Date: 2021-03-03T22:28:17+00:00

Actual source code: ex1.c
petsc-3.14.5 2021-03-03
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      1: static char help[] = "One-Shot Multigrid for Parameter Estimation Problem for the Poisson Equation.\n\
      2: Using the Interior Point Method.\n\n\n";

We are solving the parameter estimation problem for the Laplacian. We will ask to minimize a Lagrangian
function over $a$ and $u$, given by
\begin{align}
L(u, a, \lambda) = \frac{1}{2} || Qu - d ||^2 + \frac{1}{2} || L (a - a_r) ||^2 + \lambda F(u; a)
\end{align}
where $Q$ is a sampling operator, $L$ is a regularization operator, $F$ defines the PDE.
Currently, we have perfect information, meaning $Q = I$, and then we need no regularization, $L = I$. We
also give the exact control for the reference $a_r$.
The PDE will be the Laplace equation with homogeneous boundary conditions
\begin{align}
-nabla \cdot a \nabla u = f
\end{align}

     22: #include <petsc.h>
     23: #include <petscfe.h>

     25: typedef enum {RUN_FULL, RUN_TEST} RunType;

     27: typedef struct {
     28:   RunType runType;  /* Whether to run tests, or solve the full problem */
     29: } AppCtx;

     31: static PetscErrorCode ProcessOptions(MPI_Comm comm, AppCtx *options)
     32: {
     33:   const char    *runTypes[2] = {"full", "test"};
     34:   PetscInt       run;

     38:   options->runType = RUN_FULL;

     40:   PetscOptionsBegin(comm, "", "Inverse Problem Options", "DMPLEX");
     41:   run  = options->runType;
     42:   PetscOptionsEList("-run_type", "The run type", "ex1.c", runTypes, 2, runTypes[options->runType], &run, NULL);
     43:   options->runType = (RunType) run;
     44:   PetscOptionsEnd();
     45:   return(0);
     46: }

     48: static PetscErrorCode CreateMesh(MPI_Comm comm, AppCtx *user, DM *dm)
     49: {
     50:   DM             distributedMesh = NULL;

     54:   DMPlexCreateBoxMesh(comm, 2, PETSC_TRUE, NULL, NULL, NULL, NULL, PETSC_TRUE, dm);
     55:   PetscObjectSetName((PetscObject) *dm, "Mesh");
     56:   DMPlexDistribute(*dm, 0, NULL, &distributedMesh);
     57:   if (distributedMesh) {
     58:     DMDestroy(dm);
     59:     *dm  = distributedMesh;
     60:   }
     61:   DMSetFromOptions(*dm);
     62:   DMViewFromOptions(*dm, NULL, "-dm_view");
     63:   return(0);
     64: }

