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Implement findmin, findmax, argmin, argmax 
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‎src/NaNMath.jl‎

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@@ -351,4 +351,220 @@ for f in (:min, :max)
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@eval ($f)(a, b, c, xs...) = Base.afoldl($f, ($f)(($f)(a, b), c), xs...)
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end
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# The functions `findmin`, `findmax`, `argmin`, and `argmax` are supported
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# to work correctly for the following iterable types:
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_valtype(x::AbstractArray{T}) where T<:AbstractFloat = eltype(x)
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_valtype(x::Tuple{Vararg{T} where T<:AbstractFloat}) = eltype(x)
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_valtype(x::NamedTuple{syms, <:Tuple{Vararg{T} where T<:AbstractFloat}}) where {syms} = eltype(x)
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_valtype(x::AbstractDict{K,T}) where {K,T<:AbstractFloat} = valtype(x)
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_valtype(x) = error(
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"Iterables with value type AbstractFloat or its subtypes are supported.
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The provided input type $(typeof(x)) is not.
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Consider using the convert function before passing the iterable argument."
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)
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function _find_extreme(f,compare_op::Function, x)
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result_index = 1 # Note: default index value.
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result_value = convert(_valtype(x), NaN)
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for (k, v) in pairs(x)
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if !isnan(v)
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if (isnan(result_value) || compare_op(f(v),f(result_value)))
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result_index = k
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result_value = v
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end
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end
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end
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return f(result_value), result_index
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end
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"""
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NaNMath.findmin(f, domain) -> (f(x), index)
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NaNMath.findmin(domain) -> (x, index)
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##### Args:
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* `f`: A function applied to the elements of `domain`;
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defaults to `identity` when `domain` is the only argument.
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* `domain`: A non-empty collection of floating point numbers such that
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`f` is defined on elements of `domain`.
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##### Returns:
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* Returns a `Tuple` consisting of a value `f(x)` and the index of `x`
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in `domain`, ignoring NaN's, such that `f(x)` is minimized.
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If there are multiple minimal elements, then the first one will be returned.
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If `domain` is a `NamedTuple` or dictionary-like `AbstractDict` L,
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the function is applied to its values. The returned index is a key `k`,
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such that `f(L[k])` is minimized.
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##### Examples:
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```julia
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julia> NaNMath.findmin([1., 1., 2., 2., NaN])
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(1.0, 1)
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julia> NaNMath.findmin(-, [1., 1., 2., 2., NaN])
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(-2.0, 3)
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julia> NaNMath.findmin(abs, Dict(:x => 3.0, :w => -2.2, :y => -3.0, :z => NaN))
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(2.2, :w)
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```
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"""
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function findmin end
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findmin(f,x) = _find_extreme(f,<,x)
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findmin(x) = findmin(identity,x)
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"""
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NaNMath.findmax(f, domain) -> (f(x), index)
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NaNMath.findmax(domain) -> (x, index)
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##### Args:
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* `f`: A function applied to the elements of `domain`;
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defaults to `identity` when `domain` is the only argument.
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* `domain`: A non-empty collection of floating point numbers such that
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`f` is defined on elements of `domain`.
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##### Returns:
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* Returns a `Tuple` consisting of a value `f(x)` and the index of `x`
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in `domain`, ignoring NaN's, such that `f(x)` is maximized.
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If there are multiple maximal elements, then the first one will be returned.
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If `domain` is a `NamedTuple` or dictionary-like `AbstractDict` L,
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the function `f` is applied to its values. The returned index is a key `k`,
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such that `f(L[k])` is maximized.
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##### Examples:
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```julia
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julia> NaNMath.findmax([1., 1., 2., 2., NaN])
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(2.0, 3)
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julia> NaNMath.findmax(-, [1., 1., 2., 2., NaN])
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(-1.0, 1)
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julia> NaNMath.findmax(abs, Dict(:x => 3.0, :w => -2.2, :y => -3.0, :z => NaN))
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(3.0, :y)
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```
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"""
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function findmax end
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findmax(f,x) = _find_extreme(f,>,x)
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findmax(x) = findmax(identity,x)
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"""
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NaNMath.argmin(f, domain) -> x
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##### Args:
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* `f`: A function applied to the elements of `domain`;
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defaults to `identity` when `domain` is the only argument.
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* `domain`: A non-empty collection of floating point numbers such that
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`f` is defined on elements of `domain`.
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##### Returns:
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* Returns a value `x` in `domain`, ignoring NaN's, for which `f(x)` is minimized.
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If there are multiple minimal values for `f(x)`, then the first one will be returned.
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If `domain` is a `NamedTuple` or dictionary-like `AbstractDict` L,
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the function is applied to its values. The returned value is `L[k]` for some key `k`
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such that `f(L[k])` is minimal.
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##### Examples:
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```julia
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julia> NaNMath.argmin(abs, [1., -1., -2., 2., NaN])
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1.0
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julia> NaNMath.argmin(identity, [7, 1, 1, NaN])
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1.0
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```
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julia> NaNMath.argmin(exp,Dict("x" => 1.0, "y" => -1.2, "z" => NaN))
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-1.2
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───────────────────────────────────────────────────────────
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NaNMath.argmin(itr) -> key
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##### Args:
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* `itr`: A non-empty iterable of floating point numbers.
