xref: /petsc/src/ts/tutorials/power_grid/ex6.c (revision 030f984af8d8bb4c203755d35bded3c05b3d83ce)
1 static char help[] = "Time-dependent PDE in 2d for calculating joint PDF. \n";
2 /*
3    p_t = -x_t*p_x -y_t*p_y + f(t)*p_yy
4    xmin < x < xmax, ymin < y < ymax;
5    x_t = (y - ws)  y_t = (ws/2H)*(Pm - Pmax*sin(x))
6 
7    Boundary conditions: -bc_type 0 => Zero dirichlet boundary
8                         -bc_type 1 => Steady state boundary condition
9    Steady state boundary condition found by setting p_t = 0
10 */
11 
12 #include <petscdm.h>
13 #include <petscdmda.h>
14 #include <petscts.h>
15 
16 /*
17    User-defined data structures and routines
18 */
19 typedef struct {
20   PetscScalar ws;   /* Synchronous speed */
21   PetscScalar H;    /* Inertia constant */
22   PetscScalar D;    /* Damping constant */
23   PetscScalar Pmax; /* Maximum power output of generator */
24   PetscScalar PM_min; /* Mean mechanical power input */
25   PetscScalar lambda; /* correlation time */
26   PetscScalar q;      /* noise strength */
27   PetscScalar mux;    /* Initial average angle */
28   PetscScalar sigmax; /* Standard deviation of initial angle */
29   PetscScalar muy;    /* Average speed */
30   PetscScalar sigmay; /* standard deviation of initial speed */
31   PetscScalar rho;    /* Cross-correlation coefficient */
32   PetscScalar t0;     /* Initial time */
33   PetscScalar tmax;   /* Final time */
34   PetscScalar xmin;   /* left boundary of angle */
35   PetscScalar xmax;   /* right boundary of angle */
36   PetscScalar ymin;   /* bottom boundary of speed */
37   PetscScalar ymax;   /* top boundary of speed */
38   PetscScalar dx;     /* x step size */
39   PetscScalar dy;     /* y step size */
40   PetscInt    bc; /* Boundary conditions */
41   PetscScalar disper_coe; /* Dispersion coefficient */
42   DM          da;
43 } AppCtx;
44 
45 PetscErrorCode Parameter_settings(AppCtx*);
46 PetscErrorCode ini_bou(Vec,AppCtx*);
47 PetscErrorCode IFunction(TS,PetscReal,Vec,Vec,Vec,void*);
48 PetscErrorCode IJacobian(TS,PetscReal,Vec,Vec,PetscReal,Mat,Mat,void*);
49 PetscErrorCode PostStep(TS);
50 
51 int main(int argc, char **argv)
52 {
53   PetscErrorCode ierr;
54   Vec            x;  /* Solution vector */
55   TS             ts;   /* Time-stepping context */
56   AppCtx         user; /* Application context */
57   Mat            J;
58   PetscViewer    viewer;
59 
60   ierr = PetscInitialize(&argc,&argv,"petscopt_ex6", help);if (ierr) return ierr;
61   /* Get physics and time parameters */
62   ierr = Parameter_settings(&user);CHKERRQ(ierr);
63   /* Create a 2D DA with dof = 1 */
64   ierr = DMDACreate2d(PETSC_COMM_WORLD,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DMDA_STENCIL_STAR,4,4,PETSC_DECIDE,PETSC_DECIDE,1,1,NULL,NULL,&user.da);CHKERRQ(ierr);