     66: /* u - (x^2 + y^2) */
     67: void f0_u(PetscInt dim, PetscInt Nf, PetscInt NfAux,
     68:           const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
     69:           const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
     70:           PetscReal t, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
     71: {
     72:   f0[0] = u[0] - (x[0]*x[0] + x[1]*x[1]);
     73: }
     74: /* a \nabla\lambda */
     75: void f1_u(PetscInt dim, PetscInt Nf, PetscInt NfAux,
     76:           const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
     77:           const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
     78:           PetscReal t, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f1[])
     79: {
     80:   PetscInt d;
     81:   for (d = 0; d < dim; ++d) f1[d] = u[1]*u_x[dim*2+d];
     82: }
     83: /* I */
     84: void g0_uu(PetscInt dim, PetscInt Nf, PetscInt NfAux,
     85:            const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
     86:            const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
     87:            PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g0[])
     88: {
     89:   g0[0] = 1.0;
     90: }
     91: /* \nabla */
     92: void g2_ua(PetscInt dim, PetscInt Nf, PetscInt NfAux,
     93:            const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
     94:            const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
     95:            PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g2[])
     96: {
     97:   PetscInt d;
     98:   for (d = 0; d < dim; ++d) g2[d] = u_x[dim*2+d];
     99: }
    100: /* a */
    101: void g3_ul(PetscInt dim, PetscInt Nf, PetscInt NfAux,
    102:            const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
    103:            const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
    104:            PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g3[])
    105: {
    106:   PetscInt d;
    107:   for (d = 0; d < dim; ++d) g3[d*dim+d] = u[1];
    108: }
    109: /* a - (x + y) */
    110: void f0_a(PetscInt dim, PetscInt Nf, PetscInt NfAux,
    111:           const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
    112:           const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
    113:           PetscReal t, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
    114: {
    115:   f0[0] = u[1] - (x[0] + x[1]);
    116: }
    117: /* \lambda \nabla u */
    118: void f1_a(PetscInt dim, PetscInt Nf, PetscInt NfAux,
    119:           const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
    120:           const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
    121:           PetscReal t, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f1[])
    122: {
    123:   PetscInt d;
    124:   for (d = 0; d < dim; ++d) f1[d] = u[2]*u_x[d];
    125: }
    126: /* I */
    127: void g0_aa(PetscInt dim, PetscInt Nf, PetscInt NfAux,
    128:            const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
    129:            const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
    130:            PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g0[])
    131: {
    132:   g0[0] = 1.0;
    133: }
    134: /* 6 (x + y) */
    135: void f0_l(PetscInt dim, PetscInt Nf, PetscInt NfAux,
    136:           const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
    137:           const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
    138:           PetscReal t, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[])
    139: {
    140:   f0[0] = 6.0*(x[0] + x[1]);
    141: }
    142: /* a \nabla u */
    143: void f1_l(PetscInt dim, PetscInt Nf, PetscInt NfAux,
    144:           const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
    145:           const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
    146:           PetscReal t, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f1[])
    147: {
    148:   PetscInt d;
    149:   for (d = 0; d < dim; ++d) f1[d] = u[1]*u_x[d];
    150: }
    151: /* \nabla u */
    152: void g2_la(PetscInt dim, PetscInt Nf, PetscInt NfAux,
    153:            const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
    154:            const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
    155:            PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g2[])
    156: {
    157:   PetscInt d;
    158:   for (d = 0; d < dim; ++d) g2[d] = u_x[d];
    159: }
    160: /* a */
    161: void g3_lu(PetscInt dim, PetscInt Nf, PetscInt NfAux,
    162:            const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
    163:            const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
    164:            PetscReal t, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g3[])
    165: {
    166:   PetscInt d;
    167:   for (d = 0; d < dim; ++d) g3[d*dim+d] = u[1];
    168: }

    170: /*
    171:   In 2D for Dirichlet conditions with a variable coefficient, we use exact solution:

    173:     u  = x^2 + y^2
    174:     f  = 6 (x + y)
    175:     kappa(a) = a = (x + y)

    177:   so that

    179:     -\div \kappa(a) \grad u + f = -6 (x + y) + 6 (x + y) = 0
    180: */
    181: PetscErrorCode quadratic_u_2d(PetscInt dim, PetscReal t, const PetscReal x[], PetscInt Nf, PetscScalar *u, void *ctx)
    182: {
    183:   *u = x[0]*x[0] + x[1]*x[1];
    184:   return 0;
    185: }
    186: PetscErrorCode linear_a_2d(PetscInt dim, PetscReal t, const PetscReal x[], PetscInt Nf, PetscScalar *a, void *ctx)
    187: {
    188:   *a = x[0] + x[1];
    189:   return 0;
    190: }
    191: PetscErrorCode zero(PetscInt dim, PetscReal t, const PetscReal x[], PetscInt Nf, PetscScalar *l, void *ctx)
    192: {
    193:   *l = 0.0;
    194:   return 0;
    195: }

    197: PetscErrorCode SetupProblem(DM dm, AppCtx *user)
    198: {
    199:   PetscDS        prob;
    200:   const PetscInt id = 1;

