clean up mess; close issue #373 (#374)

* clean up mess; close issue #373

* doctest

Project.toml

@@ -1,6 +1,6 @@
 name = "Roots"
 uuid = "f2b01f46-fcfa-551c-844a-d8ac1e96c665"
-version = "2.0.13"
+version = "2.0.14"
 
 [deps]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"

src/Bracketing/alefeld_potra_shi.jl

@@ -186,7 +186,7 @@ function calculateΔ(::A2425{K}, F::Callable_Function, c₀::T, ps) where {K,T}
         a, b, d, fa, fb, fd = bracket(a, b, c, fa, fb, fc)
 
         iszero(fc) && break
-        if (isnan(fc) || isfinite(c))
+        if (isnan(fc) || !isfinite(c))
             c = c₀
             break
         end
@@ -244,7 +244,7 @@ function calculateΔ(::A57{K}, F::Callable_Function, c₀::T, ps) where {K,T}
         a, b, d, fa, fb, fd = bracket(a, b, c, fa, fb, fc)
 
         iszero(fc) && break # fa or fb is 0
-        if (!isfinite(fc) || isfinite(c))
+        if (!isfinite(fc) || !isfinite(c))
             c = c₀
             break
         end
@@ -328,7 +328,7 @@ function newton_quadratic(a, b, d, fa, fb, fd, k::Int)
     A = f_abd(a, b, d, fa, fb, fd)
     B = f_ab(a, b, fa, fb)
 
-    (iszero(A) || isfinite(A)) && return a - fa / B
+    (iszero(A) || !isfinite(A)) && return a - fa / B
 
     r = sign(A) * sign(fa) > 0 ? a : b
 

src/trace.jl

@@ -91,11 +91,10 @@ julia> find_zero(sin, (3, 4), Roots.A42(), tracks=tracker) ≈ π
 true
 
 julia> get(tracker)
-5-element Vector{NamedTuple{names, Tuple{Float64, Float64}} where names}:
+4-element Vector{NamedTuple{names, Tuple{Float64, Float64}} where names}:
  (a = 3.0, b = 4.0)
  (a = 3.0, b = 3.157162792479947)
- (a = 3.14154625558915, b = 3.1416390553287794)
- (a = 3.1415926535730327, b = 3.141592653606554)
+ (a = 3.141592614491745, b = 3.1415926926910007)
  (a = 3.141592653589793, b = 3.141592653589794)
 
 julia> last(tracker)

test/test_bracketing.jl

@@ -423,4 +423,11 @@ end
 
     # last bit of accuracy, when close issue #368
     @test find_zero(x -> sinpi(-1/40 + x / 40) + 1 - x, (0,2), A42()) == 1.0
+
+    # sloppy bug using isfinite (#373)
+    f = x -> 1 - x / (x - 1)^2
+    xleft = 1 + eps(BigFloat)
+    xright = 3 * xleft
+    x =find_zero(f, (xleft, xright))
+    @test abs(f(x)) <= 2eps(BigFloat)
 end