65   ierr = DMSetFromOptions(user.da);CHKERRQ(ierr);
66   ierr = DMSetUp(user.da);CHKERRQ(ierr);
67   /* Set x and y coordinates */
68   ierr = DMDASetUniformCoordinates(user.da,user.xmin,user.xmax,user.ymin,user.ymax,0.0,1.0);CHKERRQ(ierr);
69 
70   /* Get global vector x from DM  */
71   ierr = DMCreateGlobalVector(user.da,&x);CHKERRQ(ierr);
72 
73   ierr = ini_bou(x,&user);CHKERRQ(ierr);
74   ierr = PetscViewerBinaryOpen(PETSC_COMM_WORLD,"ini_x",FILE_MODE_WRITE,&viewer);CHKERRQ(ierr);
75   ierr = VecView(x,viewer);CHKERRQ(ierr);
76   ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
77 
78   /* Get Jacobian matrix structure from the da */
79   ierr = DMSetMatType(user.da,MATAIJ);CHKERRQ(ierr);
80   ierr = DMCreateMatrix(user.da,&J);CHKERRQ(ierr);
81 
82   ierr = TSCreate(PETSC_COMM_WORLD,&ts);CHKERRQ(ierr);
83   ierr = TSSetProblemType(ts,TS_NONLINEAR);CHKERRQ(ierr);
84   ierr = TSSetIFunction(ts,NULL,IFunction,&user);CHKERRQ(ierr);
85   ierr = TSSetIJacobian(ts,J,J,IJacobian,&user);CHKERRQ(ierr);
86   ierr = TSSetApplicationContext(ts,&user);CHKERRQ(ierr);
87   ierr = TSSetMaxTime(ts,user.tmax);CHKERRQ(ierr);
88   ierr = TSSetExactFinalTime(ts,TS_EXACTFINALTIME_MATCHSTEP);CHKERRQ(ierr);
89   ierr = TSSetTime(ts,user.t0);CHKERRQ(ierr);
90   ierr = TSSetTimeStep(ts,.005);CHKERRQ(ierr);
91   ierr = TSSetFromOptions(ts);CHKERRQ(ierr);
92   ierr = TSSetPostStep(ts,PostStep);CHKERRQ(ierr);
93   ierr = TSSolve(ts,x);CHKERRQ(ierr);
94 
95   ierr = PetscViewerBinaryOpen(PETSC_COMM_WORLD,"fin_x",FILE_MODE_WRITE,&viewer);CHKERRQ(ierr);
96   ierr = VecView(x,viewer);CHKERRQ(ierr);
97   ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
98 
99   ierr = VecDestroy(&x);CHKERRQ(ierr);
100   ierr = MatDestroy(&J);CHKERRQ(ierr);
101   ierr = DMDestroy(&user.da);CHKERRQ(ierr);
102   ierr = TSDestroy(&ts);CHKERRQ(ierr);
103   ierr = PetscFinalize();
104   return ierr;
105 }
106 
107 PetscErrorCode PostStep(TS ts)
108 {
109   PetscErrorCode ierr;
110   Vec            X;
111   AppCtx         *user;
112   PetscScalar    sum;
113   PetscReal      t;
114 
115   PetscFunctionBegin;
116   ierr = TSGetApplicationContext(ts,&user);CHKERRQ(ierr);
117   ierr = TSGetTime(ts,&t);CHKERRQ(ierr);
118   ierr = TSGetSolution(ts,&X);CHKERRQ(ierr);
119   ierr = VecSum(X,&sum);CHKERRQ(ierr);
120   ierr = PetscPrintf(PETSC_COMM_WORLD,"sum(p)*dw*dtheta at t = %3.2f = %3.6f\n",(double)t,(double)sum*user->dx*user->dy);CHKERRQ(ierr);
121   PetscFunctionReturn(0);
122 }
123 
124 PetscErrorCode ini_bou(Vec X,AppCtx* user)
125 {
126   PetscErrorCode ierr;
127   DM             cda;
128   DMDACoor2d     **coors;
129   PetscScalar    **p;
130   Vec            gc;
131   PetscInt       i,j;
132   PetscInt       xs,ys,xm,ym,M,N;
