// Iterate mutates m and so for each iteration, the same, mutated m should be
// passed in.
func (m *Method) Iterate(o optim.Objectiver, mesh optim.Mesh) (best *optim.Point, n int, err error) {
if m.count == 0 {
m.origstep = mesh.Step()
} else if mesh.Step() < m.ResetStep {
mesh.SetStep(m.ResetStepSize)
}
var nevalsearch, nevalpoll int
var success bool
defer m.updateDb(&nevalsearch, &nevalpoll, mesh.Step())
m.count++
prevstep := mesh.Step()
if !m.DiscreteSearch {
mesh.SetStep(0)
}
success, best, nevalsearch, err = m.Searcher.Search(o, mesh, m.Curr)
mesh.SetStep(prevstep)
n += nevalsearch
if success {
m.Curr = best
return best, n, err
}
// It is important to recenter mesh on new best point before polling.
// This is necessary because the search may not be operating on the
// current mesh grid. This doesn't need to happen if search succeeds
// because search either always operates on the same grid, or always
// operates in continuous space.
mesh.SetOrigin(m.Curr.Pos) // TODO: test that this doesn't get set to Zero pos [0 0 0...] on first iteration.
var err2 error
success, best, nevalpoll, err2 = m.Poller.Poll(o, m.ev, mesh, m.Curr)
m.Poller.Spanner.Update(mesh.Step(), success)
n += nevalpoll
if success {
m.Curr = best
m.nsuccess++
if m.nsuccess == m.NsuccessGrow { // == allows -1 to mean never grow
mesh.SetStep(mesh.Step() / m.StepMult)
m.nsuccess = 0 // reset after resize
}
// Important to recenter mesh on new best point. More particularly,
// the mesh may have been resized and the new best may not lie on the
// previous mesh grid.
mesh.SetOrigin(best.Pos)
return best, n, collect(err, err2)
} else {
m.nsuccess = 0
if nextstep := mesh.Step() * m.StepMult; nextstep > 0 {
mesh.SetStep(mesh.Step() * m.StepMult)
}
return m.Curr, n, collect(err, err2)
}
}