    204:   DMGetDS(dm, &prob);
    205:   PetscDSSetResidual(prob, 0, f0_u, f1_u);
    206:   PetscDSSetResidual(prob, 1, f0_a, f1_a);
    207:   PetscDSSetResidual(prob, 2, f0_l, f1_l);
    208:   PetscDSSetJacobian(prob, 0, 0, g0_uu, NULL, NULL, NULL);
    209:   PetscDSSetJacobian(prob, 0, 1, NULL, NULL, g2_ua, NULL);
    210:   PetscDSSetJacobian(prob, 0, 2, NULL, NULL, NULL, g3_ul);
    211:   PetscDSSetJacobian(prob, 1, 1, g0_aa, NULL, NULL, NULL);
    212:   PetscDSSetJacobian(prob, 2, 1, NULL, NULL, g2_la, NULL);
    213:   PetscDSSetJacobian(prob, 2, 0, NULL, NULL, NULL, g3_lu);

    215:   PetscDSSetExactSolution(prob, 0, quadratic_u_2d, NULL);
    216:   PetscDSSetExactSolution(prob, 1, linear_a_2d, NULL);
    217:   PetscDSSetExactSolution(prob, 2, zero, NULL);
    218:   DMAddBoundary(dm, DM_BC_ESSENTIAL, "wall", "marker", 0, 0, NULL, (void (*)(void)) quadratic_u_2d, NULL, 1, &id, user);
    219:   DMAddBoundary(dm, DM_BC_ESSENTIAL, "wall", "marker", 1, 0, NULL, (void (*)(void)) linear_a_2d, NULL, 1, &id, user);
    220:   DMAddBoundary(dm, DM_BC_ESSENTIAL, "wall", "marker", 2, 0, NULL, (void (*)(void)) zero, NULL, 1, &id, user);
    221:   return(0);
    222: }

    224: PetscErrorCode SetupDiscretization(DM dm, AppCtx *user)
    225: {
    226:   DM              cdm = dm;
    227:   const PetscInt  dim = 2;
    228:   PetscFE         fe[3];
    229:   PetscInt        f;
    230:   MPI_Comm        comm;
    231:   PetscErrorCode  ierr;

    234:   /* Create finite element */
    235:   PetscObjectGetComm((PetscObject) dm, &comm);
    236:   PetscFECreateDefault(comm, dim, 1, PETSC_TRUE, "potential_", -1, &fe[0]);
    237:   PetscObjectSetName((PetscObject) fe[0], "potential");
    238:   PetscFECreateDefault(comm, dim, 1, PETSC_TRUE, "conductivity_", -1, &fe[1]);
    239:   PetscObjectSetName((PetscObject) fe[1], "conductivity");
    240:   PetscFECopyQuadrature(fe[0], fe[1]);
    241:   PetscFECreateDefault(comm, dim, 1, PETSC_TRUE, "multiplier_", -1, &fe[2]);
    242:   PetscObjectSetName((PetscObject) fe[2], "multiplier");
    243:   PetscFECopyQuadrature(fe[0], fe[2]);
    244:   /* Set discretization and boundary conditions for each mesh */
    245:   for (f = 0; f < 3; ++f) {DMSetField(dm, f, NULL, (PetscObject) fe[f]);}
    246:   DMCreateDS(dm);
    247:   SetupProblem(dm, user);
    248:   while (cdm) {
    249:     DMCopyDisc(dm, cdm);
    250:     DMGetCoarseDM(cdm, &cdm);
    251:   }
    252:   for (f = 0; f < 3; ++f) {PetscFEDestroy(&fe[f]);}
    253:   return(0);
    254: }

    256: int main(int argc, char **argv)
    257: {
    258:   DM             dm;
    259:   SNES           snes;
    260:   Vec            u, r;
    261:   AppCtx         user;

