TopOpt.h

#ifndef TOPOPT_H
#define TOPOPT_H

#include <petsc.h>
//#include <petsc-private/dmdaimpl.h>
#include "MMA.h"
#include <fstream>
#include <iostream>
#include <math.h>
#include <petsc/private/dmdaimpl.h>
#include <sstream>

/*
 Authors: Niels Aage, Erik Andreassen, Boyan Lazarov, August 2013
 Updated: June 2019, Niels Aage
Copyright (C) 2013-2019,

 Disclaimer:
 The authors reserves all rights but does not guaranty that the code is
 free from errors. Furthermore, we shall not be liable in any event
 caused by the use of the program.
*/

/*
 *
 * Parameter container for the topology optimization problem
 *
 * min_x fx
 * s.t. gx_j <= 0, j=1..m
 *      xmin_i <= x_i <= xmax_i, i=1..n
 *
 * with filtering and a volume constraint
 *
 */

class TopOpt {

  public:
    // Constructor/Destructor
    TopOpt(PetscInt nconstraint);
    TopOpt();
    ~TopOpt();

    // Method to allocate MMA with/without restarting
    PetscErrorCode AllocateMMAwithRestart(PetscInt* itr, MMA** mma);
    PetscErrorCode WriteRestartFiles(PetscInt* itr, MMA* mma);

    // Physical domain variables
    PetscScalar xc[6];      // Domain coordinates
    PetscScalar dx, dy, dz; // Element size
    PetscInt    nxyz[3];    // Number of nodes in each direction
    PetscInt    nlvls;      // Number of multigrid levels
    PetscScalar nu;         // Poisson's ratio
    /* NOTE: two meshes are needed such the both
     * nodal and element mesh share the partitioning
     */
    // Nodal mesh (basis for physics)
    DM da_nodes;
    // element mesh (basis for design)
    DM da_elem;

    // Optimization parameters
    PetscInt     n;      // Total number of design variables
    PetscInt     nloc;   // Local number of local nodes?
    PetscInt     m;      // Number of constraints
    PetscScalar  fx;     // Objective value
    PetscScalar  fscale; // Scaling factor for objective
    PetscScalar* gx;     // Array with constraint values
    PetscScalar  Xmin;   // Min. value of design variables
    PetscScalar  Xmax;   // Max. value of design variables

    PetscScalar movlim;     // Max. change of design variables
    PetscScalar volfrac;    // Volume fraction
    PetscScalar penal;      // Penalization parameter
    PetscScalar Emin, Emax; // Modified SIMP, max and min E

    PetscInt maxItr; // Max iterations

    PetscScalar rmin;             // filter radius
    PetscInt    filter;           // Filter type
    PetscBool   projectionFilter; // Smooth heaviside projectionFilter
    PetscReal   beta;
    PetscReal   betaFinal;
    PetscReal   eta;

    Vec  x;          // Design variables
    Vec  xTilde;     // Filtered field
    Vec  xPhys;      // Physical variables (filtered x)
    Vec  dfdx;       // Sensitivities of objective
    Vec  xmin, xmax; // Vectors with max and min values of x
    Vec  xold;       // x from previous iteration
    Vec* dgdx;       // Sensitivities of constraints (vector array)

    // Restart data for MMA:
    PetscBool   restart, flip;
    std::string restdens_1, restdens_2;
    Vec         xo1, xo2, U, L;

  private:
    // Allocate and set default values
    void           Init();
    PetscErrorCode SetUp();

    PetscErrorCode SetUpMESH();
    PetscErrorCode SetUpOPT();

    // Restart filenames
    std::string filename00, filename00Itr, filename01, filename01Itr;

    // File existence
    inline PetscBool fexists(const std::string& filename) {
        std::ifstream ifile(filename.c_str());
        if (ifile) {
            return PETSC_TRUE;
        }
        return PETSC_FALSE;
    }
};

#endif