From 8f65c3341f4cd328c19f1cb2f3d4545eb8ef7531 Mon Sep 17 00:00:00 2001
From: Samuel GOUGEON <sgougeon@free.fr>
Date: Thu, 7 Jan 2021 22:00:53 +0100
Subject: [PATCH] * Bug 16305 fixed: unwrap() failed unfolding straight
 segments

  http://bugzilla.scilab.org/16305

Change-Id: I8015da57839530a120190869663d6e35d87ed2e9
---
 scilab/CHANGES.md                                  |    1 +
 .../modules/elementary_functions/macros/unwrap.sci |    3 ++-
 .../tests/nonreg_tests/bug_16305.tst               |   23 ++++++++++++++++++++
 3 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 scilab/modules/elementary_functions/tests/nonreg_tests/bug_16305.tst

diff --git a/scilab/CHANGES.md b/scilab/CHANGES.md
index 13e9e30..a8eb7a4 100644
--- a/scilab/CHANGES.md
+++ b/scilab/CHANGES.md
@@ -365,6 +365,7 @@ Bug Fixes
 * [#16274](https://bugzilla.scilab.org/16274): assert_checkequal() did not considered equal matching Nan or void elements in (nested) containers.
 * [#16288](https://bugzilla.scilab.org/16288): An error message from `wavread` was wrong.
 * [#16297](https://bugzilla.scilab.org/16297): After function test(), e={}, endfunction; macr2tree(test)  crashes Scilab.
+* [#16305](https://bugzilla.scilab.org/16305): `unwrap()` failed unfolding curves with straight segments.
 * [#16337](https://bugzilla.scilab.org/16337): The 3rd output of `[U,km,ku] = unique(..)` was not implemented.
 * [#16340](https://bugzilla.scilab.org/16340): `setdiff("","")` produced `""` instead of `[]`. The `"c"` and `"r"` options yielded an error for string inputs. Input arguments were poorly checked.
 * [#16342](https://bugzilla.scilab.org/16342): `strcat()` was much slower in Scilab 6.0.2.
diff --git a/scilab/modules/elementary_functions/macros/unwrap.sci b/scilab/modules/elementary_functions/macros/unwrap.sci
index dea22f0..9faa852 100644
--- a/scilab/modules/elementary_functions/macros/unwrap.sci
+++ b/scilab/modules/elementary_functions/macros/unwrap.sci
@@ -137,7 +137,8 @@ function [retval, K] = unwrap(a, varargin)
     else
         // Local radius of curvature: calculation
         Rc = ((1+d(:,2:$).^2).^1.5) ./ abs(d(:,2:$)-d(:,1:$-1))
-        K = find(Rc < mean(Rc)/30) // criterium to detect cusp points
+        // criterium to detect cusp points:
+        K = find(Rc < min(mean(Rc)/30, min(Rc)/(5e3*%eps))) 
         [nR,nC] = size(Rc)
 
         // trimming edges (due to duplication of 1st & last columns):
diff --git a/scilab/modules/elementary_functions/tests/nonreg_tests/bug_16305.tst b/scilab/modules/elementary_functions/tests/nonreg_tests/bug_16305.tst
new file mode 100644
index 0000000..fd8fdbe
--- /dev/null
+++ b/scilab/modules/elementary_functions/tests/nonreg_tests/bug_16305.tst
@@ -0,0 +1,23 @@
+// =============================================================================
+// Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
+// Copyright (C) 2021 - Samuel GOUGEON
+//
+//  This file is distributed under the same license as the Scilab package.
+// =============================================================================
+//
+// <-- CLI SHELL MODE -->
+// <-- NO CHECK REF -->
+// <-- Non-regression test for bug 16305 -->
+//
+// <-- Bugzilla URL -->
+// http://bugzilla.scilab.org/16305
+//
+// <-- Short Description -->
+// unwrap(,"unfold") failed unfolding straight segments
+
+x = linspace(0,10,1000);
+y = acos(cos(x));
+r = unwrap(y,'unfold');
+
+Ref = [0. 1.2412412 2.4824825 3.7190723 4.9603135 6.2015547 7.436594 8.6778353 9.9051221];
+assert_checkalmostequal(r(1:124:1000), Ref, 1e-7);
-- 
1.7.9.5