Actual source code: ex14.c

  1: static char help[] = "Tests all TSRK types \n\n";

  3: #include <petscts.h>

  5: static PetscErrorCode RHSFunction(TS ts, PetscReal t, Vec X, Vec F, PetscCtx ctx)
  6: {
  7:   PetscInt           n;
  8:   const PetscScalar *xx;
  9:   /* */ PetscScalar *ff;

 11:   PetscFunctionBeginUser;
 12:   PetscCall(VecGetLocalSize(X, &n));
 13:   PetscCall(VecGetArrayRead(X, &xx));
 14:   PetscCall(VecGetArray(F, &ff));

 16:   if (n >= 1) ff[0] = 1;
 17:   for (PetscInt i = 1; i < n; i++) ff[i] = (i + 1) * (xx[i - 1] + PetscPowReal(t, i)) / 2;

 19:   PetscCall(VecRestoreArrayRead(X, &xx));
 20:   PetscCall(VecRestoreArray(F, &ff));
 21:   PetscFunctionReturn(PETSC_SUCCESS);
 22: }

 24: PetscErrorCode TestCheckStage(TSAdapt adapt, TS ts, PetscReal t, Vec X, PetscBool *accept)
 25: {
 26:   PetscInt step;

 28:   PetscFunctionBeginUser;
 29:   PetscCall(TSGetStepNumber(ts, &step));
 30:   *accept = (step >= 2) ? PETSC_FALSE : PETSC_TRUE;
 31:   PetscFunctionReturn(PETSC_SUCCESS);
 32: }

 34: static PetscErrorCode TestExplicitTS(TS ts, PetscInt order, const char subtype[])
 35: {
 36:   PetscReal          t;
 37:   Vec                U, X, Y;
 38:   TSType             type;
 39:   PetscBool          done;
 40:   const PetscScalar *xx;
 41:   const PetscScalar *yy;
 42:   const PetscReal    Tf  = 1;
 43:   const PetscReal    dt  = Tf / 8;
 44:   const PetscReal    eps = 100 * PETSC_MACHINE_EPSILON;
 45:   TSAdapt            adapt;
 46:   PetscInt           step;
 47:   TSConvergedReason  reason;

 49:   PetscFunctionBeginUser;
 50:   PetscCall(TSGetType(ts, &type));
 51:   PetscCall(TSGetSolution(ts, &U));
 52:   PetscCall(VecZeroEntries(U));
 53:   PetscCall(TSSetStepNumber(ts, 0));
 54:   PetscCall(TSSetTime(ts, 0));
 55:   PetscCall(TSSetTimeStep(ts, dt));
 56:   PetscCall(TSSetMaxTime(ts, Tf));
 57:   PetscCall(TSSetExactFinalTime(ts, TS_EXACTFINALTIME_MATCHSTEP));
 58:   PetscCall(TSSolve(ts, NULL));
 59:   PetscCall(TSRollBack(ts));
 60:   PetscCall(TSSolve(ts, NULL));
 61:   PetscCall(TSGetTime(ts, &t));

 63:   PetscCall(TSGetSolution(ts, &U));
 64:   PetscCall(VecDuplicate(U, &X));
 65:   PetscCall(TSEvaluateStep(ts, order, X, NULL));
 66:   PetscCall(VecGetArrayRead(X, &xx));
 67:   for (PetscInt i = 0; i < order; i++) {
 68:     PetscReal error = PetscAbsReal(PetscRealPart(xx[i]) - PetscPowReal(t, i + 1));
 69:     PetscCheck(error <= eps, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Bad solution, error %g, %s '%s'", (double)error, type, subtype);
 70:   }
 71:   PetscCall(VecRestoreArrayRead(X, &xx));
 72:   PetscCall(VecDestroy(&X));

 74:   PetscCall(TSGetSolution(ts, &U));
 75:   PetscCall(VecDuplicate(U, &Y));
 76:   PetscCall(TSEvaluateStep(ts, order - 1, Y, &done));
 77:   PetscCall(VecGetArrayRead(Y, &yy));
 78:   for (PetscInt i = 0; done && i < order - 1; i++) {
 79:     PetscReal error = PetscAbsReal(PetscRealPart(yy[i]) - PetscPowReal(t, i + 1));
 80:     PetscCheck(error <= eps, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Bad estimator, error %g, %s '%s'", (double)error, type, subtype);
 81:   }
 82:   PetscCall(VecRestoreArrayRead(Y, &yy));
 83:   PetscCall(VecDestroy(&Y));