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##### Returns:
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* Returns the index or key of the minimal element in `itr`, ignoring NaN's.
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If there are multiple minimal elements, then the first one will be returned.
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If `itr` is a `NamedTuple` or dictionary-like `AbstractDict` L, the returned index is a key `k`,
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such that `f(L[k])` is minimal.
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##### Examples:
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```julia
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julia> NaNMath.argmin([7, 1, 1, NaN])
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2
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julia> NaNMath.argmin([1.0 2; 3 NaN])
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CartesianIndex(1, 1)
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julia> NaNMath.argmin(Dict("x" => 1.0, "y" => -1.2, "z" => NaN))
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"y"
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```
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"""
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function argmin end
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argmin(f,x) = getindex(x,findmin(f,x)[2])
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argmin(x) = findmin(identity,x)[2]
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"""
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NaNMath.argmax(f, domain) -> x
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##### Args:
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* `f`: A function applied to the elements of `domain`;
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defaults to `identity` when `domain` is the only argument.
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* `domain`: A non-empty collection of floating point numbers such that
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`f` is defined on elements of `domain`.
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##### Returns:
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* Returns a value `x` in `domain`, ignoring NaN's, for which `f(x)` is maximized.
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If there are multiple maximal values for `f(x)`, then the first one will be returned.
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If `domain` is a `NamedTuple` or dictionary-like `AbstractDict` L,
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the function is applied to its values. The returned value is `L[k]` for some key `k`
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such that `f(L[k])` is maximal.
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##### Examples:
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```julia
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julia> NaNMath.argmax(abs, [1., -1., -2., NaN])
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-2.0
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julia> NaNMath.argmax(identity, [7, 1, 1, NaN])
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7.0
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```
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───────────────────────────────────────────────────────────
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NaNMath.argmax(itr) -> key
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##### Args:
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* `itr`: A non-empty iterable of floating point numbers.
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##### Returns:
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* Returns the index or key of the maximal element in `itr`, ignoring NaN's.
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If there are multiple maximal elements, then the first one will be returned.
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If `itr` is a `NamedTuple` or dictionary-like `AbstractDict` L, the returned index is a key `k`,
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such that `f(L[k])` is maximal.
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##### Examples:
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```julia
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julia> NaNMath.argmax([7, 1, 1, NaN])
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1
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julia> NaNMath.argmax([1.0 2; 3 NaN])
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CartesianIndex(2, 1)
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julia> NaNMath.argmax(Dict("x" => 1.0, "y" => -1.2, "z" => NaN))
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"x"
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```
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"""
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function argmax end
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argmax(x) = findmax(identity,x)[2]
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argmax(f,x) = getindex(x,findmax(f,x)[2])
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end

‎test/runtests.jl‎

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@@ -70,3 +70,136 @@ using Test
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@test isnan(NaNMath.max(NaN, NaN))
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@test isnan(NaNMath.max(NaN))
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@test NaNMath.max(NaN, NaN, 0.0, 1.0) == 1.0
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## Based on https://github.com/sethaxen/NaNMath.jl/blob/41b3e7edd9dd4cb6c2873abf6e0d90acf43138ec/test/runtests.jl
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@testset "findmin/findmax" begin
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if VERSION ≥ v"1.7"
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xvals = [
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[1., 2., 3., 3., 1.],
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(1., 2., 3., 3., .1),
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(1f0, 2f0, 3f0, -1f0),
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(x=1.0, y=3f0, z=-4.0, w=-2f0),
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Dict(:a => 1.0, :b => 1.0, :d => 3.0, :c => 2.0),
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]
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@testset for x in xvals
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@test NaNMath.findmin(x) === findmin(x)
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@test NaNMath.findmax(x) === findmax(x)
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@test NaNMath.findmin(identity, x) === findmin(identity, x)
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@test NaNMath.findmax(identity, x) === findmax(identity, x)
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@test NaNMath.findmin(sin, x) === findmin(sin, x)
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@test NaNMath.findmax(sin, x) === findmax(sin, x)
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end
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end
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x = [7, 7, NaN, 1, 1, NaN]
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@test NaNMath.findmin(x) === (1.0, 4)
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@test NaNMath.findmax(x) === (7.0, 1)
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@test NaNMath.findmin(identity, x) === (1.0, 4)
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@test NaNMath.findmax(identity, x) === (7.0, 1)
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@test NaNMath.findmin(-, x) === (-7.0, 1)
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@test NaNMath.findmax(-, x) === (-1.0, 4)
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x = [NaN, NaN]
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@test NaNMath.findmin(x) === (NaN, 1)
