add Options(options; kws...) for inheriting from an existing options set (#1172)

* add `Options(options; kws...)` for inheriting from an existing options-set with overrides

* bump to v1.13.0

* avoid copying list of arguments

* Update Project.toml

---------

Co-authored-by: Patrick Kofod Mogensen <[email protected]>

Author: thchr

Project.toml

@@ -1,6 +1,7 @@
 name = "Optim"
 uuid = "429524aa-4258-5aef-a3af-852621145aeb"
-version = "1.13.2"
+version = "1.14.0"
+
 
 [deps]
 Compat = "34da2185-b29b-5c13-b0c7-acf172513d20"

src/types.jl

@@ -9,7 +9,11 @@ abstract type AbstractOptimizerState end
 abstract type ZerothOrderState <: AbstractOptimizerState end
 
 """
-Configurable options with defaults (values 0 and NaN indicate unlimited):
+    Options(; opts...)
+
+Specify configurable optimizer options `opts...`. Unspecified options are set to the default
+values below (values 0 and NaN indicate unlimited):
+
 ```
 x_abstol::Real = 0.0,
 x_reltol::Real = 0.0,
@@ -37,7 +41,19 @@ show_every::Int = 1,
 callback = nothing,
 time_limit = NaN
 ```
-See http://julianlsolvers.github.io/Optim.jl/stable/#user/config/
+
+It is also possible to pass a previously defined `Options` argument as the first argument,
+i.e., as:
+
+```jl
+    Options(inherit_options; opts...)
+```
+
+Default values for unspecified `opts` will then be "inherited" from `inherit_options`. This
+can be used to modify a subset of options in a previously defined `Options` variable.
+
+For more information on individual options, see the documentaton at
+http://julianlsolvers.github.io/Optim.jl/stable/#user/config/.
 """
 struct Options{T, TCallback}
     x_abstol::T
@@ -172,6 +188,20 @@ function Options(;
     )
 end
 
+function Options(o::Options; kws...)
+    fields = fieldnames(typeof(o))
+    foreach(keys(kws)) do kw
+        if kw ∉ fields
+            error(lazy"`$kw` is not a valid keyword argument of `Options(opts; kws...)`")
+        end
+    end
+    newargs = ntuple(Val(nfields(o))) do i
+        field = fields[i]
+        get(kws, field, getfield(o, field))
+    end
+    return Options(newargs...)
+end
+
 _show_helper(output, k, v) = output * "$k = $v, "
 _show_helper(output, k, ::Nothing) = output
 

test/general/types.jl

@@ -45,4 +45,14 @@ import Compat.String
     io = IOBuffer()
     res = show(io, MIME"text/plain"(), Optim.Options(x_abstol = 10.0))
     @test String(take!(io)) |> contains("x_abstol = 10.0")
+
+    # inheriting update from previously defined `Options`
+    opts1 = Optim.Options(; x_abstol = 1e-3, f_abstol = 1e-6, iterations = 1000)
+    opts2 = Optim.Options(opts1; x_abstol = 1e-4, f_calls_limit = 100)
+    @test opts2.x_abstol == 1e-4 && opts2.x_abstol != opts1.x_abstol
+    @test opts2.f_calls_limit == 100 && opts2.f_calls_limit != opts1.f_calls_limit
+    @test opts2.f_abstol == opts1.f_abstol == 1e-6
+    @test opts2.iterations == opts1.iterations == 1000
+    @test_throws "not a valid keyword argument" Optim.Options(opts1; invalid_keyword=1)
+    @test Optim.Options(opts1) == opts1
 end