Add spread()

Project.toml

@@ -7,6 +7,7 @@ version = "0.13.0"
 [deps]
 CSV = "336ed68f-0bac-5ca0-87d4-7b16caf5d00b"
 Colors = "5ae59095-9a9b-59fe-a467-6f913c188581"
+Combinatorics = "861a8166-3701-5b0c-9a16-15d98fcdc6aa"
 DataFrames = "a93c6f00-e57d-5684-b7b6-d8193f3e46c0"
 Distributions = "31c24e10-a181-5473-b8eb-7969acd0382f"
 DocOpt = "968ba79b-81e4-546f-ab3a-2eecfa62a9db"

src/NeRCA.jl

@@ -10,6 +10,7 @@ using KM3io
 
 using StaticArrays
 using Rotations
+using Combinatorics
 using Setfield
 using Colors
 using LandauDistribution
@@ -30,8 +31,7 @@ export
     duhits, nfoldhits,
     most_frequent, categorize, modulemap,
     initdb, streamds, detx,  # db.jl
-    rotator,
-    fibonaccisphere, fibonaccicone,
+    fibonaccisphere, fibonaccicone, rotator, spread,
     # re-export from KM3io
     Detector, Direction, Position
 

src/math.jl

@@ -138,3 +138,15 @@ function rotator(dir::Direction)
 
     RotMatrix(ct*cp, -sp, st*cp, ct*sp, cp, st*sp, -st, 0.0, ct)
 end
+
+"""
+
+Calculates the maximum angle between the given objects which have a direction.
+
+"""
+function spread(objects::Vector{T}) where T
+    angles = map(combinations(objects, 2)) do obj_pair
+        angle(obj_pair...)
+    end
+    maximum(angles)
+end

test/math_tests.jl

@@ -7,4 +7,24 @@ using Test
     @test π/2 ≈ angle([1,0,0], [0,1,0])
     @test π/2 ≈ angle([1,0,0], [0,0,1])
     @test π ≈ angle([1,0,0], [-1,0,0])
+
+end
+
+
+@testset "spread()" begin
+    directions = [
+        Direction(1.0, 0.0, 0.0),
+        Direction(1.0, 0.0, 0.0),
+    ]
+    @test 0 ≈ spread(directions)
+    directions = [
+        Direction(1.0, 0.0, 0.0),
+        Direction(0.0, 1.0, 0.0),
+    ]
+    @test π/2 ≈ spread(directions)
+    directions = [
+        Direction(1.0, 0.0, 0.0),
+        Direction(-1.0, 0.0, 0.0),
+    ]
+    @test π ≈ spread(directions)
 end