Merge pull request #4863 from PDoakORNL/consistent_0_output_tinyvector

[WIP] ReferencePoints report -0.0 is equivalent to 0.0 output either as 0.

src/Containers/OhmmsPETE/TinyVector.h

@@ -38,8 +38,10 @@
 
 // include files
 #include <iomanip>
+#include <cmath>
 #include "PETE/PETE.h"
 #include "OhmmsPETE/OhmmsTinyMeta.h"
+#include "type_traits/complex_help.hpp"
 
 namespace qmcplusplus
 {
@@ -113,7 +115,7 @@ struct TinyVector
   inline int size() const { return D; }
 
   inline TinyVector& operator=(const TinyVector& rhs) = default;
-  inline TinyVector& operator=(TinyVector&& rhs)      = default;
+  inline TinyVector& operator=(TinyVector&& rhs) = default;
 
   template<class T1>
   inline TinyVector<T, D>& operator=(const TinyVector<T1, D>& rhs)
@@ -218,14 +220,26 @@ template<class T>
 struct printTinyVector
 {};
 
-// specialized for Vector<TinyVector<T,D> >
+/** template functor for Vector<TinyVector<T,D> streamn output
+ *  0 equivalent values are output as 0.
+ *  In the case of complex or integer type T's this can be added if needed.
+ *  But now you don't pay for this if unless T is actually real.
+ */
 template<class T, unsigned D>
 struct printTinyVector<TinyVector<T, D>>
 {
   inline static void print(std::ostream& os, const TinyVector<T, D>& r)
   {
     for (int d = 0; d < D; d++)
-      os << std::setw(18) << std::setprecision(10) << r[d];
+      if constexpr(IsComplex_t<T>::value)
+	os << std::setw(18) << std::setprecision(10) << r[d];
+      else if constexpr(IsReal_t<T>::value)
+	if (FP_ZERO == std::fpclassify(r[d]))
+	  os << std::setw(18) << std::setprecision(10) << 0;
+	else
+	  os << std::setw(18) << std::setprecision(10) << r[d];
+      else
+	os << r[d];
   }
 };
 

src/Containers/OhmmsPETE/tests/test_TinyVector.cpp

@@ -16,6 +16,7 @@
 
 #include <stdio.h>
 #include <string>
+#include <iostream>
 
 using std::string;
 
@@ -82,4 +83,13 @@ TEST_CASE("tiny vector", "[OhmmsPETE]")
   test_tiny_vector_size_two<4>();
 }
 
+TEST_CASE("tiny vector operator out", "[OhmmsPETE]")
+{
+  TinyVector<double, 3> point{0.0, -0.0, 1.0};
+  std::ostringstream ostr;
+  ostr << point;
+  std::string expected{"                 0                 0                 1"};
+  CHECK(expected == ostr.str());
+}
+
 } // namespace qmcplusplus

src/type_traits/complex_help.hpp

@@ -26,6 +26,11 @@ struct IsComplex_t<std::complex<T>> : public std::true_type
 
 template<typename T>
 using IsComplex = std::enable_if_t<IsComplex_t<T>::value, bool>;
+
+// for symmetry with IsComplex_t
+template<typename T>
+using IsReal_t = std::is_floating_point<T>;
+
 template<typename T>
 using IsReal = std::enable_if_t<std::is_floating_point<T>::value, bool>;