133   PetscScalar    xi,yi;
134   PetscScalar    sigmax=user->sigmax,sigmay=user->sigmay;
135   PetscScalar    rho   =user->rho;
136   PetscScalar    mux   =user->mux,muy=user->muy;
137   PetscMPIInt    rank;
138 
139   PetscFunctionBeginUser;
140   ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRMPI(ierr);
141   ierr = DMDAGetInfo(user->da,NULL,&M,&N,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL);CHKERRQ(ierr);
142   user->dx = (user->xmax - user->xmin)/(M-1); user->dy = (user->ymax - user->ymin)/(N-1);
143   ierr = DMGetCoordinateDM(user->da,&cda);CHKERRQ(ierr);
144   ierr = DMGetCoordinates(user->da,&gc);CHKERRQ(ierr);
145   ierr = DMDAVecGetArray(cda,gc,&coors);CHKERRQ(ierr);
146   ierr = DMDAVecGetArray(user->da,X,&p);CHKERRQ(ierr);
147   ierr = DMDAGetCorners(cda,&xs,&ys,0,&xm,&ym,0);CHKERRQ(ierr);
148   for (i=xs; i < xs+xm; i++) {
149     for (j=ys; j < ys+ym; j++) {
150       xi = coors[j][i].x; yi = coors[j][i].y;
151       if (i == 0 || j == 0 || i == M-1 || j == N-1) p[j][i] = 0.0;
152       else p[j][i] = (0.5/(PETSC_PI*sigmax*sigmay*PetscSqrtScalar(1.0-rho*rho)))*PetscExpScalar(-0.5/(1-rho*rho)*(PetscPowScalar((xi-mux)/sigmax,2) + PetscPowScalar((yi-muy)/sigmay,2) - 2*rho*(xi-mux)*(yi-muy)/(sigmax*sigmay)));
153     }
154   }
155   /*  p[N/2+N%2][M/2+M%2] = 1/(user->dx*user->dy); */
156 
157   ierr = DMDAVecRestoreArray(cda,gc,&coors);CHKERRQ(ierr);
158   ierr = DMDAVecRestoreArray(user->da,X,&p);CHKERRQ(ierr);
159   PetscFunctionReturn(0);
160 }
161 
162 /* First advection term */
163 PetscErrorCode adv1(PetscScalar **p,PetscScalar y,PetscInt i,PetscInt j,PetscInt M,PetscScalar *p1,AppCtx *user)
164 {
165   PetscScalar f;
166   /*  PetscScalar v1,v2,v3,v4,v5,s1,s2,s3; */
167   PetscFunctionBegin;
168   /*  if (i > 2 && i < M-2) {
169     v1 = (y-user->ws)*(p[j][i-2] - p[j][i-3])/user->dx;
170     v2 = (y-user->ws)*(p[j][i-1] - p[j][i-2])/user->dx;
171     v3 = (y-user->ws)*(p[j][i] - p[j][i-1])/user->dx;
172     v4 = (y-user->ws)*(p[j][i+1] - p[j][i])/user->dx;
173     v5 = (y-user->ws)*(p[j][i+1] - p[j][i+2])/user->dx;
174 
175     s1 = v1/3.0 - (7.0/6.0)*v2 + (11.0/6.0)*v3;
176     s2 =-v2/6.0 + (5.0/6.0)*v3 + (1.0/3.0)*v4;
177     s3 = v3/3.0 + (5.0/6.0)*v4 - (1.0/6.0)*v5;
178 
179     *p1 = 0.1*s1 + 0.6*s2 + 0.3*s3;
180     } else *p1 = 0.0; */
181   f   =  (y - user->ws);
182   *p1 = f*(p[j][i+1] - p[j][i-1])/(2*user->dx);
183   PetscFunctionReturn(0);
184 }
185 
186 /* Second advection term */
187 PetscErrorCode adv2(PetscScalar **p,PetscScalar x,PetscInt i,PetscInt j,PetscInt N,PetscScalar *p2,AppCtx *user)
188 {
189   PetscScalar f;
190   /*  PetscScalar v1,v2,v3,v4,v5,s1,s2,s3; */
191   PetscFunctionBegin;
192   /*  if (j > 2 && j < N-2) {
