LSAtTmod.jl

"""
Type: LSAtT

Methods: update!, reinit!, copy

A structure designed to track line search information from one iteration to
another. If we have f : ℜⁿ → ℜ, then we define h(θ) = f(x + θ*d) where x and d
are vectors of same dimension and θ is a scalar, more specifically our step size.

Tracked data can include:
 - x : our current step size
 - ht : h(θ) at the current iteration
 - gt : h'(θ)
 - h₀ : h(0)
 - g₀ : h'(0)
 - current_time:  the time at which the line search algorithm started.
 - current_score: the score at which the line search algorithm started.

Note: by default, unknown entries are set to nothing.
"""
mutable struct 	LSAtT <: AbstractState

    x            :: Number
    ht           :: FloatVoid  # h(θ)
    gt           :: FloatVoid  # h'(θ)
    h₀           :: FloatVoid  # h(0)
    g₀           :: FloatVoid  # h'(0)

    current_time   :: FloatVoid
    current_score  :: FloatVoid

 function LSAtT(t             :: Number;
                ht            :: FloatVoid = nothing,
                gt            :: FloatVoid = nothing,
                h₀            :: FloatVoid = nothing,
                g₀            :: FloatVoid = nothing,
                current_time  :: FloatVoid = nothing,
                current_score :: FloatVoid = nothing)

  return new(t, ht, gt, h₀, g₀, current_time, current_score)
 end
end

import Base.copy
"""
copy: Copy a LSAtT
"""
function copy(ls_at_t :: LSAtT)
    return LSAtT(copy(ls_at_t.x),
                 ht = copy(ls_at_t.ht),
                 gt = copy(ls_at_t.gt),
                 h₀ = copy(ls_at_t.h₀),
                 g₀ = copy(ls_at_t.g₀),
                 current_time = copy(ls_at_t.current_time),
                 current_score = copy(ls_at_t.current_score))
end