From f7817a79aed7fd472ab2ed1584be4a2faa645a43 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89milie=20Feral?= <emilie.feral@numworks.com>
Date: Wed, 14 Jun 2017 12:20:31 +0200
Subject: [PATCH] [poincare] Handle real fractions apart from complex fractions

Change-Id: I0caa905c8ddc4a85db31a0dc5e5bc4ffd49c31c4
---
 poincare/src/fraction.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/poincare/src/fraction.cpp b/poincare/src/fraction.cpp
index 3f1f569b6..ed2bb0912 100644
--- a/poincare/src/fraction.cpp
+++ b/poincare/src/fraction.cpp
@@ -34,6 +34,13 @@ Expression::Type Fraction::type() const {
 
 Expression * Fraction::evaluateOnComplex(Complex * c, Complex * d, Context& context, AngleUnit angleUnit) const {
   float norm = d->a()*d->a() + d->b()*d->b();
+  /* We handle the case of c and d pure real numbers apart. Even if the complex
+   * fraction is mathematically correct on real numbers, it requires more
+   * operations and is thus more likely to propagate errors due to float exact
+   * representation. */
+  if (d->b() == 0.0f && c->b() == 0.0f) {
+    return new Complex(Complex::Float(c->a()/d->a()));
+  }
   return new Complex(Complex::Cartesian((c->a()*d->a()+c->b()*d->b())/norm, (d->a()*c->b()-c->a()*d->b())/norm));
 }