    264:   PetscInitialize(&argc, &argv, NULL,help);if (ierr) return ierr;
    265:   ProcessOptions(PETSC_COMM_WORLD, &user);
    266:   SNESCreate(PETSC_COMM_WORLD, &snes);
    267:   CreateMesh(PETSC_COMM_WORLD, &user, &dm);
    268:   SNESSetDM(snes, dm);
    269:   SetupDiscretization(dm, &user);

    271:   DMCreateGlobalVector(dm, &u);
    272:   PetscObjectSetName((PetscObject) u, "solution");
    273:   VecDuplicate(u, &r);
    274:   DMPlexSetSNESLocalFEM(dm,&user,&user,&user);
    275:   SNESSetFromOptions(snes);

    277:   DMSNESCheckFromOptions(snes, u);
    278:   if (user.runType == RUN_FULL) {
    279:     PetscDS          ds;
    280:     PetscErrorCode (*exactFuncs[3])(PetscInt dim, PetscReal t, const PetscReal x[], PetscInt Nf, PetscScalar *u, void *ctx);
    281:     PetscErrorCode (*initialGuess[3])(PetscInt dim, PetscReal t, const PetscReal x[], PetscInt Nf, PetscScalar u[], void *ctx);
    282:     PetscReal        error;

    284:     DMGetDS(dm, &ds);
    285:     PetscDSGetExactSolution(ds, 0, &exactFuncs[0], NULL);
    286:     PetscDSGetExactSolution(ds, 1, &exactFuncs[1], NULL);
    287:     PetscDSGetExactSolution(ds, 2, &exactFuncs[2], NULL);
    288:     initialGuess[0] = zero;
    289:     initialGuess[1] = zero;
    290:     initialGuess[2] = zero;
    291:     DMProjectFunction(dm, 0.0, initialGuess, NULL, INSERT_VALUES, u);
    292:     VecViewFromOptions(u, NULL, "-initial_vec_view");
    293:     DMComputeL2Diff(dm, 0.0, exactFuncs, NULL, u, &error);
    294:     if (error < 1.0e-11) {PetscPrintf(PETSC_COMM_WORLD, "Initial L_2 Error: < 1.0e-11\n");}
    295:     else                 {PetscPrintf(PETSC_COMM_WORLD, "Initial L_2 Error: %g\n", error);}
    296:     SNESSolve(snes, NULL, u);
    297:     DMComputeL2Diff(dm, 0.0, exactFuncs, NULL, u, &error);
    298:     if (error < 1.0e-11) {PetscPrintf(PETSC_COMM_WORLD, "Final L_2 Error: < 1.0e-11\n");}
    299:     else                 {PetscPrintf(PETSC_COMM_WORLD, "Final L_2 Error: %g\n", error);}
    300:   }
    301:   VecViewFromOptions(u, NULL, "-sol_vec_view");

    303:   VecDestroy(&u);
    304:   VecDestroy(&r);
    305:   SNESDestroy(&snes);
    306:   DMDestroy(&dm);
    307:   PetscFinalize();
    308:   return ierr;
    309: }

    311: /*TEST

    313:   build:
    314:     requires: !complex

    316:   test:
    317:     suffix: 0
    318:     requires: triangle
    319:     args: -run_type test -dmsnes_check -potential_petscspace_degree 2 -conductivity_petscspace_degree 1 -multiplier_petscspace_degree 2

    321:   test:
    322:     suffix: 1
    323:     requires: triangle
    324:     args: -potential_petscspace_degree 2 -conductivity_petscspace_degree 1 -multiplier_petscspace_degree 2 -snes_monitor -pc_type fieldsplit -pc_fieldsplit_0_fields 0,1 -pc_fieldsplit_1_fields 2 -pc_fieldsplit_type schur -pc_fieldsplit_schur_factorization_type full -pc_fieldsplit_schur_precondition selfp -fieldsplit_0_pc_type lu -fieldsplit_multiplier_ksp_rtol 1.0e-10 -fieldsplit_multiplier_pc_type lu -sol_vec_view

    326: TEST*/