193     v1 = (user->ws/(2*user->H))*(user->PM_min - user->Pmax*sin(x))*(p[j-2][i] - p[j-3][i])/user->dy;
194     v2 = (user->ws/(2*user->H))*(user->PM_min - user->Pmax*sin(x))*(p[j-1][i] - p[j-2][i])/user->dy;
195     v3 = (user->ws/(2*user->H))*(user->PM_min - user->Pmax*sin(x))*(p[j][i] - p[j-1][i])/user->dy;
196     v4 = (user->ws/(2*user->H))*(user->PM_min - user->Pmax*sin(x))*(p[j+1][i] - p[j][i])/user->dy;
197     v5 = (user->ws/(2*user->H))*(user->PM_min - user->Pmax*sin(x))*(p[j+2][i] - p[j+1][i])/user->dy;
198 
199     s1 = v1/3.0 - (7.0/6.0)*v2 + (11.0/6.0)*v3;
200     s2 =-v2/6.0 + (5.0/6.0)*v3 + (1.0/3.0)*v4;
201     s3 = v3/3.0 + (5.0/6.0)*v4 - (1.0/6.0)*v5;
202 
203     *p2 = 0.1*s1 + 0.6*s2 + 0.3*s3;
204     } else *p2 = 0.0; */
205   f   = (user->ws/(2*user->H))*(user->PM_min - user->Pmax*PetscSinScalar(x));
206   *p2 = f*(p[j+1][i] - p[j-1][i])/(2*user->dy);
207   PetscFunctionReturn(0);
208 }
209 
210 /* Diffusion term */
211 PetscErrorCode diffuse(PetscScalar **p,PetscInt i,PetscInt j,PetscReal t,PetscScalar *p_diff,AppCtx * user)
212 {
213   PetscFunctionBeginUser;
214 
215   *p_diff = user->disper_coe*((p[j-1][i] - 2*p[j][i] + p[j+1][i])/(user->dy*user->dy));
216   PetscFunctionReturn(0);
217 }
218 
219 PetscErrorCode BoundaryConditions(PetscScalar **p,DMDACoor2d **coors,PetscInt i,PetscInt j,PetscInt M, PetscInt N,PetscScalar **f,AppCtx *user)
220 {
221   PetscScalar fwc,fthetac;
222   PetscScalar w=coors[j][i].y,theta=coors[j][i].x;
223 
224   PetscFunctionBeginUser;
225   if (user->bc == 0) { /* Natural boundary condition */
226     f[j][i] = p[j][i];
227   } else { /* Steady state boundary condition */
228     fthetac = user->ws/(2*user->H)*(user->PM_min - user->Pmax*PetscSinScalar(theta));
229     fwc = (w*w/2.0 - user->ws*w);
230     if (i == 0 && j == 0) { /* left bottom corner */
231       f[j][i] = fwc*(p[j][i+1] - p[j][i])/user->dx + fthetac*p[j][i] - user->disper_coe*(p[j+1][i] - p[j][i])/user->dy;
232     } else if (i == 0 && j == N-1) { /* right bottom corner */
233       f[j][i] = fwc*(p[j][i+1] - p[j][i])/user->dx + fthetac*p[j][i] - user->disper_coe*(p[j][i] - p[j-1][i])/user->dy;
234     } else if (i == M-1 && j == 0) { /* left top corner */
235       f[j][i] = fwc*(p[j][i] - p[j][i-1])/user->dx + fthetac*p[j][i] - user->disper_coe*(p[j+1][i] - p[j][i])/user->dy;
236     } else if (i == M-1 && j == N-1) { /* right top corner */
237       f[j][i] = fwc*(p[j][i] - p[j][i-1])/user->dx + fthetac*p[j][i] - user->disper_coe*(p[j][i] - p[j-1][i])/user->dy;
238     } else if (i == 0) { /* Bottom edge */
239       f[j][i] = fwc*(p[j][i+1] - p[j][i])/(user->dx) + fthetac*p[j][i] - user->disper_coe*(p[j+1][i] - p[j-1][i])/(2*user->dy);
240     } else if (i == M-1) { /* Top edge */
