api.jl

Base.summary(r::OptimizationResults) = summary(r.method) # might want to do more here than just return summary of the method used
minimizer(r::OptimizationResults) = r.minimizer
minimum(r::OptimizationResults) = r.minimum
iterations(r::OptimizationResults) = r.iterations
iteration_limit_reached(r::OptimizationResults) = r.iteration_converged
trace(r::OptimizationResults) = length(r.trace) > 0 ? r.trace : error("No trace in optimization results. To get a trace, run optimize() with store_trace = true.")

function x_trace(r::UnivariateOptimizationResults)
    tr = trace(r)
    !haskey(tr[1].metadata, "minimizer") && error("Trace does not contain x. To get a trace of x, run optimize() with extended_trace = true")
    [ state.metadata["minimizer"] for state in tr ]
end
function x_lower_trace(r::UnivariateOptimizationResults)
    tr = trace(r)
    !haskey(tr[1].metadata, "x_lower") && error("Trace does not contain x. To get a trace of x, run optimize() with extended_trace = true")
    [ state.metadata["x_lower"] for state in tr ]
end
x_lower_trace(r::MultivariateOptimizationResults) = error("x_lower_trace is not implemented for $(summary(r)).")
function x_upper_trace(r::UnivariateOptimizationResults)
    tr = trace(r)
    !haskey(tr[1].metadata, "x_upper") && error("Trace does not contain x. To get a trace of x, run optimize() with extended_trace = true")
    [ state.metadata["x_upper"] for state in tr ]
end
x_upper_trace(r::MultivariateOptimizationResults) = error("x_upper_trace is not implemented for $(summary(r)).")

function x_trace(r::MultivariateOptimizationResults)
    tr = trace(r)
    if isa(r.method, NelderMead)
        throw(ArgumentError("Nelder Mead does not operate with a single x. Please use either centroid_trace(...) or simplex_trace(...) to extract the relevant points from the trace."))
    end
    !haskey(tr[1].metadata, "x") && error("Trace does not contain x. To get a trace of x, run optimize() with extended_trace = true")
    [ state.metadata["x"] for state in tr ]
end

function centroid_trace(r::MultivariateOptimizationResults)
    tr = trace(r)
    if !isa(r.method, NelderMead)
        throw(ArgumentError("There is no centroid involved in optimization using $(r.method). Please use x_trace(...) to grab the points from the trace."))
    end
    !haskey(tr[1].metadata, "centroid") && error("Trace does not contain centroid. To get a trace of the centroid, run optimize() with extended_trace = true")
    [ state.metadata["centroid"] for state in tr ]
end
function simplex_trace(r::MultivariateOptimizationResults)
    tr = trace(r)
    if !isa(r.method, NelderMead)
        throw(ArgumentError("There is no simplex involved in optimization using $(r.method). Please use x_trace(...) to grab the points from the trace."))
    end
    !haskey(tr[1].metadata, "simplex") && error("Trace does not contain simplex. To get a trace of the simplex, run optimize() with trace_simplex = true")
    [ state.metadata["simplex"] for state in tr ]
end
function simplex_value_trace(r::MultivariateOptimizationResults)
    if !isa(r.method, NelderMead)
        throw(ArgumentError("There are no simplex values involved in optimization using $(r.method). Please use f_trace(...) to grab the objective values from the trace."))
    end
    !haskey(tr[1].metadata, "simplex_values") && error("Trace does not contain objective values at the simplex. To get a trace of the simplex values, run optimize() with trace_simplex = true")
    [ state.metadata["simplex_values"] for state in tr ]
end


f_trace(r::OptimizationResults) = [ state.value for state in trace(r) ]
g_norm_trace(r::OptimizationResults) = error("g_norm_trace is not implemented for $(summary(r)).")
g_norm_trace(r::MultivariateOptimizationResults) = [ state.g_norm for state in trace(r) ]

f_calls(r::OptimizationResults) = r.f_calls
f_calls(d) = first(d.f_calls)

g_calls(r::OptimizationResults) = error("g_calls is not implemented for $(summary(r)).")
g_calls(r::MultivariateOptimizationResults) = r.g_calls
g_calls(d::NonDifferentiable) = 0
g_calls(d) = first(d.df_calls)

