BUG: Fixes NaNs generated from qu2ax when quaternion is "<0,0,0>1"

Signed-off-by: Michael Jackson <mike.jackson@bluequartz.net>

Author: imikejackson

CMakeLists.txt

@@ -15,7 +15,7 @@ set(CMAKE_CXX_EXTENSIONS OFF)
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
 # set project's name
-project(EbsdLibProj VERSION 1.0.36)
+project(EbsdLibProj VERSION 1.0.37)
 
 # ---------- Setup output Directories -------------------------
 set(CMAKE_LIBRARY_OUTPUT_DIRECTORY
@@ -94,7 +94,7 @@ endif()
 set(EbsdLib_USE_GHC_FILESYSTEM OFF)
 
 if(APPLE)
-  exec_program(uname ARGS -v  OUTPUT_VARIABLE DARWIN_VERSION)
+  execute_process(COMMAND uname -v OUTPUT_VARIABLE DARWIN_VERSION)
   string(REGEX MATCH "[0-9]+" DARWIN_VERSION ${DARWIN_VERSION})
   if(DARWIN_VERSION VERSION_LESS 19)
     message(STATUS "The current macOS System is too old to compile and will fail. Please set the EbsdLib_USE_GHC_FILESYSTEM=ON variable to allow Ebsdlib to compile")

Source/EbsdLib/Core/OrientationTransformation.hpp

@@ -1368,24 +1368,46 @@ OutputType qu2ax(const InputType& q, typename Quaternion<typename OutputType::va
   {
     qo[i] = sign * q[i];
   }
-  OutputValueType eps = static_cast<OutputValueType>(1.0e-12L);
+
   OutputValueType omega = static_cast<OutputValueType>(2.0 * acos(qo[w]));
+  // If omega equals zero then return the rotation axis as [001]
+  OutputValueType eps = static_cast<OutputValueType>(1.0e-12L);
   if(omega < eps)
   {
     res[0] = 0.0;
     res[1] = 0.0;
     res[2] = static_cast<OutputValueType>(1.0 * epsijk);
     res[3] = 0.0;
+    return res;
+  }
+
+  if(qo[w] != 0.0)
+  {
+    typename OutputType::value_type mag = sqrt(q[x] * q[x] + q[y] * q[y] + q[z] * q[z]);
+    if(mag == 0.0)
+    {
+      res[0] = 0.0;
+      res[1] = 0.0;
+      res[2] = static_cast<OutputValueType>(1.0 * epsijk);
+      res[3] = 0.0;
+    }
+    else
+    {
+      mag = static_cast<OutputValueType>(1.0 / mag);
+      res[0] = q[x] * mag;
+      res[1] = q[y] * mag;
+      res[2] = q[z] * mag;
+      res[3] = omega;
+    }
   }
   else
   {
-    typename OutputType::value_type mag = 0.0;
-    mag = static_cast<OutputValueType>(1.0 / sqrt(q[x] * q[x] + q[y] * q[y] + q[z] * q[z]));
-    res[0] = q[x] * mag;
-    res[1] = q[y] * mag;
-    res[2] = q[z] * mag;
-    res[3] = omega;
+    res[0] = q[x];
+    res[1] = q[y];
+    res[2] = q[z];
+    res[3] = EbsdLib::Constants::k_PiD;
   }
+
   return res;
 }