241       f[j][i] = fwc*(p[j][i] - p[j][i-1])/(user->dx) + fthetac*p[j][i] - user->disper_coe*(p[j+1][i] - p[j-1][i])/(2*user->dy);
242     } else if (j == 0) { /* Left edge */
243       f[j][i] = fwc*(p[j][i+1] - p[j][i-1])/(2*user->dx) + fthetac*p[j][i] - user->disper_coe*(p[j+1][i] - p[j][i])/(user->dy);
244     } else if (j == N-1) { /* Right edge */
245       f[j][i] = fwc*(p[j][i+1] - p[j][i-1])/(2*user->dx) + fthetac*p[j][i] - user->disper_coe*(p[j][i] - p[j-1][i])/(user->dy);
246     }
247   }
248   PetscFunctionReturn(0);
249 }
250 
251 PetscErrorCode IFunction(TS ts,PetscReal t,Vec X,Vec Xdot,Vec F,void *ctx)
252 {
253   PetscErrorCode ierr;
254   AppCtx         *user=(AppCtx*)ctx;
255   DM             cda;
256   DMDACoor2d     **coors;
257   PetscScalar    **p,**f,**pdot;
258   PetscInt       i,j;
259   PetscInt       xs,ys,xm,ym,M,N;
260   Vec            localX,gc,localXdot;
261   PetscScalar    p_adv1,p_adv2,p_diff;
262 
263   PetscFunctionBeginUser;
264   ierr = DMDAGetInfo(user->da,NULL,&M,&N,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL);CHKERRQ(ierr);
265   ierr = DMGetCoordinateDM(user->da,&cda);CHKERRQ(ierr);
266   ierr = DMDAGetCorners(cda,&xs,&ys,0,&xm,&ym,0);CHKERRQ(ierr);
267 
268   ierr = DMGetLocalVector(user->da,&localX);CHKERRQ(ierr);
269   ierr = DMGetLocalVector(user->da,&localXdot);CHKERRQ(ierr);
270 
271   ierr = DMGlobalToLocalBegin(user->da,X,INSERT_VALUES,localX);CHKERRQ(ierr);
272   ierr = DMGlobalToLocalEnd(user->da,X,INSERT_VALUES,localX);CHKERRQ(ierr);
273   ierr = DMGlobalToLocalBegin(user->da,Xdot,INSERT_VALUES,localXdot);CHKERRQ(ierr);
274   ierr = DMGlobalToLocalEnd(user->da,Xdot,INSERT_VALUES,localXdot);CHKERRQ(ierr);
275 
276   ierr = DMGetCoordinatesLocal(user->da,&gc);CHKERRQ(ierr);
277 
278   ierr = DMDAVecGetArrayRead(cda,gc,&coors);CHKERRQ(ierr);
279   ierr = DMDAVecGetArrayRead(user->da,localX,&p);CHKERRQ(ierr);
280   ierr = DMDAVecGetArrayRead(user->da,localXdot,&pdot);CHKERRQ(ierr);
281   ierr = DMDAVecGetArray(user->da,F,&f);CHKERRQ(ierr);
282 
283   user->disper_coe = PetscPowScalar((user->lambda*user->ws)/(2*user->H),2)*user->q*(1.0-PetscExpScalar(-t/user->lambda));
284   for (i=xs; i < xs+xm; i++) {
285     for (j=ys; j < ys+ym; j++) {
286       if (i == 0 || j == 0 || i == M-1 || j == N-1) {
287         ierr = BoundaryConditions(p,coors,i,j,M,N,f,user);CHKERRQ(ierr);
288       } else {
289         ierr = adv1(p,coors[j][i].y,i,j,M,&p_adv1,user);CHKERRQ(ierr);
290         ierr = adv2(p,coors[j][i].x,i,j,N,&p_adv2,user);CHKERRQ(ierr);
291         ierr = diffuse(p,i,j,t,&p_diff,user);CHKERRQ(ierr);
292         f[j][i] = -p_adv1 - p_adv2 + p_diff - pdot[j][i];
293       }
294     }
295   }
296   ierr = DMDAVecRestoreArrayRead(user->da,localX,&p);CHKERRQ(ierr);
