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#include "admmpd_solver.h"
#include "admmpd_lattice.h"
#include "admmpd_energy.h"
#include <Eigen/Geometry>
#include <Eigen/Sparse>
#include <stdio.h>
namespace admmpd {
using namespace Eigen;
template <typename T> using RowSparseMatrix = SparseMatrix<T,RowMajor>;
bool Solver::init(
const Eigen::MatrixXd &V,
const Eigen::MatrixXi &T,
const ADMMPD_Options *options,
ADMMPD_Data *data)
{
if (!data || !options)
throw std::runtime_error("init: data/options null");
data->x = V;
data->tets = T;
compute_matrices(options,data);
return true;
} // end init
void Solver::init_solve(
const ADMMPD_Options *options,
ADMMPD_Data *data)
{
double dt = std::max(0.0, options->timestep_s);
int nx = data->x.rows();
if (data->M_xbar.rows() != nx)
data->M_xbar.resize(nx,3);
// velocity and position
data->x_start = data->x;
for( int i=0; i<nx; ++i )
{
data->v.row(i) += options->grav;
data->M_xbar.row(i) =
data->m[i] * data->x.row(i) +
dt*data->m[i]*data->v.row(i);
}
// ADMM variables
data->Dx.noalias() = data->D * data->x;
data->z = data->Dx;
data->z_prev = data->z;
data->u.setZero();
data->u_prev.setZero();
} // end init solve
int Solver::solve(
const ADMMPD_Options *options,
ADMMPD_Data *data)
{
// Init the solve which computes
// quantaties like M_xbar and makes sure
// the variables are sized correctly.
init_solve(options,data);
int ne = data->rest_volumes.size();
Lame lame;
// Begin solver loop
int iters = 0;
int max_iters = options->max_iters < 0 ? 10000 : options->max_iters;
for (; iters < max_iters; ++iters)
{
// Local step
data->Dx.noalias() = data->D * data->x;
data->z_prev.noalias() = data->z;
data->u_prev.noalias() = data->u;
for(int i=0; i<ne; ++i)
{
EnergyTerm().update(
data->indices[i][0],
lame,
data->rest_volumes[i],
data->weights[i],
&data->x,
&data->Dx,
&data->z,
&data->u );
}
// Global step
data->b.noalias() = data->M_xbar + data->DtW2*(data->z-data->u);
data->x.noalias() = data->ldltA.solve(data->b);
} // end solver iters
double dt = std::max(0.0, options->timestep_s);
if (dt > 0.0)
data->v.noalias() = (data->x-data->x_start)*(1.0/dt);
return iters;
} // end solve
void Solver::compute_matrices(
const ADMMPD_Options *options,
ADMMPD_Data *data)
{
// Allocate per-vertex data
int nx = data->x.rows();
data->x_start = data->x;
data->M_xbar.resize(nx,3);
data->M_xbar.setZero();
data->Dx.resize(nx,3);
data->Dx.setZero();
if (data->v.rows() != nx)
{
data->v.resize(nx,3);
data->v.setZero();
}
if (data->m.rows() != nx)
{ // TODO get from BodyPoint
data->m.resize(nx);
data->m.setOnes();
}
// Add per-element energies to data
std::vector< Triplet<double> > trips;
append_energies(options,data,trips);
int nw = trips.back().row()+1;
// Global matrix
data->D.resize(nw,nx);
data->D.setFromTriplets(trips.begin(), trips.end());
data->Dt = data->D.transpose();
VectorXd w_diag = Map<VectorXd>(data->weights.data(), data->weights.size());
data->DtW2 = data->Dt * w_diag.asDiagonal() * w_diag.asDiagonal();
data->A = data->DtW2 * data->D;
data->A.diagonal() += data->m;
data->ldltA.compute(data->A);
data->b.resize(nx,3);
data->b.setZero();
data->z.resize(nw,3);
data->z.setZero();
data->z_prev.resize(nw,3);
data->z_prev.setZero();
data->u.resize(nw,3);
data->u.setZero();
data->u_prev.resize(nw,3);
data->u_prev.setZero();
} // end compute matrices
void Solver::append_energies(
const ADMMPD_Options *options,
ADMMPD_Data *data,
std::vector<Triplet<double> > &D_triplets)
{
int nt = data->tets.rows();
if (nt==0)
return;
data->indices.reserve(nt);
data->rest_volumes.reserve(nt);
data->weights.reserve(nt);
Lame lame;
int energy_index = 0;
for (int i=0; i<nt; ++i)
{
data->rest_volumes.emplace_back();
data->weights.emplace_back();
int energy_dim = 0;
RowVector4i ele = data->tets.row(i);
energy_dim = EnergyTerm().init_tet(
energy_index,
lame,
ele,
&data->x,
data->rest_volumes.back(),
data->weights.back(),
D_triplets );
// Error in initialization
if( energy_dim <= 0 ){
data->rest_volumes.pop_back();
data->weights.pop_back();
continue;
}
data->indices.emplace_back(energy_index, energy_dim);
energy_index += energy_dim;
}
} // end append energies
} // namespace admmpd
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