Date: 2025-03-28T21:11:19+00:00

Actual source code: ex3.c

      1: static char help[] = "Basic equation for generator stability analysis.\n";

      3: /*F

      5: \begin{eqnarray}
      6:                  \frac{d \theta}{dt} = \omega_b (\omega - \omega_s)
      7:                  \frac{2 H}{\omega_s}\frac{d \omega}{dt} & = & P_m - P_max \sin(\theta) -D(\omega - \omega_s)\\
      8: \end{eqnarray}

     10:   Ensemble of initial conditions
     11:    ./ex3 -ensemble -ts_monitor_draw_solution_phase -1,-3,3,3      -ts_adapt_dt_max .01  -ts_monitor -ts_type rosw -pc_type lu -ksp_type preonly

     13:   Fault at .1 seconds
     14:    ./ex3           -ts_monitor_draw_solution_phase .42,.95,.6,1.05 -ts_adapt_dt_max .01  -ts_monitor -ts_type rosw -pc_type lu -ksp_type preonly

     16:   Initial conditions same as when fault is ended
     17:    ./ex3 -u 0.496792,1.00932 -ts_monitor_draw_solution_phase .42,.95,.6,1.05  -ts_adapt_dt_max .01  -ts_monitor -ts_type rosw -pc_type lu -ksp_type preonly

     19: F*/

     21: /*
     22:    Include "petscts.h" so that we can use TS solvers.  Note that this
     23:    file automatically includes:
     24:      petscsys.h       - base PETSc routines   petscvec.h - vectors
     25:      petscmat.h - matrices
     26:      petscis.h     - index sets            petscksp.h - Krylov subspace methods
     27:      petscviewer.h - viewers               petscpc.h  - preconditioners
     28:      petscksp.h   - linear solvers
     29: */

     31: #include <petscts.h>
     32: #include "ex3.h"

     34: int main(int argc, char **argv)
     35: {
     36:   TS           ts; /* ODE integrator */
     37:   Vec          U;  /* solution will be stored here */
     38:   Mat          A;  /* Jacobian matrix */
     39:   PetscMPIInt  size;
     40:   PetscInt     n = 2;
     41:   AppCtx       ctx;
     42:   PetscScalar *u;
     43:   PetscReal    du[2]    = {0.0, 0.0};
     44:   PetscBool    ensemble = PETSC_FALSE, flg1, flg2;
     45:   PetscInt     direction[2];
     46:   PetscBool    terminate[2];

     48:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     49:      Initialize program
     50:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     51:   PetscFunctionBeginUser;
     52:   PetscCall(PetscInitialize(&argc, &argv, NULL, help));
     53:   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
     54:   PetscCheck(size == 1, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "Only for sequential runs");

     56:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     57:     Create necessary matrix and vectors
     58:     - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     59:   PetscCall(MatCreate(PETSC_COMM_WORLD, &A));
     60:   PetscCall(MatSetSizes(A, n, n, PETSC_DETERMINE, PETSC_DETERMINE));
     61:   PetscCall(MatSetType(A, MATDENSE));
     62:   PetscCall(MatSetFromOptions(A));
     63:   PetscCall(MatSetUp(A));

     65:   PetscCall(MatCreateVecs(A, &U, NULL));

     67:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     68:     Set runtime options
     69:     - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     70:   PetscOptionsBegin(PETSC_COMM_WORLD, NULL, "Swing equation options", "");
     71:   {
     72:     ctx.omega_b = 1.0;
     73:     ctx.omega_s = 2.0 * PETSC_PI * 60.0;
     74:     ctx.H       = 5.0;
     75:     PetscCall(PetscOptionsScalar("-Inertia", "", "", ctx.H, &ctx.H, NULL));
     76:     ctx.D = 5.0;
     77:     PetscCall(PetscOptionsScalar("-D", "", "", ctx.D, &ctx.D, NULL));
     78:     ctx.E        = 1.1378;
     79:     ctx.V        = 1.0;
     80:     ctx.X        = 0.545;
     81:     ctx.Pmax     = ctx.E * ctx.V / ctx.X;
     82:     ctx.Pmax_ini = ctx.Pmax;
     83:     PetscCall(PetscOptionsScalar("-Pmax", "", "", ctx.Pmax, &ctx.Pmax, NULL));
     84:     ctx.Pm = 0.9;
     85:     PetscCall(PetscOptionsScalar("-Pm", "", "", ctx.Pm, &ctx.Pm, NULL));
     86:     ctx.tf  = 1.0;
     87:     ctx.tcl = 1.05;
     88:     PetscCall(PetscOptionsReal("-tf", "Time to start fault", "", ctx.tf, &ctx.tf, NULL));
     89:     PetscCall(PetscOptionsReal("-tcl", "Time to end fault", "", ctx.tcl, &ctx.tcl, NULL));
     90:     PetscCall(PetscOptionsBool("-ensemble", "Run ensemble of different initial conditions", "", ensemble, &ensemble, NULL));
     91:     if (ensemble) {
     92:       ctx.tf  = -1;
     93:       ctx.tcl = -1;
     94:     }

