Line data    Source code

       1             : // SPDX-License-Identifier: BSD-3-Clause
       2             : // Copyright (c) 2023 Scipp contributors (https://github.com/scipp)
       3             : /// @file
       4             : /// @author Simon Heybrock
       5             : #pragma once
       6             : 
       7             : #include <algorithm>
       8             : #include <tuple>
       9             : 
      10             : #include "scipp/core/except.h"
      11             : 
      12             : namespace scipp::core {
      13             : 
      14             : /// Return params for computing bin index for linear edges (constant bin width).
      15    22895631 : constexpr static auto linear_edge_params = [](const auto &edges) {
      16    22895631 :   auto len = scipp::size(edges) - 1;
      17    22895631 :   const auto offset = edges.front();
      18    22895631 :   const auto nbin = len;
      19    22895631 :   const auto scale = static_cast<double>(nbin) / (edges.back() - edges.front());
      20    22895631 :   return std::tuple{offset, nbin, scale};
      21             : };
      22             : 
      23             : namespace expect::histogram {
      24        1334 : template <class T> void sorted_edges(const T &edges) {
      25        1334 :   if (!std::is_sorted(edges.begin(), edges.end()))
      26           1 :     throw except::BinEdgeError("Bin edges of histogram must be sorted.");
      27        1333 : }
      28             : } // namespace expect::histogram
      29             : 
      30             : template <class Index, class T, class Edges, class Params>
      31    30910276 : Index get_bin(const T &x, const Edges &edges, const Params &params) {
      32             :   // Explicitly check for x outside edges here as otherwise we may run into an
      33             :   // integer overflow when converting the "bin" computation result to `Index`.
      34    30910276 :   if (x < edges.front() || x >= edges.back())
      35      109985 :     return -1;
      36    30800291 :   const auto [offset, nbin, scale] = params;
      37    30800291 :   Index bin = (x - offset) * scale;
      38    30800291 :   bin = std::clamp(bin, Index(0), Index(nbin - 1));
      39    30800291 :   if (x < edges[bin]) {
      40          88 :     return bin - 1;
      41    30800203 :   } else if (x >= edges[bin + 1]) {
      42        2220 :     return bin + 1;
      43             :   } else {
      44    30797983 :     return bin;
      45             :   }
      46             : }
      47             : 
      48             : } // namespace scipp::core