comparison DEPENDENCIES/generic/include/boost/graph/detail/permutation.hpp @ 16:2665513ce2d3

Add boost headers

+// (C) Copyright Jeremy Siek 2001.
+// 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_PERMUTATION_HPP
+#define BOOST_PERMUTATION_HPP
+
+#include <vector>
+#include <memory>
+#include <functional>
+#include <algorithm>
+#include <boost/graph/detail/shadow_iterator.hpp>
+
+namespace boost {
+
+template <class Iter1, class Iter2>
+void permute_serial(Iter1 permuter, Iter1 last, Iter2 result)
+{
+#ifdef BOOST_NO_STD_ITERATOR_TRAITS
+  typedef std::ptrdiff_t D:
+#else
+  typedef typename std::iterator_traits<Iter1>::difference_type D;
+#endif
+
+  D n = 0;
+  while (permuter != last) {
+    std::swap(result[n], result[*permuter]);
+    ++n;
+    ++permuter;
+  }
+}
+
+template <class InIter, class RandIterP, class RandIterR>
+void permute_copy(InIter first, InIter last, RandIterP p, RandIterR result)
+{
+#ifdef BOOST_NO_STD_ITERATOR_TRAITS
+  typedef std::ptrdiff_t i = 0;
+#else
+  typename std::iterator_traits<RandIterP>::difference_type i = 0;
+#endif
+  for (; first != last; ++first, ++i)
+    result[p[i]] = *first;
+}
+
+namespace detail {
+
+template <class RandIter, class RandIterPerm, class D, class T>
+void permute_helper(RandIter first, RandIter last, RandIterPerm p, D, T)
+{
+  D i = 0, pi, n = last - first, cycle_start;
+  T tmp;
+  std::vector<int> visited(n, false);
+
+  while (i != n) { // continue until all elements have been processed
+    cycle_start = i;
+    tmp = first[i];
+    do { // walk around a cycle
+      pi = p[i];
+      visited[pi] = true;
+      std::swap(tmp, first[pi]);
+      i = pi;
+    } while (i != cycle_start);
+    
+    // find the next cycle
+    for (i = 0; i < n; ++i)
+      if (visited[i] == false)
+        break;
+  }
+}
+
+} // namespace detail
+
+template <class RandIter, class RandIterPerm>
+void permute(RandIter first, RandIter last, RandIterPerm p)
+{
+  detail::permute_helper(first, last, p, last - first, *first);
+}
+
+
+// Knuth 1.3.3, Vol. 1 p 176
+// modified for zero-based arrays
+// time complexity?
+//
+// WARNING: T must be a signed integer!
+template <class PermIter>
+void invert_permutation(PermIter X, PermIter Xend)
+{
+#ifdef BOOST_NO_STD_ITERATOR_TRAITS
+  typedef std::ptrdiff_t T:
+#else
+  typedef typename std::iterator_traits<PermIter>::value_type T;
+#endif
+  T n = Xend - X;
+  T m = n;
+  T j = -1;
+
+  while (m > 0) {
+    T i = X[m-1] + 1;
+    if (i > 0) {
+      do {
+        X[m-1] = j - 1;
+        j = -m;
+        m = i;
+        i = X[m-1] + 1;
+      } while (i > 0);
+      i = j;
+    }
+    X[m-1] = -i - 1;
+    --m;
+  }
+}
+
+// Takes a "normal" permutation array (and its inverse), and turns it
+// into a BLAS-style permutation array (which can be thought of as a
+// serialized permutation).
+template <class Iter1, class Iter2, class Iter3>
+inline void serialize_permutation(Iter1 q, Iter1 q_end, Iter2 q_inv, Iter3 p)
+{
+#ifdef BOOST_NO_STD_ITERATOR_TRAITS
+  typedef std::ptrdiff_t P1;
+  typedef std::ptrdiff_t P2;
+  typedef std::ptrdiff_t D;
+#else
+  typedef typename std::iterator_traits<Iter1>::value_type P1;
+  typedef typename std::iterator_traits<Iter2>::value_type P2;
+  typedef typename std::iterator_traits<Iter1>::difference_type D;
+#endif
+  D n = q_end - q;
+  for (D i = 0; i < n; ++i) {
+    P1 qi = q[i];
+    P2 qii = q_inv[i];
+    *p++ = qii;
+    std::swap(q[i], q[qii]);
+    std::swap(q_inv[i], q_inv[qi]);
+  }
+}
+
+// Not used anymore, leaving it here for future reference.
+template <typename Iter, typename Compare>
+void merge_sort(Iter first, Iter last, Compare cmp)
+{
+  if (first + 1 < last) {
+    Iter mid = first + (last - first)/2;
+    merge_sort(first, mid, cmp);
+    merge_sort(mid, last, cmp);
+    std::inplace_merge(first, mid, last, cmp);
+  }
+}
+
+
+// time: N log N + 3N + ?
+// space: 2N
+template <class Iter, class IterP, class Cmp, class Alloc>
+inline void sortp(Iter first, Iter last, IterP p, Cmp cmp, Alloc alloc)
+{
+  typedef typename std::iterator_traits<IterP>::value_type P;
+  typedef typename std::iterator_traits<IterP>::difference_type D;
+  D n = last - first;
+  std::vector<P, Alloc> q(n);
+  for (D i = 0; i < n; ++i) 
+    q[i] = i;
+  std::sort(make_shadow_iter(first, q.begin()),
+            make_shadow_iter(last, q.end()),
+            shadow_cmp<Cmp>(cmp));
+  invert_permutation(q.begin(), q.end());
+  std::copy(q.begin(), q.end(), p);
+}
+
+template <class Iter, class IterP, class Cmp>
+inline void sortp(Iter first, Iter last, IterP p, Cmp cmp)
+{
+  typedef typename std::iterator_traits<IterP>::value_type P;  
+  sortp(first, last, p, cmp, std::allocator<P>());
+}
+
+template <class Iter, class IterP>
+inline void sortp(Iter first, Iter last, IterP p)
+{
+  typedef typename std::iterator_traits<Iter>::value_type T;  
+  typedef typename std::iterator_traits<IterP>::value_type P;  
+  sortp(first, last, p, std::less<T>(), std::allocator<P>());
+}
+
+template <class Iter, class IterP, class Cmp, class Alloc>
+inline void sortv(Iter first, Iter last, IterP p, Cmp cmp, Alloc alloc)
+{
+  typedef typename std::iterator_traits<IterP>::value_type P;
+  typedef typename std::iterator_traits<IterP>::difference_type D;
+  D n = last - first;
+  std::vector<P, Alloc> q(n), q_inv(n);
+  for (D i = 0; i < n; ++i) 
+    q_inv[i] = i;
+  std::sort(make_shadow_iter(first, q_inv.begin()), 
+            make_shadow_iter(last, q_inv.end()), 
+            shadow_cmp<Cmp>(cmp));
+  std::copy(q_inv, q_inv.end(), q.begin());
+  invert_permutation(q.begin(), q.end());
+  serialize_permutation(q.begin(), q.end(), q_inv.end(), p);
+}
+
+
+} // namespace boost
+
+#endif // BOOST_PERMUTATION_HPP