Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 61 insertions, 0 deletions

diff --git a/src/boost/libs/histogram/examples/guide_fill_histogram.cpp b/src/boost/libs/histogram/examples/guide_fill_histogram.cpp
new file mode 100644
index 000000000..172be66e0
--- /dev/null
+++ b/src/boost/libs/histogram/examples/guide_fill_histogram.cpp
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+// Copyright 2015-2018 Hans Dembinski
+//
+// 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)
+
+//[ guide_fill_histogram
+
+#include <boost/histogram.hpp>
+#include <cassert>
+#include <functional>
+#include <numeric>
+#include <utility>
+#include <vector>
+
+int main() {
+  using namespace boost::histogram;
+
+  auto h = make_histogram(axis::integer<>(0, 3), axis::regular<>(2, 0.0, 1.0));
+
+  // fill histogram, number of arguments must be equal to number of axes,
+  // types must be convertible to axis value type (here integer and double)
+  h(0, 0.2); // increase a cell value by one
+  h(2, 0.5); // increase another cell value by one
+
+  // fills from a tuple are also supported; passing a tuple of wrong size
+  // causes an error at compile-time or an assertion at runtime in debug mode
+  auto xy = std::make_tuple(1, 0.3);
+  h(xy);
+
+  // chunk-wise filling is also supported and more efficient, make some data...
+  std::vector<double> xy2[2] = {{0, 2, 5}, {0.8, 0.4, 0.7}};
+
+  // ... and call fill method
+  h.fill(xy2);
+
+  // once histogram is filled, access individual cells using operator[] or at(...)
+  // - operator[] can only accept a single argument in the current version of C++,
+  //   it is convenient when you have a 1D histogram
+  // - at(...) can accept several values, so use this by default
+  // - underflow bins are at index -1, overflow bins at index `size()`
+  // - passing an invalid index triggers a std::out_of_range exception
+  assert(h.at(0, 0) == 1);
+  assert(h.at(0, 1) == 1);
+  assert(h.at(1, 0) == 1);
+  assert(h.at(1, 1) == 0);
+  assert(h.at(2, 0) == 1);
+  assert(h.at(2, 1) == 1);
+  assert(h.at(-1, -1) == 0); // underflow for axis 0 and 1
+  assert(h.at(-1, 0) == 0);  // underflow for axis 0, normal bin for axis 1
+  assert(h.at(-1, 2) == 0);  // underflow for axis 0, overflow for axis 1
+  assert(h.at(3, 1) == 1);   // overflow for axis 0, normal bin for axis 1
+
+  // iteration over values works, but see next example for a better way
+  // - iteration using begin() and end() includes under- and overflow bins
+  // - iteration order is an implementation detail and should not be relied upon
+  const double sum = std::accumulate(h.begin(), h.end(), 0.0);
+  assert(sum == 6);
+}
+
+//]