faster with static_vector

examples/speed_vs_root.cpp

@@ -43,7 +43,7 @@ void compare_1d(unsigned n)
 
   double best_root = std::numeric_limits<double>::max();
   double best_boost = std::numeric_limits<double>::max();
-  for (unsigned k = 0; k < 3; ++k) {
+  for (unsigned k = 0; k < 10; ++k) {
     TH1I hroot("", "", 100, 0, 1);
     clock_t t = clock();
     for (unsigned i = 0; i < n; ++i)
@@ -72,7 +72,7 @@ void compare_3d(unsigned n)
 
   double best_root = std::numeric_limits<double>::max();
   double best_boost = std::numeric_limits<double>::max();
-  for (unsigned k = 0; k < 3; ++k) {
+  for (unsigned k = 0; k < 10; ++k) {
     TH3I hroot("", "", 100, 0, 1, 100, 0, 1, 100, 0, 1);
     clock_t t = clock();
     for (unsigned i = 0; i < n; ++i)
@@ -102,7 +102,7 @@ void compare_6d(unsigned n)
 
   double best_root = std::numeric_limits<double>::max();
   double best_boost = std::numeric_limits<double>::max();
-  for (unsigned k = 0; k < 3; ++k) {
+  for (unsigned k = 0; k < 10; ++k) {
     double x[6];
     vector<int> bin(6, 10);
     vector<double> min(6, 0);

include/boost/histogram/axis.hpp

@@ -248,8 +248,6 @@ typedef variant<
   integer_axis
 > axis_type;
 
-typedef std::vector<axis_type> axes_type;
-
 std::ostream& operator<<(std::ostream&, const axis_type&);
 
 }

include/boost/histogram/histogram.hpp

@@ -172,7 +172,7 @@ private:
     ar & data_;
   }
 
-  friend class buffer_access;
+  friend class histogram_access;
 };
 
 histogram operator+(const histogram& a, const histogram& b) {

include/boost/histogram/histogram_base.hpp

@@ -9,6 +9,7 @@
 #include <boost/serialization/split_member.hpp>
 #include <boost/serialization/variant.hpp>
 #include <boost/serialization/vector.hpp>
+#include <boost/container/static_vector.hpp>
 #include <boost/type_traits/is_same.hpp>
 
 #include <bitset>
@@ -21,7 +22,8 @@ namespace histogram {
 // holds an array of axis and computes the internal index
 class histogram_base {
 public:
-  typedef uint64_t size_type;
+  typedef container::static_vector<axis_type, BOOST_HISTOGRAM_AXIS_LIMIT> axes_type;
+  typedef uintptr_t size_type;
 
   histogram_base(const histogram_base&);
   histogram_base& operator=(const histogram_base&);
@@ -55,7 +57,7 @@ protected:
     update_buffers();                                                \
   }
 
-// generates constructors taking 2 to AXIS_LIMIT arguments
+// generates constructors taking 1 to AXIS_LIMIT arguments
 BOOST_PP_REPEAT_FROM_TO(1, BOOST_HISTOGRAM_AXIS_LIMIT, BOOST_HISTOGRAM_BASE_CTOR, nil)
 
   bool operator==(const histogram_base&) const;
@@ -106,9 +108,15 @@ private:
   void serialize(Archive& ar, unsigned version)
   {
     using namespace serialization;
-    ar & axes_;
+    unsigned size = axes_.size();
-    if (Archive::is_loading::value)
+    ar & size;
+    if (Archive::is_loading::value) {
+      axes_.resize(size);
+      ar & serialization::make_array(&axes_[0], size);
       update_buffers();
+    } else {
+      ar & serialization::make_array(&axes_[0], size);
+    }
   }
 };
 

src/python/histogram.cpp

@@ -29,7 +29,7 @@ histogram_init(python::tuple args, python::dict kwargs) {
     }
 
     // normal constructor
-    axes_type axes;
+    histogram_base::axes_type axes;
     for (unsigned i = 1, n = len(args); i < n; ++i) {
         object pa = args[i];
         extract<regular_axis> er(pa);
@@ -135,7 +135,7 @@ histogram_getitem(const histogram& self, python::object oidx) {
     return self.value(self.dim(), idx);
 }
 
-class buffer_access {
+class histogram_access {
 public:
     static
     python::dict
@@ -161,8 +161,8 @@ void register_histogram()
     >("histogram", no_init)
         .def("__init__", raw_function(histogram_init))
         // shadowed C++ ctors
-        .def(init<const axes_type&>())
+        .def(init<const histogram_base::axes_type&>())
-        .add_property("__array_interface__", &buffer_access::histogram_array_interface)
+        .add_property("__array_interface__", &histogram_access::histogram_array_interface)
         .def("fill", raw_function(histogram_fill))
         .add_property("depth", &histogram::depth)
         .add_property("sum", &histogram::sum)

src/python/histogram_base.cpp

@@ -275,7 +275,7 @@ void register_histogram_base() {
   // used to pass arguments from raw python init to specialized C++ constructors
   class_<std::vector<double> >("vector_double", no_init);
   class_<std::vector<std::string> >("vector_string", no_init);
-  class_<axes_type>("axes", no_init);
+  class_<histogram_base::axes_type>("axes", no_init);
 
   class_<regular_axis>("regular_axis", no_init)
     .def(init<unsigned, double, double, std::string, bool>(