From 5d8abefdc2dcf6487643ece3a87cc5d48b14cafd Mon Sep 17 00:00:00 2001
From: Olivier Cots <olivier.cots@irit.fr>
Date: Mon, 10 Jun 2024 19:24:22 +0200
Subject: [PATCH 1/2] fix plot constant negative value

---
 src/plot.jl              |  2 +-
 test/test_plot_joseph.jl | 53 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)
 create mode 100644 test/test_plot_joseph.jl

diff --git a/src/plot.jl b/src/plot.jl
index 5f6295a1..7261faae 100644
--- a/src/plot.jl
+++ b/src/plot.jl
@@ -63,7 +63,7 @@ function __plot_time!(p::Union{Plots.Plot, Plots.Subplot}, sol::OptimalControlSo
 
     if (ymin != Inf) && (ymax != -Inf) && (abs(ymax-ymin) ≤ abs(ymin)*tol)
         ymiddle = (ymin+ymax)/2.0
-        ylims!(p, (0.9*ymiddle, 1.1*ymiddle))
+        ymiddle > 0 ? ylims!(p, (0.9*ymiddle, 1.1*ymiddle)) : ylims!(p, (1.1*ymiddle, 0.9*ymiddle))
     end
 
     return p
diff --git a/test/test_plot_joseph.jl b/test/test_plot_joseph.jl
new file mode 100644
index 00000000..29540eaa
--- /dev/null
+++ b/test/test_plot_joseph.jl
@@ -0,0 +1,53 @@
+# using OptimalControl
+
+# @def ocp begin
+
+#     t ∈ [ 0, 1 ], time
+#     x ∈ R, state
+#     u ∈ R, control
+#     x(0) == 0
+#     -1 ≤ u(t) ≤ 1
+#     ẋ(t) == -x(t) + u(t)
+#     x(1) → min
+
+# end
+
+# sol = solve(ocp, grid_size=20, print_level=5)
+# plt = plot(sol)
+
+# a la main
+using CTBase
+
+n=1
+m=1
+t0=0
+tf=1
+x0=0
+x = t -> -1+1e-8*rand()
+p = t -> +1+1e-8*rand()
+u = t -> -1
+objective = 1
+#
+N=201
+times = range(t0, tf, N)
+#
+
+sol = OptimalControlSolution()
+sol.state_dimension = n
+sol.control_dimension = m
+sol.times = times
+sol.time_name="t"
+sol.state = x
+sol.state_name = "x"
+sol.state_components_names = [ "x" ]
+sol.costate = p
+sol.control = u
+sol.control_name = "u"
+sol.control_components_names = [ "u" ]
+sol.objective = objective
+sol.iterations = 0
+sol.stopping = :dummy
+sol.message = "ceci est un test"
+sol.success = true
+
+plt = plot(sol)
\ No newline at end of file

From f8773468cfb6f0a7018f39417495ce9295fe244b Mon Sep 17 00:00:00 2001
From: Olivier Cots <olivier.cots@irit.fr>
Date: Mon, 10 Jun 2024 19:40:22 +0200
Subject: [PATCH 2/2] fix plot constant negative value

---
 src/plot.jl              | 6 +++++-
 test/test_plot_joseph.jl | 4 ++--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/plot.jl b/src/plot.jl
index 7261faae..8dc17dbe 100644
--- a/src/plot.jl
+++ b/src/plot.jl
@@ -63,7 +63,11 @@ function __plot_time!(p::Union{Plots.Plot, Plots.Subplot}, sol::OptimalControlSo
 
     if (ymin != Inf) && (ymax != -Inf) && (abs(ymax-ymin) ≤ abs(ymin)*tol)
         ymiddle = (ymin+ymax)/2.0
-        ymiddle > 0 ? ylims!(p, (0.9*ymiddle, 1.1*ymiddle)) : ylims!(p, (1.1*ymiddle, 0.9*ymiddle))
+        if (abs(ymiddle) < 1e-12)
+            ylims!(p, (-0.1, 0.1))
+        else
+            ymiddle > 0 ? ylims!(p, (0.9*ymiddle, 1.1*ymiddle)) : ylims!(p, (1.1*ymiddle, 0.9*ymiddle))
+        end
     end
 
     return p
diff --git a/test/test_plot_joseph.jl b/test/test_plot_joseph.jl
index 29540eaa..fcb5c708 100644
--- a/test/test_plot_joseph.jl
+++ b/test/test_plot_joseph.jl
@@ -24,8 +24,8 @@ t0=0
 tf=1
 x0=0
 x = t -> -1+1e-8*rand()
-p = t -> +1+1e-8*rand()
-u = t -> -1
+p = t -> 0+1e-8*rand()
+u = t -> 0
 objective = 1
 #
 N=201