1 2 static char help[] = "Transistor amplifier.\n"; 3 4 /*F 5 M y'=f(t,y) 6 7 Useful options: -ts_monitor_lg_solution -ts_monitor_lg_timestep -lg_indicate_data_points 0 8 F*/ 9 10 /* 11 Include "petscts.h" so that we can use TS solvers. Note that this 12 file automatically includes: 13 petscsys.h - base PETSc routines petscvec.h - vectors 14 petscmat.h - matrices 15 petscis.h - index sets petscksp.h - Krylov subspace methods 16 petscviewer.h - viewers petscpc.h - preconditioners 17 petscksp.h - linear solvers 18 */ 19 #include <petscts.h> 20 21 FILE *gfilepointer_data,*gfilepointer_info; 22 23 /* Defines the source */ 24 PetscErrorCode Ue(PetscScalar t,PetscScalar *U) 25 { 26 PetscFunctionBegin; 27 * U = 0.4*PetscSinReal(200*PETSC_PI*t); 28 PetscFunctionReturn(0); 29 } 30 31 32 /* 33 Defines the DAE passed to the time solver 34 */ 35 static PetscErrorCode IFunctionImplicit(TS ts,PetscReal t,Vec Y,Vec Ydot,Vec F,void *ctx) 36 { 37 PetscErrorCode ierr; 38 const PetscScalar *y,*ydot; 39 PetscScalar *f; 40 41 PetscFunctionBegin; 42 /* The next three lines allow us to access the entries of the vectors directly */ 43 ierr = VecGetArrayRead(Y,&y);CHKERRQ(ierr); 44 ierr = VecGetArrayRead(Ydot,&ydot);CHKERRQ(ierr); 45 ierr = VecGetArray(F,&f);CHKERRQ(ierr); 46 47 f[0]= PetscSinReal(200*PETSC_PI*t)/2500. - y[0]/1000. - ydot[0]/1.e6 + ydot[1]/1.e6; 48 f[1]=0.0006666766666666667 - PetscExpReal((500*(y[1] - y[2]))/13.)/1.e8 - y[1]/4500. + ydot[0]/1.e6 - ydot[1]/1.e6; 49 f[2]=-1.e-6 + PetscExpReal((500*(y[1] - y[2]))/13.)/1.e6 - y[2]/9000. - ydot[2]/500000.; 50 f[3]=0.0006676566666666666 - (99* PetscExpReal((500*(y[1] - y[2]))/13.))/1.e8 - y[3]/9000. - (3*ydot[3])/1.e6 + (3*ydot[4])/1.e6; 51 f[4]=-y[4]/9000. + (3*ydot[3])/1.e6 - (3*ydot[4])/1.e6; 52 53 ierr = VecRestoreArrayRead(Y,&y);CHKERRQ(ierr); 54 ierr = VecRestoreArrayRead(Ydot,&ydot);CHKERRQ(ierr); 55 ierr = VecRestoreArray(F,&f);CHKERRQ(ierr); 56 PetscFunctionReturn(0); 57 } 58 59 /* 60 Defines the Jacobian of the ODE passed to the ODE solver. See TSSetIJacobian() for the meaning of a and the Jacobian. 61 */ 62 static PetscErrorCode IJacobianImplicit(TS ts,PetscReal t,Vec Y,Vec Ydot,PetscReal a,Mat A,Mat B,void *ctx) 63 { 64 PetscErrorCode ierr; 65 PetscInt rowcol[] = {0,1,2,3,4}; 66 const PetscScalar *y,*ydot; 67 PetscScalar J[5][5]; 68 69 PetscFunctionBegin; 70 ierr = VecGetArrayRead(Y,&y);CHKERRQ(ierr); 71 ierr = VecGetArrayRead(Ydot,&ydot);CHKERRQ(ierr); 72 73 ierr = PetscMemzero(J,sizeof(J));CHKERRQ(ierr); 74 75 J[0][0]=-0.001 - a/1.e6; 76 J[0][1]=a/1.e6; 77 J[1][0]=a/1.e6; 78 J[1][1]=-0.00022222222222222223 - a/1.e6 - PetscExpReal((500*(y[1] - y[2]))/13.)/2.6e6; 79 J[1][2]= PetscExpReal((500*(y[1] - y[2]))/13.)/2.6e6; 80 J[2][1]= PetscExpReal((500*(y[1] - y[2]))/13.)/26000.; 81 J[2][2]=-0.00011111111111111112 - a/500000. - PetscExpReal((500*(y[1] - y[2]))/13.)/26000.; 82 J[3][1]=(-99* PetscExpReal((500*(y[1] - y[2]))/13.))/2.6e6; 83 J[3][2]=(99* PetscExpReal((500*(y[1] - y[2]))/13.))