     96:     PetscCall(VecGetArray(U, &u));
     97:     u[0] = PetscAsinScalar(ctx.Pm / ctx.Pmax);
     98:     u[1] = 1.0;
     99:     PetscCall(PetscOptionsRealArray("-u", "Initial solution", "", u, &n, &flg1));
    100:     n = 2;
    101:     PetscCall(PetscOptionsRealArray("-du", "Perturbation in initial solution", "", du, &n, &flg2));
    102:     u[0] += du[0];
    103:     u[1] += du[1];
    104:     PetscCall(VecRestoreArray(U, &u));
    105:     if (flg1 || flg2) {
    106:       ctx.tf  = -1;
    107:       ctx.tcl = -1;
    108:     }
    109:   }
    110:   PetscOptionsEnd();

    112:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    113:      Create timestepping solver context
    114:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
    115:   PetscCall(TSCreate(PETSC_COMM_WORLD, &ts));
    116:   PetscCall(TSSetProblemType(ts, TS_NONLINEAR));
    117:   PetscCall(TSSetType(ts, TSTHETA));
    118:   PetscCall(TSSetEquationType(ts, TS_EQ_IMPLICIT));
    119:   PetscCall(TSARKIMEXSetFullyImplicit(ts, PETSC_TRUE));
    120:   PetscCall(TSSetIFunction(ts, NULL, (TSIFunctionFn *)IFunction, &ctx));
    121:   PetscCall(TSSetIJacobian(ts, A, A, (TSIJacobianFn *)IJacobian, &ctx));

    123:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    124:      Set initial conditions
    125:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
    126:   PetscCall(TSSetSolution(ts, U));

    128:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    129:      Set solver options
    130:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
    131:   PetscCall(TSSetMaxTime(ts, 35.0));
    132:   PetscCall(TSSetExactFinalTime(ts, TS_EXACTFINALTIME_MATCHSTEP));
    133:   PetscCall(TSSetTimeStep(ts, .1));
    134:   PetscCall(TSSetFromOptions(ts));

    136:   direction[0] = direction[1] = 1;
    137:   terminate[0] = terminate[1] = PETSC_FALSE;

    139:   PetscCall(TSSetEventHandler(ts, 2, direction, terminate, EventFunction, PostEventFunction, (void *)&ctx));

    141:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    142:      Solve nonlinear system
    143:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
    144:   if (ensemble) {
    145:     for (du[1] = -2.5; du[1] <= .01; du[1] += .1) {
    146:       PetscCall(VecGetArray(U, &u));
    147:       u[0] = PetscAsinScalar(ctx.Pm / ctx.Pmax);
    148:       u[1] = ctx.omega_s;
    149:       u[0] += du[0];
    150:       u[1] += du[1];
    151:       PetscCall(VecRestoreArray(U, &u));
    152:       PetscCall(TSSetTimeStep(ts, .01));
    153:       PetscCall(TSSolve(ts, U));
    154:     }
    155:   } else {
    156:     PetscCall(TSSolve(ts, U));
    157:   }
    158:   PetscCall(VecView(U, PETSC_VIEWER_STDOUT_WORLD));
    159:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    160:      Free work space.  All PETSc objects should be destroyed when they are no longer needed.
    161:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
    162:   PetscCall(MatDestroy(&A));
    163:   PetscCall(VecDestroy(&U));
    164:   PetscCall(TSDestroy(&ts));
    165:   PetscCall(PetscFinalize());
    166:   return 0;
    167: }

    169: /*TEST

    171:    build:
    172:      requires: !complex !single

    174:    test:
    175:       args: -nox

    177: TEST*/