本文整理汇总了C++中TwoDScene::accumulateGradU方法的典型用法代码示例。如果您正苦于以下问题：C++ TwoDScene::accumulateGradU方法的具体用法？C++ TwoDScene::accumulateGradU怎么用？C++ TwoDScene::accumulateGradU使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类TwoDScene的用法示例。
在下文中一共展示了TwoDScene::accumulateGradU方法的2个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: stepScene
bool LinearizedImplicitEuler::stepScene( TwoDScene& scene, scalar dt )
{
VectorXs& x = scene.getX();
VectorXs& v = scene.getV();
const VectorXs& m = scene.getM();
assert(x.size() == v.size());
assert(x.size() == m.size());
// Implement implicit euler here!
VectorXs F(x.size());
F.setZero();
scene.accumulateGradU(F, dt*v, VectorXs(x.size()).setZero());
// Force is negative the energy gradient
F *= -1.0;
MatrixXs M(x.size(), x.size());
M.setZero();
for (int i=0;i<x.size();i+=2) {
M(i, i) = m[i];
M(i+1, i+1) = m[i+1];
}
MatrixXs MatQ(x.size(), x.size()); // dF/dq
MatQ.setZero();
scene.accumulateddUdxdx(MatQ, dt*v, VectorXs(x.size()).setZero());
MatrixXs MatV(x.size(), x.size()); // dF/dv
MatV.setZero();
scene.accumulateddUdxdv(MatV, dt*v, VectorXs(x.size()).setZero());
MatrixXs A = M-(dt*dt*MatQ+dt*MatV);
// Zero the force for fixed DoFs
for( int i = 0; i < scene.getNumParticles(); ++i ) if( scene.isFixed(i) ) F.segment<2>(2*i).setZero();
for( int i = 0; i < scene.getNumParticles(); ++i ) if( scene.isFixed(i) ) {
A.row(2*i).setZero();
A.row(2*i+1).setZero();
A.col(2*i).setZero();
A.col(2*i+1).setZero();
A(2*i, 2*i) = 1;
A(2*i+1, 2*i+1) = 1;
}
VectorXs dv = A.fullPivLu().solve(dt*F);
v = v+dv;
x = x+v*dt;
return true;
}示例2: stepScene
bool ExplicitEuler::stepScene( TwoDScene& scene, scalar dt )
{
VectorXs& x = scene.getX();
VectorXs& v = scene.getV();
const VectorXs& m = scene.getM();
// if( scene.isFixed(i) ) // Determine if the ith particle is fixed
int num_particles = scene.getNumParticles();
VectorXs forces(num_particles * 2);
VectorXs dx(num_particles * 2);
VectorXs dv(num_particles * 2);
for (int i = 0; i < num_particles * 2; i++){
forces(i) = 0.0;
dx(i) = 0.0;
dv(i) = 0.0;
}
scene.accumulateGradU(forces, dx, dv);//, const VectorXs& dx, const VectorXs& dv )
for (int i = 0; i < num_particles; i++){
if (!scene.isFixed(i)){
int index = 2 * i; // even indeces of vector are x params and odd are y params
const Vector2s next_velocity(v(index) + dt*forces(index)/m(index),
v(index+1) + dt*forces(index+1)/m(index));
scene.setVelocity(i, next_velocity);
const Vector2s next_position(x(index) + dt*v(index),
x(index + 1) + dt*v(index+1));
scene.setPosition(i, next_position);
scalar kinetic_energy = 0;
text_file << step_count*dt << "\t" << scene.computeKineticEnergy() << endl;
}
}
step_count++;
return true;
}