297   ierr = DMDAVecRestoreArrayRead(user->da,localX,&pdot);CHKERRQ(ierr);
298   ierr = DMRestoreLocalVector(user->da,&localX);CHKERRQ(ierr);
299   ierr = DMRestoreLocalVector(user->da,&localXdot);CHKERRQ(ierr);
300   ierr = DMDAVecRestoreArray(user->da,F,&f);CHKERRQ(ierr);
301   ierr = DMDAVecRestoreArrayRead(cda,gc,&coors);CHKERRQ(ierr);
302 
303   PetscFunctionReturn(0);
304 }
305 
306 PetscErrorCode IJacobian(TS ts,PetscReal t,Vec X,Vec Xdot,PetscReal a,Mat J,Mat Jpre,void *ctx)
307 {
308   PetscErrorCode ierr;
309   AppCtx         *user=(AppCtx*)ctx;
310   DM             cda;
311   DMDACoor2d     **coors;
312   PetscInt       i,j;
313   PetscInt       xs,ys,xm,ym,M,N;
314   Vec            gc;
315   PetscScalar    val[5],xi,yi;
316   MatStencil     row,col[5];
317   PetscScalar    c1,c3,c5;
318 
319   PetscFunctionBeginUser;
320   ierr = DMDAGetInfo(user->da,NULL,&M,&N,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL);CHKERRQ(ierr);
321   ierr = DMGetCoordinateDM(user->da,&cda);CHKERRQ(ierr);
322   ierr = DMDAGetCorners(cda,&xs,&ys,0,&xm,&ym,0);CHKERRQ(ierr);
323 
324   ierr = DMGetCoordinatesLocal(user->da,&gc);CHKERRQ(ierr);
325   ierr = DMDAVecGetArrayRead(cda,gc,&coors);CHKERRQ(ierr);
326   for (i=xs; i < xs+xm; i++) {
327     for (j=ys; j < ys+ym; j++) {
328       PetscInt nc = 0;
329       xi = coors[j][i].x; yi = coors[j][i].y;
330       row.i = i; row.j = j;
331       if (i == 0 || j == 0 || i == M-1 || j == N-1) {
332         if (user->bc == 0) {
333           col[nc].i = i; col[nc].j = j; val[nc++] = 1.0;
334         } else {
335           PetscScalar fthetac,fwc;
336           fthetac = user->ws/(2*user->H)*(user->PM_min - user->Pmax*PetscSinScalar(xi));
337           fwc     = (yi*yi/2.0 - user->ws*yi);
338           if (i==0 && j==0) {
339             col[nc].i = i+1; col[nc].j = j;   val[nc++] = fwc/user->dx;
340             col[nc].i = i;   col[nc].j = j+1; val[nc++] = -user->disper_coe/user->dy;
341             col[nc].i = i;   col[nc].j = j;   val[nc++] = -fwc/user->dx + fthetac + user->disper_coe/user->dy;
342           } else if (i==0 && j == N-1) {
343             col[nc].i = i+1; col[nc].j = j;   val[nc++] = fwc/user->dx;
344             col[nc].i = i;   col[nc].j = j-1; val[nc++] = user->disper_coe/user->dy;
345             col[nc].i = i;   col[nc].j = j;   val[nc++] = -fwc/user->dx + fthetac - user->disper_coe/user->dy;
346           } else if (i== M-1 && j == 0) {
347             col[nc].i = i-1; col[nc].j = j;   val[nc++] = -fwc/user->dx;
348             col[nc].i = i;   col[nc].j = j+1; val[nc++] = -user->disper_coe/user->dy;
349             col[nc].i = i;   col[nc].j = j;   val[nc++] =  fwc/user->dx + fthetac + user->disper_coe/user->dy;
350           } else if (i == M-1 && j == N-1) {
