Shifted interval calculation back into recipe file

Author: hotplot

src/PlotRecipes.jl

@@ -1,6 +1,22 @@
 using RecipesBase
 
-@recipe function poly_recipe(p::Poly, xs = polyinterval(p))
+function poly_interval(p::Poly)
+    # Find points of interest
+    zero_pts = roots(p)
+    crit_pts = roots(polyder(p, 1))
+    infl_pts = roots(polyder(p, 2))
+    pts = sort([ real(pt) for pt in [zero_pts; crit_pts; infl_pts] if isreal(pt) ])
+
+    # Choose a range that shows all interesting points with some margin
+    min_x, max_x = length(pts) > 0 ? (pts[1], pts[end]) : (-1, 1)
+    diff = max(max_x - min_x, 1)
+    a = min_x - diff
+    b = max_x + diff
+
+    return a : diff/100 : b
+end
+
+@recipe function poly_recipe(p::Poly, xs = poly_interval(p))
     buff = IOBuffer()
     printpoly(buff, p)
     label --> String(take!(buff))

src/Polynomials.jl

@@ -5,7 +5,7 @@ module Polynomials
 
 export Poly, poly
 export degree, coeffs, variable, printpoly
-export polyval, polyint, polyder, roots, polyfit, polyinterval
+export polyval, polyint, polyder, roots, polyfit
 export Pade, padeval
 
 import Base: length, size, eltype, collect, eachindex, lastindex
@@ -717,40 +717,6 @@ end
 polyfit(x,y,sym::Symbol) = polyfit(x,y,length(x)-1, sym)
 
 
-"""
-    polyinterval(p)
-
-Choose a sensible interval containing points of interest for the polynomial `p`.
-
-The interval contains some margin either side to allow for plotting.
-
-# Examples
-
-```julia-repl
-julia> polyinterval(Poly([0, 0, 1])) # contains single critical point at x=0
--1.0:0.01:1.0
-
-julia> polyinterval(Poly([1, 0, 3, -1])) # points of interest between 0 and 3.1
--3.103803402735535:0.031038034027355346:6.20760680547107
-```
-"""
-function polyinterval(p :: Poly)
-    # Find points of interest
-    zero_pts = roots(p)
-    crit_pts = roots(polyder(p, 1))
-    infl_pts = roots(polyder(p, 2))
-    pts = sort([ real(pt) for pt in [zero_pts; crit_pts; infl_pts] if isreal(pt) ])
-
-    # Choose a range that shows all interesting points with some margin
-    min_x, max_x = length(pts) > 0 ? (pts[1], pts[end]) : (-1, 1)
-    diff = max(max_x - min_x, 1)
-    a = min_x - diff
-    b = max_x + diff
-
-    return a : diff/100 : b
-end
-
-
 ### Pull in others
 include("pade.jl")
 include("PlotRecipes.jl")