From 448e803f78cfc0b4f2a873e960d5527d0082ea7c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89milie=20Feral?= <emilie.feral@numworks.com>
Date: Wed, 19 Apr 2017 18:48:11 +0200
Subject: [PATCH] [poincare] Ensure that a float power an integer in a real

Change-Id: I19416271f127ac487f61191cacc6243bb4e0c160
---
 poincare/src/power.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/poincare/src/power.cpp b/poincare/src/power.cpp
index f94c6796d..c303a50aa 100644
--- a/poincare/src/power.cpp
+++ b/poincare/src/power.cpp
@@ -47,6 +47,13 @@ Expression * Power::evaluateOnComplex(Complex * c, Complex * d, Context& context
   }
   /* Third case only c is complex */
   float radius = powf(c->r(), d->a());
+  if (c->b() == 0 && d->a() == roundf(d->a())) {
+    /* We handle the case -c float and d integer- separatly to avoid getting
+     * complex result due to float representation: a float power an integer is
+     * always real. */
+    return new Complex(Complex::Cartesian(radius, 0.0f));
+  }
+  /* Third case only c is complex */
   float theta = d->a()*c->th();
   return new Complex(Complex::Polar(radius, theta));
 }