h_calls(r::OptimizationResults) = error("h_calls is not implemented for $(summary(r)).")
h_calls(r::MultivariateOptimizationResults) = r.h_calls
h_calls(d::Union{NonDifferentiable, OnceDifferentiable}) = 0
h_calls(d) = first(d.h_calls)
h_calls(d::TwiceDifferentiableHV) = first(d.hv_calls)

converged(r::UnivariateOptimizationResults) = r.converged
function converged(r::MultivariateOptimizationResults)
    conv_flags = r.x_converged || r.f_converged || r.g_converged
    x_isfinite = isfinite(x_abschange(r)) || isnan(x_relchange(r))
    f_isfinite = if r.iterations > 0
            isfinite(f_abschange(r)) || isnan(f_relchange(r))
        else
            true
        end
    g_isfinite = isfinite(g_residual(r))
    return conv_flags && all((x_isfinite, f_isfinite, g_isfinite))
end
x_converged(r::OptimizationResults) = error("x_converged is not implemented for $(summary(r)).")
x_converged(r::MultivariateOptimizationResults) = r.x_converged
f_converged(r::OptimizationResults) = error("f_converged is not implemented for $(summary(r)).")
f_converged(r::MultivariateOptimizationResults) = r.f_converged
f_increased(r::OptimizationResults) = error("f_increased is not implemented for $(summary(r)).")
f_increased(r::MultivariateOptimizationResults) = r.f_increased
g_converged(r::OptimizationResults) = error("g_converged is not implemented for $(summary(r)).")
g_converged(r::MultivariateOptimizationResults) = r.g_converged

x_abstol(r::OptimizationResults) = error("x_abstol is not implemented for $(summary(r)).")
x_reltol(r::OptimizationResults) = error("x_reltol is not implemented for $(summary(r)).")
x_tol(r::OptimizationResults) = error("x_tol is not implemented for $(summary(r)).")
x_abstol(r::MultivariateOptimizationResults) = r.x_abstol
x_reltol(r::MultivariateOptimizationResults) = r.x_reltol
x_tol(r::MultivariateOptimizationResults) = r.x_abstol
x_abschange(r::MultivariateOptimizationResults) = r.x_abschange
x_relchange(r::MultivariateOptimizationResults) = r.x_relchange
f_abstol(r::OptimizationResults) = error("f_abstol is not implemented for $(summary(r)).")
f_reltol(r::OptimizationResults) = error("f_reltol is not implemented for $(summary(r)).")
f_tol(r::OptimizationResults) = error("f_tol is not implemented for $(summary(r)).")
f_tol(r::MultivariateOptimizationResults) = r.f_reltol
f_abstol(r::MultivariateOptimizationResults) = r.f_abstol
f_reltol(r::MultivariateOptimizationResults) = r.f_reltol
f_abschange(r::MultivariateOptimizationResults) = r.f_abschange
f_relchange(r::MultivariateOptimizationResults) = r.f_relchange

g_tol(r::OptimizationResults) = error("g_tol is not implemented for $(summary(r)).")
g_tol(r::MultivariateOptimizationResults) = r.g_abstol
g_residual(r::MultivariateOptimizationResults) = r.g_residual


initial_state(r::OptimizationResults) = error("initial_state is not implemented for $(summary(r)).")
initial_state(r::MultivariateOptimizationResults) = r.initial_x

lower_bound(r::OptimizationResults) = error("lower_bound is not implemented for $(summary(r)).")
lower_bound(r::UnivariateOptimizationResults) = r.initial_lower
upper_bound(r::OptimizationResults) = error("upper_bound is not implemented for $(summary(r)).")
upper_bound(r::UnivariateOptimizationResults) = r.initial_upper

rel_tol(r::OptimizationResults) = error("rel_tol is not implemented for $(summary(r)).")
rel_tol(r::UnivariateOptimizationResults) = r.rel_tol
abs_tol(r::OptimizationResults) = error("abs_tol is not implemented for $(summary(r)).")
abs_tol(r::UnivariateOptimizationResults) = r.abs_tol

time_limit(r::MultivariateOptimizationResults) = r.time_limit
time_run(  r::MultivariateOptimizationResults) = r.time_run

time_limit(r::OptimizationResults) = error("time_limit is not implemented for $(summary(r)).")
time_run(  r::OptimizationResults) = error("time_run is not implemented for $(summary(r)).")