/2.6e6; 84 J[3][3]=-0.00011111111111111112 - (3*a)/1.e6; 85 J[3][4]=(3*a)/1.e6; 86 J[4][3]=(3*a)/1.e6; 87 J[4][4]=-0.00011111111111111112 - (3*a)/1.e6; 88 89 90 ierr = MatSetValues(B,5,rowcol,5,rowcol,&J[0][0],INSERT_VALUES);CHKERRQ(ierr); 91 92 ierr = VecRestoreArrayRead(Y,&y);CHKERRQ(ierr); 93 ierr = VecRestoreArrayRead(Ydot,&ydot);CHKERRQ(ierr); 94 95 ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); 96 ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); 97 if (A != B) { 98 ierr = MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); 99 ierr = MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); 100 } 101 PetscFunctionReturn(0); 102 } 103 104 int main(int argc,char **argv) 105 { 106 TS ts; /* ODE integrator */ 107 Vec Y; /* solution will be stored here */ 108 Mat A; /* Jacobian matrix */ 109 PetscErrorCode ierr; 110 PetscMPIInt size; 111 PetscInt n = 5; 112 PetscScalar *y; 113 114 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 115 Initialize program 116 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ 117 ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr; 118 ierr = MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRQ(ierr); 119 if (size > 1) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP,"Only for sequential runs"); 120 121 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 122 Create necessary matrix and vectors 123 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ 124 ierr = MatCreate(PETSC_COMM_WORLD,&A);CHKERRQ(ierr); 125 ierr = MatSetSizes(A,n,n,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr); 126 ierr = MatSetFromOptions(A);CHKERRQ(ierr); 127 ierr = MatSetUp(A);CHKERRQ(ierr); 128 129 ierr = MatCreateVecs(A,&Y,NULL);CHKERRQ(ierr); 130 131 ierr = VecGetArray(Y,&y);CHKERRQ(ierr); 132 y[0] = 0.0; 133 y[1] = 3.0; 134 y[2] = y[1]; 135 y[3] = 6.0; 136 y[4] = 0.0; 137 ierr = VecRestoreArray(Y,&y);CHKERRQ(ierr); 138 139 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 140 Create timestepping solver context 141 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ 142 ierr = TSCreate(PETSC_COMM_WORLD,&ts);CHKERRQ(ierr); 143 ierr = TSSetProblemType(ts,TS_NONLINEAR);CHKERRQ(ierr); 144 ierr = TSSetType(ts,TSARKIMEX);CHKERRQ(ierr); 145 ierr = TSSetEquationType(ts,TS_EQ_DAE_IMPLICIT_INDEX1);CHKERRQ(ierr); 146 ierr = TSARKIMEXSetFullyImplicit(ts,PETSC_TRUE);CHKERRQ(ierr); 147 /*ierr = TSSetType(ts,TSROSW);CHKERRQ(ierr);*/ 148 ierr = TSSetIFunction(ts,NULL,IFunctionImplicit,NULL);CHKERRQ(ierr); 149 ierr = TSSetIJacobian(ts,A,A,IJacobianImplicit,NULL);CHKERRQ(ierr); 150 151 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 152 Set initial conditions 153 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ 154 ierr = TSSetSolution(ts,Y);CHKERRQ(ierr); 155 156 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 157 Set solver options 158 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ 159 ierr = TSSetMaxTime(ts,0.15);CHKERRQ(ierr); 160 ierr = TSSetExactFinalTime(ts,TS_EXACTFINALTIME_STEPOVER);CHKERRQ(ierr); 161 ierr = TSSetTimeStep(ts,.001);CHKERRQ(ierr); 162 ierr = TSSetFromOptions(ts);CHKERRQ(ierr); 163 164 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 165 Do time stepping 166 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ 167 ierr = TSSolve(ts,Y);CHKERRQ(ierr); 168 169 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 170 Free work space. All PETSc objects should be destroyed when they are no longer needed. 171 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ 172 ierr = MatDestroy(&A);CHKERRQ(ierr); 173 ierr = VecDestroy(&Y);CHKERRQ(ierr); 174 ierr = TSDestroy(&ts);CHKERRQ(ierr); 175 ierr = PetscFinalize(); 176 return ierr; 177 } 178 179 /*TEST 180 build: 181 requires: !single !complex 182 test: 183 184 TEST*/ 185