351             col[nc].i = i-1; col[nc].j = j;   val[nc++] = -fwc/user->dx;
352             col[nc].i = i;   col[nc].j = j-1; val[nc++] =  user->disper_coe/user->dy;
353             col[nc].i = i;   col[nc].j = j;   val[nc++] =  fwc/user->dx + fthetac - user->disper_coe/user->dy;
354           } else if (i==0) {
355             col[nc].i = i+1; col[nc].j = j;   val[nc++] = fwc/user->dx;
356             col[nc].i = i;   col[nc].j = j+1; val[nc++] = -user->disper_coe/(2*user->dy);
357             col[nc].i = i;   col[nc].j = j-1; val[nc++] =  user->disper_coe/(2*user->dy);
358             col[nc].i = i;   col[nc].j = j;   val[nc++] = -fwc/user->dx + fthetac;
359           } else if (i == M-1) {
360             col[nc].i = i-1; col[nc].j = j;   val[nc++] = -fwc/user->dx;
361             col[nc].i = i;   col[nc].j = j+1; val[nc++] = -user->disper_coe/(2*user->dy);
362             col[nc].i = i;   col[nc].j = j-1; val[nc++] =  user->disper_coe/(2*user->dy);
363             col[nc].i = i;   col[nc].j = j;   val[nc++] = fwc/user->dx + fthetac;
364           } else if (j==0) {
365             col[nc].i = i+1; col[nc].j = j;   val[nc++] = fwc/(2*user->dx);
366             col[nc].i = i-1; col[nc].j = j;   val[nc++] = -fwc/(2*user->dx);
367             col[nc].i = i;   col[nc].j = j+1; val[nc++] = -user->disper_coe/user->dy;
368             col[nc].i = i;   col[nc].j = j;   val[nc++] = user->disper_coe/user->dy + fthetac;
369           } else if (j == N-1) {
370             col[nc].i = i+1; col[nc].j = j;   val[nc++] = fwc/(2*user->dx);
371             col[nc].i = i-1; col[nc].j = j;   val[nc++] = -fwc/(2*user->dx);
372             col[nc].i = i;   col[nc].j = j-1; val[nc++] = user->disper_coe/user->dy;
373             col[nc].i = i;   col[nc].j = j;   val[nc++] = -user->disper_coe/user->dy + fthetac;
374           }
375         }
376       } else {
377         c1        = (yi-user->ws)/(2*user->dx);
378         c3        = (user->ws/(2.0*user->H))*(user->PM_min - user->Pmax*PetscSinScalar(xi))/(2*user->dy);
379         c5        = (PetscPowScalar((user->lambda*user->ws)/(2*user->H),2)*user->q*(1.0-PetscExpScalar(-t/user->lambda)))/(user->dy*user->dy);
380         col[nc].i = i-1; col[nc].j = j;   val[nc++] = c1;
381         col[nc].i = i+1; col[nc].j = j;   val[nc++] = -c1;
382         col[nc].i = i;   col[nc].j = j-1; val[nc++] = c3 + c5;
383         col[nc].i = i;   col[nc].j = j+1; val[nc++] = -c3 + c5;
384         col[nc].i = i;   col[nc].j = j;   val[nc++] = -2*c5 -a;
385       }
386       ierr = MatSetValuesStencil(Jpre,1,&row,nc,col,val,INSERT_VALUES);CHKERRQ(ierr);
387     }
388   }
389   ierr = DMDAVecRestoreArrayRead(cda,gc,&coors);CHKERRQ(ierr);
390 
391   ierr =  MatAssemblyBegin(Jpre,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
