update boost

linx64/include/boost/histogram/algorithm/empty.hpp

@@ -0,0 +1,36 @@
+// Copyright 2019 Henry Schreiner
+//
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt
+// or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_HISTOGRAM_ALGORITHM_EMPTY_HPP
+#define BOOST_HISTOGRAM_ALGORITHM_EMPTY_HPP
+
+#include <boost/histogram/fwd.hpp>
+#include <boost/histogram/indexed.hpp>
+
+namespace boost {
+namespace histogram {
+namespace algorithm {
+/** Check to see if all histogram cells are empty. Use coverage to include or
+  exclude the underflow/overflow bins.
+
+  This algorithm has O(N) complexity, where N is the number of cells.
+
+  Returns true if all cells are empty, and false otherwise.
+ */
+template <class A, class S>
+auto empty(const histogram<A, S>& h, coverage cov) {
+  using value_type = typename histogram<A, S>::value_type;
+  const value_type default_value = value_type();
+  for (auto&& ind : indexed(h, cov)) {
+    if (*ind != default_value) { return false; }
+  }
+  return true;
+}
+} // namespace algorithm
+} // namespace histogram
+} // namespace boost
+
+#endif