Use FindFirstFunctions.jl

Project.toml

@@ -3,6 +3,7 @@ uuid = "82cc6244-b520-54b8-b5a6-8a565e85f1d0"
 version = "4.7.0"
 
 [deps]
+FindFirstFunctions = "64ca27bc-2ba2-4a57-88aa-44e436879224"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 PrettyTables = "08abe8d2-0d0c-5749-adfa-8a2ac140af0d"
 RecipesBase = "3cdcf5f2-1ef4-517c-9805-6587b60abb01"
@@ -24,6 +25,7 @@ DataInterpolationsSymbolicsExt = "Symbolics"
 [compat]
 Aqua = "0.8"
 ChainRulesCore = "1"
+FindFirstFunctions = "1"
 FiniteDifferences = "0.12.31"
 ForwardDiff = "0.10.19"
 LinearAlgebra = "1.10"

docs/src/manual.md

@@ -11,9 +11,3 @@ CubicSpline
 BSplineInterpolation
 BSplineApprox
 ```
-
-# Utility Functions
-
-```@docs
-DataInterpolations.bracketstrictlymontonic
-```

src/DataInterpolations.jl

@@ -17,6 +17,8 @@ end
 
 using LinearAlgebra, RecipesBase
 using PrettyTables
+import FindFirstFunctions: searchsortedfirstcorrelated, searchsortedlastcorrelated,
+                           bracketstrictlymontonic
 
 include("interpolation_caches.jl")
 include("interpolation_utils.jl")

src/interpolation_utils.jl

@@ -62,69 +62,3 @@ function munge_data(U::StridedMatrix, t::AbstractVector)
 
     return hcat(newUs...), newt
 end
-
-"""
-    bracketstrictlymontonic(v, x, guess; lt=<comparison>, by=<transform>, rev=false)
-
-Starting from an initial `guess` index, find indices `(lo, hi)` such that `v[lo] ≤ x ≤ v[hi]`
-according to the specified order, assuming that `x` is actually within the range of
-values found in `v`.  If `x` is outside that range, either `lo` will be `firstindex(v)` or
-`hi` will be `lastindex(v)`.
-
-Note that the results will not typically satisfy `lo ≤ guess ≤ hi`.  If `x` is precisely
-equal to a value that is not unique in the input `v`, there is no guarantee that `(lo, hi)`
-will encompass *all* indices corresponding to that value.
-
-This algorithm is essentially an expanding binary search, which can be used as a precursor
-to `searchsorted` and related functions, which can take `lo` and `hi` as arguments.  The
-purpose of using this function first would be to accelerate convergence in those functions
-by using correlated `guess`es for repeated calls.  The best `guess` for the next call of
-this function would be the index returned by the previous call to `searchsorted`.
-
-See `sort!` for an explanation of the keyword arguments `by`, `lt` and `rev`.
-"""
-function bracketstrictlymontonic(v::AbstractVector,
-        x,
-        guess::T,
-        o::Base.Order.Ordering)::NTuple{2, keytype(v)} where {T <: Integer}
-    bottom = firstindex(v)
-    top = lastindex(v)
-    if guess < bottom || guess > top
-        return bottom, top
-        # # NOTE: for cache efficiency in repeated calls, we avoid accessing the first and last elements of `v`
-        # # on each call to this function.  This should only result in significant slow downs for calls with
-        # # out-of-bounds values of `x` *and* bad `guess`es.
-        # elseif lt(o, x, v[bottom])
-        #     return bottom, bottom
-        # elseif lt(o, v[top], x)
-        #     return top, top
-    else
-        u = T(1)
-        lo, hi = guess, min(guess + u, top)
-        @inbounds if Base.Order.lt(o, x, v[lo])
-            while lo > bottom && Base.Order.lt(o, x, v[lo])
-                lo, hi = max(bottom, lo - u), lo
-                u += u
-            end
-        else
-            while hi < top && !Base.Order.lt(o, x, v[hi])
-                lo, hi = hi, min(top, hi + u)
-                u += u
-            end
-        end
-    end
-    return lo, hi
-end
-
-function searchsortedfirstcorrelated(v::AbstractVector, x, guess)
-    lo, hi = bracketstrictlymontonic(v, x, guess, Base.Order.Forward)
-    searchsortedfirst(v, x, lo, hi, Base.Order.Forward)
-end
-
-function searchsortedlastcorrelated(v::AbstractVector, x, guess)
-    lo, hi = bracketstrictlymontonic(v, x, guess, Base.Order.Forward)
-    searchsortedlast(v, x, lo, hi, Base.Order.Forward)
-end
-
-searchsortedfirstcorrelated(r::AbstractRange, x, _) = searchsortedfirst(r, x)
-searchsortedlastcorrelated(r::AbstractRange, x, _) = searchsortedlast(r, x)