Working n-dimensional setdiff

JuliaIntervals · May 29, 2016 · ab8cce9 · ab8cce9
1 parent bd9ae2f
commit ab8cce9
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diff --git a/src/multidim/setdiff.jl b/src/multidim/setdiff.jl
@@ -19,16 +19,6 @@ function labelled_setdiff{T}(x::Interval{T}, y::Interval{T})
 
 end
 
-# doc"""
-#     setdiff(A::IntervalBox{N,T}, B::IntervalBox{N,T})
-#
-# Returns a vector of `IntervalBox`es that are in the set difference `A \ B`,
-# i.e. the set of `x` that are in `A` but not in `B`.
-#
-# Algorithm: Iterate x direction, looking for the sub-interval in that direction
-# that is non-trivial, i.e. that has an overlap. For that one, iterate down a "level"
-# to the next variable and repeat.
-# """
 # function setdiff{N,T}(A::IntervalBox{N,T}, B::IntervalBox{N,T})
 #     X = [labelled_setdiff(a,b) for (a, b) in zip(A, B)]
 #     lengths = map(length, X)
@@ -43,26 +33,30 @@ end
 #
 #     end
 # end
+doc"""
+    setdiff(A::IntervalBox{N,T}, B::IntervalBox{N,T})
+
+Returns a vector of `IntervalBox`es that are in the set difference `A \ B`,
+i.e. the set of `x` that are in `A` but not in `B`.
+
+Algorithm: Start from the total overlap (in all directions);
+expand each direction in turn.
+"""
 function setdiff{N,T}(A::IntervalBox{N,T}, B::IntervalBox{N,T})
     X = [labelled_setdiff(a,b) for (a, b) in zip(A, B)]
     # ordered such that the first in each is the excluded interval
 
     first = [ i[1] for i in X ]
     labels = [i[2] for i in first]
 
-    any(labels .== -1) && return A  # no overlap
+    any(labels .== -1) && return [A]  # no overlap
 
-    @assert all(labels .== 1)
+    # @assert all(labels .== 1)
 
     excluded = [i[1] for i in first]
 
     result_list = IntervalBox{N,T}[]
 
-    @show first
-    @show labels
-    @show excluded
-
-
     for dimension in N:-1:1
         for which in X[dimension][2:end]
             excluded[dimension] = which[1]

diff --git a/test/multidim_tests/multidim.jl b/test/multidim_tests/multidim.jl
@@ -35,6 +35,54 @@ facts("@intervalbox tests") do
 
     @intervalbox g(x, y) = x - y
     @fact isa(g(X), IntervalBox) --> true
+end
+
+facts("setdiff for IntervalBox") do
+    X = IntervalBox(2..4, 3..5)
+    Y = IntervalBox(3..5, 4..6)
+    @fact setdiff(X, Y) --> [ IntervalBox(3..4, 3..4),
+                              IntervalBox(2..3, 3..5) ]
+
+
+    X = IntervalBox(2..5, 3..6)
+    Y = IntervalBox(-10..10, 4..5)
+    @fact setdiff(X, Y) --> [ IntervalBox(2..5, 3..4),
+                              IntervalBox(2..5, 5..6) ]
+
+
+    X = IntervalBox(2..5, 3..6)
+    Y = IntervalBox(4..6, 4..5)
+    @fact setdiff(X, Y) --> [ IntervalBox(4..5, 3..4),
+                              IntervalBox(4..5, 5..6),
+                              IntervalBox(2..4, 3..6) ]
+
+
+    X = IntervalBox(2..5, 3..6)
+    Y = IntervalBox(3..4, 4..5)
+    @fact setdiff(X, Y) --> [ IntervalBox(3..4, 3..4),
+                              IntervalBox(3..4, 5..6),
+                              IntervalBox(2..3, 3..6),
+                              IntervalBox(4..5, 3..6) ]
+
+
+    X = IntervalBox(2..5, 3..6)
+    Y = IntervalBox(2..4, 10..20)
+    @fact setdiff(X, Y) --> typeof(X)[X]
+
+
+    X = IntervalBox(2..5, 3..6)
+    Y = IntervalBox(-10..10, -10..10)
+    @fact setdiff(X, Y) --> typeof(X)[]
+
+
+    X = IntervalBox(1..4, 3..6, 7..10)
+    Y = IntervalBox(2..3, 4..5, 8..9)
+    @fact setdiff(X, Y) --> [ IntervalBox(2..3, 4..5, 7..8),
+                              IntervalBox(2..3, 4..5, 9..10),
+                              IntervalBox(2..3, 3..4, 7..10),
+                              IntervalBox(2..3, 5..6, 7..10),
+                              IntervalBox(1..2, 3..6, 7..10),
+                              IntervalBox(3..4, 3..6, 7..10) ]
 
 
 end