Merge pull request #165 from hotplot/plotrecipes

Added plot recipe

Author: jverzani

REQUIRE

@@ -1 +1,2 @@
 julia 0.7
+RecipesBase

src/PlotRecipes.jl

@@ -0,0 +1,40 @@
+using RecipesBase
+
+
+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/2
+    b = max_x + diff/2
+
+    return a : diff/50 : b
+end
+
+
+function poly_label(p::Poly)
+    buff = IOBuffer()
+    printpoly(buff, p)
+    String(take!(buff))
+end
+
+
+@recipe function poly_recipe(p::Poly, range = poly_interval(p))
+    label --> poly_label(p)
+    range, map(x -> polyval(p, x), range)
+end
+
+
+@recipe function poly_recipe(p::Poly, a, b)
+    label --> poly_label(p)
+    step = (b-a)/100
+    xs = a:step:b
+    ys = map(x -> polyval(p, x), xs)
+    xs, ys
+end

src/Polynomials.jl

@@ -716,7 +716,9 @@ function polyfit(x, y, n::Int=length(x)-1, sym::Symbol=:x)
 end
 polyfit(x,y,sym::Symbol) = polyfit(x,y,length(x)-1, sym)
 
+
 ### Pull in others
 include("pade.jl")
+include("PlotRecipes.jl")
 
 end # module Poly

test/REQUIRE

@@ -1 +1 @@
-SpecialFunctions
+SpecialFunctions