Merge pull request #46 from PumasAI/an/zerospline

Fix dir=:left in ZeroSpline
SciML · Sep 20, 2019 · 543a7ed · 543a7ed
2 parents e4aa09f + 3027fb5
commit 543a7ed
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Showing 3 changed files with 50 additions and 14 deletions.
diff --git a/src/caches/interpolation_caches.jl b/src/caches/interpolation_caches.jl
@@ -45,7 +45,7 @@ end
 struct ZeroSpline{uType,tType,dirType,FT,T} <: AbstractInterpolation{FT,T}
   u::uType
   t::tType
-  dir::Symbol
+  dir::Symbol # indicates if value to the $dir should be used for the interpolation
   ZeroSpline{FT}(u,t,dir) where FT = new{typeof(u),typeof(t),typeof(dir),FT,eltype(u)}(u,t,dir)
 end
 

diff --git a/src/interpolation_alg/interpolation_methods.jl b/src/interpolation_alg/interpolation_methods.jl
@@ -87,18 +87,24 @@ end
 
 # ZeroSpline Interpolation
 function (A::ZeroSpline{<:AbstractVector{<:Number}})(t::Number)
-  i = searchsortedfirst(A.t, t)
   if A.dir === :left
-    return A.u[max(2, i) - 1]
+    # :left means that value to the left is used for interpolation
+    i = searchsortedlast(A.t, t)
+    return A.u[max(1, i)]
   else
+    # :right means that value to the right is used for interpolation
+    i = searchsortedfirst(A.t, t)
     return A.u[min(length(A.t), i)]
   end
 end
  function (A::ZeroSpline{<:AbstractMatrix{<:Number}})(t::Number)
-  i = searchsortedfirst(A.t, t)
   if A.dir === :left
-    return A.u[:, max(2, i) - 1]
+    # :left means that value to the left is used for interpolation
+    i = searchsortedlast(A.t, t)
+    return A.u[:, max(1, i)]
   else
+    # :right means that value to the right is used for interpolation
+    i = searchsortedfirst(A.t, t)
     return A.u[:, min(length(A.t), i)]
   end
 end

diff --git a/test/interpolation_tests.jl b/test/interpolation_tests.jl
@@ -60,22 +60,52 @@ A = LagrangeInterpolation(u,t)
 
 
 # ZeroSpline Interpolation
-u = [1.0, 4.0, 9.0, 16.0]
+u = [1.0, 2.0, 0.0, 1.0]
 t = [1.0, 2.0, 3.0, 4.0]
-A = ZeroSpline(u,t)
-
+A = ZeroSpline(u, t, dir=:right)
+@test A(0.5) == 1.0
+@test A(1.0) == 1.0
+@test A(1.5) == 2.0
+@test A(2.0) == 2.0
+@test A(2.5) == 0.0
+@test A(3.0) == 0.0
+@test A(3.5) == 1.0
+@test A(4.0) == 1.0
+@test A(4.5) == 1.0
+A = ZeroSpline(u, t) # dir=:left is default
+@test A(0.5) == 1.0
 @test A(1.0) == 1.0
 @test A(1.5) == 1.0
-@test A(2.5) == 4.0
-@test A(4.0) == 9.0
-
-u = [1.0 4.0 9.0 16.0; 1.0 4.0 9.0 16.0]
+@test A(2.0) == 2.0
+@test A(2.5) == 2.0
+@test A(3.0) == 0.0
+@test A(3.5) == 0.0
+@test A(4.0) == 1.0
+@test A(4.5) == 1.0
+
+u = [1.0 2.0 0.0 1.0; 1.0 2.0 0.0 1.0]
 A = ZeroSpline(u,t)
 
+A = ZeroSpline(u, t, dir=:right)
+@test A(0.5) == [1.0, 1.0]
+@test A(1.0) == [1.0, 1.0]
+@test A(1.5) == [2.0, 2.0]
+@test A(2.0) == [2.0, 2.0]
+@test A(2.5) == [0.0, 0.0]
+@test A(3.0) == [0.0, 0.0]
+@test A(3.5) == [1.0, 1.0]
+@test A(4.0) == [1.0, 1.0]
+@test A(4.5) == [1.0, 1.0]
+A = ZeroSpline(u, t) # dir=:left is default
+@test A(0.5) == [1.0, 1.0]
 @test A(1.0) == [1.0, 1.0]
 @test A(1.5) == [1.0, 1.0]
-@test A(2.5) == [4.0, 4.0]
-@test A(4.0) == [9.0, 9.0]
+@test A(2.0) == [2.0, 2.0]
+@test A(2.5) == [2.0, 2.0]
+@test A(3.0) == [0.0, 0.0]
+@test A(3.5) == [0.0, 0.0]
+@test A(4.0) == [1.0, 1.0]
+@test A(4.5) == [1.0, 1.0]
 
 # QuadraticSpline Interpolation
 u = [0.0, 1.0, 3.0]