xref: /petsc/src/snes/tests/ex241.cxx (revision c4762a1b19cd2af06abeed90e8f9d34fb975dd94)
1*c4762a1bSJed Brown static char help[] = "Artificial test to check that snes->domainerror is being reset appropriately";
2*c4762a1bSJed Brown 
3*c4762a1bSJed Brown /* ------------------------------------------------------------------------
4*c4762a1bSJed Brown 
5*c4762a1bSJed Brown     Artificial test to check that snes->domainerror is being reset appropriately
6*c4762a1bSJed Brown 
7*c4762a1bSJed Brown   ------------------------------------------------------------------------- */
8*c4762a1bSJed Brown 
9*c4762a1bSJed Brown #define PETSC_SKIP_COMPLEX
10*c4762a1bSJed Brown #include <petscsnes.h>
11*c4762a1bSJed Brown 
12*c4762a1bSJed Brown typedef struct {
13*c4762a1bSJed Brown   PetscReal value;              /* parameter in nonlinear function */
14*c4762a1bSJed Brown } AppCtx;
15*c4762a1bSJed Brown 
16*c4762a1bSJed Brown PetscErrorCode UserFunction(SNES,Vec,Vec,void*);
17*c4762a1bSJed Brown PetscErrorCode UserJacobian(SNES,Vec,Mat,Mat,void*);
18*c4762a1bSJed Brown 
19*c4762a1bSJed Brown int main(int argc,char **argv)
20*c4762a1bSJed Brown {
21*c4762a1bSJed Brown   SNES           snes;
22*c4762a1bSJed Brown   Vec            x,r;
23*c4762a1bSJed Brown   Mat            J;
24*c4762a1bSJed Brown   PetscErrorCode ierr;
25*c4762a1bSJed Brown   PetscInt       its;
26*c4762a1bSJed Brown   AppCtx         user;
27*c4762a1bSJed Brown   PetscMPIInt    size;
28*c4762a1bSJed Brown 
29*c4762a1bSJed Brown   ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
30*c4762a1bSJed Brown   ierr = MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRQ(ierr);
31*c4762a1bSJed Brown   if (size != 1) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_WRONG_MPI_SIZE,"This is a uniprocessor example only!");
32*c4762a1bSJed Brown 
33*c4762a1bSJed Brown   /* Allocate vectors / matrix */
34*c4762a1bSJed Brown   ierr = VecCreate(PETSC_COMM_WORLD,&x);CHKERRQ(ierr);
35*c4762a1bSJed Brown   ierr = VecSetSizes(x,PETSC_DECIDE,1);CHKERRQ(ierr);
36*c4762a1bSJed Brown   ierr = VecSetFromOptions(x);CHKERRQ(ierr);
37*c4762a1bSJed Brown   ierr = VecDuplicate(x,&r);CHKERRQ(ierr);
38*c4762a1bSJed Brown 
39*c4762a1bSJed Brown   ierr = MatCreateSeqAIJ(PETSC_COMM_WORLD,1,1,1,NULL,&J);CHKERRQ(ierr);
40*c4762a1bSJed Brown 
41*c4762a1bSJed Brown   /* Create / set-up SNES */
42*c4762a1bSJed Brown   ierr = SNESCreate(PETSC_COMM_WORLD,&snes);CHKERRQ(ierr);
43*c4762a1bSJed Brown   ierr = SNESSetFunction(snes,r,UserFunction,&user);CHKERRQ(ierr);
44*c4762a1bSJed Brown   ierr = SNESSetJacobian(snes,J,J,UserJacobian,&user);CHKERRQ(ierr);
45*c4762a1bSJed Brown   ierr = SNESSetFromOptions(snes);CHKERRQ(ierr);
46*c4762a1bSJed Brown 
47*c4762a1bSJed Brown   /* Set initial guess (=1) and target value */
48*c4762a1bSJed Brown   user.value = 1e-4;
49*c4762a1bSJed Brown 
50*c4762a1bSJed Brown   ierr = VecSet(x,1.0);CHKERRQ(ierr);
51*c4762a1bSJed Brown 
52*c4762a1bSJed Brown   /* Set initial guess / solve */
53*c4762a1bSJed Brown   ierr = SNESSolve(snes,NULL,x);CHKERRQ(ierr);
54*c4762a1bSJed Brown   ierr = SNESGetIterationNumber(snes,&its);CHKERRQ(ierr);
55*c4762a1bSJed Brown   ierr = PetscPrintf(PETSC_COMM_WORLD,"Number of SNES iterations = %D\n",its);CHKERRQ(ierr);
56*c4762a1bSJed Brown   ierr = VecView(x,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
57*c4762a1bSJed Brown 
58*c4762a1bSJed Brown   /* Done */
59*c4762a1bSJed Brown   ierr = VecDestroy(&x);CHKERRQ(ierr);
60*c4762a1bSJed Brown   ierr = VecDestroy(&r);CHKERRQ(ierr);
61*c4762a1bSJed Brown   ierr = MatDestroy(&J);CHKERRQ(ierr);
62*c4762a1bSJed Brown   ierr = SNESDestroy(&snes);CHKERRQ(ierr);
63*c4762a1bSJed Brown   ierr = PetscFinalize();
64*c4762a1bSJed Brown   return ierr;
65*c4762a1bSJed Brown }
66*c4762a1bSJed Brown 
67*c4762a1bSJed Brown /*
68*c4762a1bSJed Brown     UserFunction - for nonlinear function x^2 - value = 0
69*c4762a1bSJed Brown */
70*c4762a1bSJed Brown PetscErrorCode UserFunction(SNES snes,Vec X,Vec F,void *ptr)
71*c4762a1bSJed Brown {
72*c4762a1bSJed Brown   AppCtx            *user = (AppCtx*)ptr;
73*c4762a1bSJed Brown   PetscInt          N,i;
74*c4762a1bSJed Brown   PetscScalar       *f;
75*c4762a1bSJed Brown   PetscReal         half;
76*c4762a1bSJed Brown   const PetscScalar *x;
77*c4762a1bSJed Brown   PetscErrorCode    ierr;
78*c4762a1bSJed Brown 
79*c4762a1bSJed Brown   half = 0.5;
80*c4762a1bSJed Brown 
81*c4762a1bSJed Brown   ierr = VecGetSize(X,&N);CHKERRQ(ierr);
82*c4762a1bSJed Brown   ierr = VecGetArrayRead(X,&x);CHKERRQ(ierr);
83*c4762a1bSJed Brown   ierr = VecGetArray(F,&f);CHKERRQ(ierr);
84*c4762a1bSJed Brown 
85*c4762a1bSJed Brown   /* Calculate residual */
86*c4762a1bSJed Brown   for(i=0; i<N; ++i) {
87*c4762a1bSJed Brown     /*
88*c4762a1bSJed Brown        Test for domain error.