392   ierr = MatAssemblyEnd(Jpre,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
393   if (J != Jpre) {
394     ierr = MatAssemblyBegin(J,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
395     ierr = MatAssemblyEnd(J,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
396   }
397   PetscFunctionReturn(0);
398 }
399 
400 PetscErrorCode Parameter_settings(AppCtx *user)
401 {
402   PetscErrorCode ierr;
403   PetscBool      flg;
404 
405   PetscFunctionBeginUser;
406 
407   /* Set default parameters */
408   user->ws     = 1.0;
409   user->H      = 5.0;  user->Pmax   = 2.1;
410   user->PM_min = 1.0;  user->lambda = 0.1;
411   user->q      = 1.0;  user->mux    = PetscAsinScalar(user->PM_min/user->Pmax);
412   user->sigmax = 0.1;
413   user->sigmay = 0.1;  user->rho  = 0.0;
414   user->t0     = 0.0;  user->tmax = 2.0;
415   user->xmin   = -1.0; user->xmax = 10.0;
416   user->ymin   = -1.0; user->ymax = 10.0;
417   user->bc     = 0;
418 
419   ierr = PetscOptionsGetScalar(NULL,NULL,"-ws",&user->ws,&flg);CHKERRQ(ierr);
420   ierr = PetscOptionsGetScalar(NULL,NULL,"-Inertia",&user->H,&flg);CHKERRQ(ierr);
421   ierr = PetscOptionsGetScalar(NULL,NULL,"-Pmax",&user->Pmax,&flg);CHKERRQ(ierr);
422   ierr = PetscOptionsGetScalar(NULL,NULL,"-PM_min",&user->PM_min,&flg);CHKERRQ(ierr);
423   ierr = PetscOptionsGetScalar(NULL,NULL,"-lambda",&user->lambda,&flg);CHKERRQ(ierr);
424   ierr = PetscOptionsGetScalar(NULL,NULL,"-q",&user->q,&flg);CHKERRQ(ierr);
425   ierr = PetscOptionsGetScalar(NULL,NULL,"-mux",&user->mux,&flg);CHKERRQ(ierr);
426   ierr = PetscOptionsGetScalar(NULL,NULL,"-sigmax",&user->sigmax,&flg);CHKERRQ(ierr);
427   ierr = PetscOptionsGetScalar(NULL,NULL,"-muy",&user->muy,&flg);CHKERRQ(ierr);
428   ierr = PetscOptionsGetScalar(NULL,NULL,"-sigmay",&user->sigmay,&flg);CHKERRQ(ierr);
429   ierr = PetscOptionsGetScalar(NULL,NULL,"-rho",&user->rho,&flg);CHKERRQ(ierr);
430   ierr = PetscOptionsGetScalar(NULL,NULL,"-t0",&user->t0,&flg);CHKERRQ(ierr);
431   ierr = PetscOptionsGetScalar(NULL,NULL,"-tmax",&user->tmax,&flg);CHKERRQ(ierr);
432   ierr = PetscOptionsGetScalar(NULL,NULL,"-xmin",&user->xmin,&flg);CHKERRQ(ierr);
433   ierr = PetscOptionsGetScalar(NULL,NULL,"-xmax",&user->xmax,&flg);CHKERRQ(ierr);
434   ierr = PetscOptionsGetScalar(NULL,NULL,"-ymin",&user->ymin,&flg);CHKERRQ(ierr);
435   ierr = PetscOptionsGetScalar(NULL,NULL,"-ymax",&user->ymax,&flg);CHKERRQ(ierr);
436   ierr = PetscOptionsGetInt(NULL,NULL,"-bc_type",&user->bc,&flg);CHKERRQ(ierr);
437   user->muy = user->ws;
438   PetscFunctionReturn(0);
439 }
440 
441 /*TEST
442 
443    build:
444       requires: !complex
445 
446    test:
447       args: -nox -ts_max_steps 2
448       localrunfiles: petscopt_ex6
449       timeoutfactor: 4
450 
451 TEST*/
452