 85:   PetscCall(TSGetAdapt(ts, &adapt));
 86:   PetscCall(TSAdaptSetCheckStage(adapt, TestCheckStage));
 87:   PetscCall(TSSetErrorIfStepFails(ts, PETSC_FALSE));
 88:   PetscCall(TSSetStepNumber(ts, 0));
 89:   PetscCall(TSSetTime(ts, 0));
 90:   PetscCall(TSSetTimeStep(ts, dt));
 91:   PetscCall(TSSolve(ts, NULL));
 92:   PetscCall(TSAdaptSetCheckStage(adapt, NULL));
 93:   PetscCall(TSSetErrorIfStepFails(ts, PETSC_TRUE));
 94:   PetscCall(TSGetStepNumber(ts, &step));
 95:   PetscCall(TSGetConvergedReason(ts, &reason));
 96:   PetscCheck(step == 2, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Bad step number %" PetscInt_FMT ", %s '%s'", step, type, subtype);
 97:   PetscCheck(reason == TS_DIVERGED_STEP_REJECTED, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Bad reason %s, %s '%s'", TSConvergedReasons[reason], type, subtype);
 98:   PetscFunctionReturn(PETSC_SUCCESS);
 99: }

101: static PetscErrorCode TestTSRK(TS ts, TSRKType type)
102: {
103:   PetscInt    order;
104:   TSAdapt     adapt;
105:   PetscBool   rk1, rk3, rk4;
106:   TSAdaptType adapttype;
107:   char        savetype[32];

109:   PetscFunctionBeginUser;
110:   PetscCall(TSRKSetType(ts, type));
111:   PetscCall(TSRKGetType(ts, &type));
112:   PetscCall(TSRKGetOrder(ts, &order));

114:   PetscCall(TSGetAdapt(ts, &adapt));
115:   PetscCall(TSAdaptGetType(adapt, &adapttype));
116:   PetscCall(PetscStrncpy(savetype, adapttype, sizeof(savetype)));
117:   PetscCall(PetscStrcmp(type, TSRK1FE, &rk1));
118:   PetscCall(PetscStrcmp(type, TSRK3, &rk3));
119:   PetscCall(PetscStrcmp(type, TSRK4, &rk4));
120:   if (rk1 || rk3 || rk4) PetscCall(TSAdaptSetType(adapt, TSADAPTNONE));

122:   PetscCall(TestExplicitTS(ts, order, type));

124:   PetscCall(TSGetAdapt(ts, &adapt));
125:   PetscCall(TSAdaptSetType(adapt, savetype));
126:   PetscFunctionReturn(PETSC_SUCCESS);
127: }

129: int main(int argc, char *argv[])
130: {
131:   TS       ts;
132:   Vec      X;
133:   PetscInt N = 9;

135:   PetscFunctionBeginUser;
136:   PetscCall(PetscInitialize(&argc, &argv, NULL, help));

138:   PetscCall(TSCreate(PETSC_COMM_SELF, &ts));
139:   PetscCall(TSSetType(ts, TSRK));
140:   PetscCall(TSSetRHSFunction(ts, NULL, RHSFunction, NULL));
141:   PetscCall(VecCreateSeq(PETSC_COMM_SELF, N, &X));
142:   PetscCall(TSSetSolution(ts, X));
143:   PetscCall(VecDestroy(&X));
144:   PetscCall(TSSetFromOptions(ts));

146:   PetscCall(TestTSRK(ts, TSRK1FE));
147:   PetscCall(TestTSRK(ts, TSRK2A));
148:   PetscCall(TestTSRK(ts, TSRK3));
149:   PetscCall(TestTSRK(ts, TSRK3BS));
150:   PetscCall(TestTSRK(ts, TSRK4));
151:   PetscCall(TestTSRK(ts, TSRK5F));
152:   PetscCall(TestTSRK(ts, TSRK5DP));
153:   PetscCall(TestTSRK(ts, TSRK5BS));
154:   PetscCall(TestTSRK(ts, TSRK6VR));
155:   PetscCall(TestTSRK(ts, TSRK7VR));
156:   PetscCall(TestTSRK(ts, TSRK8VR));

158:   PetscCall(TSRollBack(ts));
159:   PetscCall(TSDestroy(&ts));

161:   PetscCall(PetscFinalize());
162:   return 0;
163: }

165: /*TEST

167: testset:
168:   output_file: output/empty.out
169:   test:
170:     suffix: 0
171:     requires: !single
172:   test:
173:     suffix: 1
174:     args: -ts_adapt_type none
175:   test:
176:     suffix: 2
177:     requires: !single
178:     args: -ts_adapt_type basic
179:   test:
180:     suffix: 3
181:     args: -ts_adapt_type dsp

183: TEST*/