89*c4762a1bSJed Brown        Artifical test is applied.  With starting value 1.0, first iterate will be 0.5 + user->value/2.
90*c4762a1bSJed Brown        Declare (0.5-value,0.5+value) to be infeasible.
91*c4762a1bSJed Brown        In later iterations, snes->domainerror should be cleared, allowing iterations in the feasible region to be accepted.
92*c4762a1bSJed Brown     */
93*c4762a1bSJed Brown     if( (half-user->value) < PetscRealPart(x[i]) && PetscRealPart(x[i]) < (half+user->value) ) {
94*c4762a1bSJed Brown       ierr = PetscPrintf(PETSC_COMM_WORLD,"DOMAIN ERROR: x=%g\n",(double)PetscRealPart(x[i]));CHKERRQ(ierr);
95*c4762a1bSJed Brown       ierr = SNESSetFunctionDomainError(snes);CHKERRQ(ierr);
96*c4762a1bSJed Brown     }
97*c4762a1bSJed Brown     f[i] = x[i]*x[i] - user->value;
98*c4762a1bSJed Brown   }
99*c4762a1bSJed Brown   ierr = VecRestoreArrayRead(X,&x);CHKERRQ(ierr);
100*c4762a1bSJed Brown   ierr = VecRestoreArray(F,&f);CHKERRQ(ierr);
101*c4762a1bSJed Brown   return 0;
102*c4762a1bSJed Brown }
103*c4762a1bSJed Brown 
104*c4762a1bSJed Brown /*
105*c4762a1bSJed Brown     UserJacobian - for nonlinear function x^2 - value = 0
106*c4762a1bSJed Brown */
107*c4762a1bSJed Brown PetscErrorCode UserJacobian(SNES snes,Vec X,Mat J,Mat jac,void *ptr)
108*c4762a1bSJed Brown {
109*c4762a1bSJed Brown   PetscInt          N,i,row,col;
110*c4762a1bSJed Brown   const PetscScalar *x;
111*c4762a1bSJed Brown   PetscScalar       v;
112*c4762a1bSJed Brown   PetscErrorCode    ierr;
113*c4762a1bSJed Brown 
114*c4762a1bSJed Brown   ierr = VecGetSize(X,&N);CHKERRQ(ierr);
115*c4762a1bSJed Brown   ierr = VecGetArrayRead(X,&x);CHKERRQ(ierr);
116*c4762a1bSJed Brown 
117*c4762a1bSJed Brown   /* Calculate Jacobian */
118*c4762a1bSJed Brown   for (i=0; i<N; ++i) {
119*c4762a1bSJed Brown     row = i;
120*c4762a1bSJed Brown     col = i;
121*c4762a1bSJed Brown     v = 2*x[i];
122*c4762a1bSJed Brown     ierr = MatSetValues(jac,1,&row,1,&col,&v,INSERT_VALUES);CHKERRQ(ierr);
123*c4762a1bSJed Brown   }
124*c4762a1bSJed Brown   ierr = VecRestoreArrayRead(X,&x);CHKERRQ(ierr);
125*c4762a1bSJed Brown   ierr = MatAssemblyBegin(jac,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
126*c4762a1bSJed Brown   ierr = MatAssemblyEnd(jac,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
127*c4762a1bSJed Brown 
128*c4762a1bSJed Brown   if (jac != J) {
129*c4762a1bSJed Brown     ierr = MatAssemblyBegin(J,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
130*c4762a1bSJed Brown     ierr = MatAssemblyEnd(J,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
131*c4762a1bSJed Brown   }
132*c4762a1bSJed Brown   return 0;
133*c4762a1bSJed Brown }
134*c4762a1bSJed Brown 
135*c4762a1bSJed Brown /*TEST
136*c4762a1bSJed Brown 
137*c4762a1bSJed Brown    build:
138*c4762a1bSJed Brown       requires: !single !define(PETSC_HAVE_SUN_CXX) !complex
139*c4762a1bSJed Brown 
140*c4762a1bSJed Brown    test:
141*c4762a1bSJed Brown       args:  -snes_monitor_solution -snes_linesearch_monitor
142*c4762a1bSJed Brown 
143*c4762a1bSJed Brown TEST*/
144*c4762a1bSJed Brown 
145