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@test NaNMath.findmax(x) === (NaN, 1)
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@test NaNMath.findmin(identity, x) === (NaN, 1)
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@test NaNMath.findmax(identity, x) === (NaN, 1)
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@test NaNMath.findmin(sin, x) === (NaN, 1)
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@test NaNMath.findmax(sin, x) === (NaN, 1)
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x = Dict(:a => 1.0, :b => 1 + 2im, :d => 3.0, :c => 2.0)
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@test_throws ErrorException NaNMath.findmin(x)
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@test_throws ErrorException NaNMath.findmax(x)
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x = [3, missing, NaN, -1]
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@test_throws ErrorException NaNMath.findmin(x)
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x = Dict('a' => 1.0, missing => NaN, 'c' => 2.0)
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@test NaNMath.findmin(x) === (1.0, 'a')
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@test NaNMath.findmax(x) === (2.0, 'c')
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x = Dict(:x => 3.0, :w => 2f0, :y => -1.0, :z => NaN)
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@test NaNMath.findmin(x) === (-1.0, :y)
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@test NaNMath.findmax(x) === (3.0, :x)
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@test NaNMath.findmin(identity, x) === (-1.0, :y)
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@test NaNMath.findmax(identity, x) === (3.0, :x)
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@test NaNMath.findmin(-, x) === (-3.0, :x)
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@test NaNMath.findmax(-, x) === (1.0, :y)
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@test NaNMath.findmin(exp, x) === (exp(-1.0), :y)
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@test NaNMath.findmax(exp, x) === (exp(3.0), :x)
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x = (x=1.0, y=NaN, z=NaN, w=-2.0)
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@test NaNMath.findmin(x) === (-2.0, :w)
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@test NaNMath.findmax(x) === (1.0, :x)
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@test NaNMath.findmin(-,x) === (-1.0, :x)
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@test NaNMath.findmax(-,x) === (2.0, :w)
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x = [2.0 3.0; 2.0 -1.0]
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@test NaNMath.findmin(x) === (-1.0, CartesianIndex(2, 2))
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@test NaNMath.findmax(x) === (3.0, CartesianIndex(1, 2))
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@test NaNMath.findmin(exp,x) === (exp(-1), CartesianIndex(2, 2))
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@test NaNMath.findmax(exp,x) === (exp(3.0), CartesianIndex(1, 2))
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end
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@testset "argmin/argmax" begin
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if VERSION ≥ v"1.7"
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xvals = [
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[1., 2., 4., 3., 1.],
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(1., 2., 4., 3., .1),
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(1f0, 2f0, 3f0, -1f0),
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(x=1.0, y=3f0, z=-4.0, w=-2f0),
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Dict(:a => 1.0, :b => 1.0, :d => 3.0, :c => 2.0),
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]
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@testset for x in xvals
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@test NaNMath.argmin(x) === argmin(x)
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@test NaNMath.argmax(x) === argmax(x)
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x isa Dict || @test NaNMath.argmin(identity, x) === argmin(identity, x)
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x isa Dict || @test NaNMath.argmax(identity, x) === argmax(identity, x)
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x isa Dict || @test NaNMath.argmin(sin, x) === argmin(sin, x)
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x isa Dict || @test NaNMath.argmax(sin, x) === argmax(sin, x)
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end
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end
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x = [7, 7, NaN, 1, 1, NaN]
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@test NaNMath.argmin(x) === 4
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@test NaNMath.argmax(x) === 1
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@test NaNMath.argmin(identity, x) === 1.0
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@test NaNMath.argmax(identity, x) === 7.0
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@test NaNMath.argmin(-, x) === 7.0
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@test NaNMath.argmax(-, x) === 1.0
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x = [NaN, NaN]
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@test NaNMath.argmin(x) === 1
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@test NaNMath.argmax(x) === 1
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@test NaNMath.argmin(identity, x) === NaN
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@test NaNMath.argmax(identity, x) === NaN
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@test NaNMath.argmin(-, x) === NaN
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@test NaNMath.argmax(-, x) === NaN
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x = [3, missing, NaN, -1]
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@test_throws ErrorException NaNMath.argmin(x)
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@test_throws ErrorException NaNMath.argmax(x)
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x = Dict('a' => 1.0, missing => NaN, 'c' => 2.0)
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@test NaNMath.argmin(x) === 'a'
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@test NaNMath.argmax(x) === 'c'
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x = Dict(:v => NaN, :w => 2.1f0, :x => 3.1, :z => -1.0, :y => NaN)
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@test NaNMath.argmin(x) === :z
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@test NaNMath.argmax(x) === :x
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@test NaNMath.argmin(-, x) === 3.1
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@test NaNMath.argmax(-, x) === -1.0
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@test NaNMath.argmin(exp, x) === -1.0
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@test NaNMath.argmax(exp, x) === 3.1
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x = (x=1.1, y=NaN, z=NaN, w=-2.3)
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@test NaNMath.argmin(x) === :w
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@test NaNMath.argmax(x) === :x
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@test NaNMath.argmin(exp, x) === -2.3
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@test NaNMath.argmax(exp, x) === 1.1
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x = [2.0 3.0; 2.0 -1.0]
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@test NaNMath.argmin(x) === CartesianIndex(2, 2)
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@test NaNMath.argmax(x) === CartesianIndex(1, 2)
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@test NaNMath.argmin(exp,x) === -1.0
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@test NaNMath.argmax(exp,x) === 3.0
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end

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