void BaseBinaryEdge<D, E, VertexXiType, VertexXjType>::linearizeOplus()
{
VertexXiType* vi = static_cast<VertexXiType*>(_vertices[0]);
VertexXjType* vj = static_cast<VertexXjType*>(_vertices[1]);
bool iNotFixed = !(vi->fixed());
bool jNotFixed = !(vj->fixed());
if (!iNotFixed && !jNotFixed)
return;
#ifdef G2O_OPENMP
vi->lockQuadraticForm();
vj->lockQuadraticForm();
#endif
const double delta = 1e-9;
const double scalar = 1.0 / (2*delta);
ErrorVector errorBak;
ErrorVector errorBeforeNumeric = _error;
if (iNotFixed) {
//Xi - estimate the jacobian numerically
double add_vi[VertexXiType::Dimension];
std::fill(add_vi, add_vi + VertexXiType::Dimension, 0.0);
// add small step along the unit vector in each dimension
for (int d = 0; d < VertexXiType::Dimension; ++d) {
vi->push();
add_vi[d] = delta;
vi->oplus(add_vi);
computeError();
errorBak = _error;
vi->pop();
vi->push();
add_vi[d] = -delta;
vi->oplus(add_vi);
computeError();
errorBak -= _error;
vi->pop();
add_vi[d] = 0.0;
_jacobianOplusXi.col(d) = scalar * errorBak;
} // end dimension
}
if (jNotFixed) {
//Xj - estimate the jacobian numerically
double add_vj[VertexXjType::Dimension];
std::fill(add_vj, add_vj + VertexXjType::Dimension, 0.0);
// add small step along the unit vector in each dimension
for (int d = 0; d < VertexXjType::Dimension; ++d) {
vj->push();
add_vj[d] = delta;
vj->oplus(add_vj);
computeError();
errorBak = _error;
vj->pop();
vj->push();
add_vj[d] = -delta;
vj->oplus(add_vj);
computeError();
errorBak -= _error;
vj->pop();
add_vj[d] = 0.0;
_jacobianOplusXj.col(d) = scalar * errorBak;
}
} // end dimension
_error = errorBeforeNumeric;
#ifdef G2O_OPENMP
vj->unlockQuadraticForm();
vi->unlockQuadraticForm();
#endif
}
