pc_fieldsplit_0_fields 0,2 -pc_fieldsplit_1_fields 1 -pc_fieldsplit_type schur -pc_fieldsplit_schur_factorization_type full \
1040         -fieldsplit_0_pc_type lu \
1041         -fieldsplit_pressure_ksp_rtol 1e-10 -fieldsplit_pressure_pc_type jacobi
1042 
1043 TEST*/
1044