# HG changeset patch
# User Alpar Juttner <alpar@cs.elte.hu>
# Date 1228213050 0
# Node ID 31d224a3c0af0f0ae35ac7264d0a90eb1871648e
# Parent 4f7224faf3bd0bf460965b685cd503a838251df9
Doc improvements and source unification in radix_sort (#72)
diff -r 4f7224faf3bd -r 31d224a3c0af lemon/radix_sort.h
--- a/lemon/radix_sort.h Fri Oct 17 23:55:18 2008 +0200
+++ b/lemon/radix_sort.h Tue Dec 02 10:17:30 2008 +0000
@@ -1,6 +1,6 @@
-/* -*- C++ -*-
+/* -*- mode: C++; indent-tabs-mode: nil; -*-
*
- * This file is a part of LEMON, a generic C++ optimization library
+ * This file is a part of LEMON, a generic C++ optimization library.
*
* Copyright (C) 2003-2008
* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
@@ -37,93 +37,93 @@
template <typename Value>
struct Identity {
const Value& operator()(const Value& val) {
- return val;
+ return val;
}
};
template <typename Value, typename Iterator, typename Functor>
- Iterator radixSortPartition(Iterator first, Iterator last,
- Functor functor, Value mask) {
+ Iterator radixSortPartition(Iterator first, Iterator last,
+ Functor functor, Value mask) {
while (first != last && !(functor(*first) & mask)) {
- ++first;
+ ++first;
}
if (first == last) {
- return first;
+ return first;
}
--last;
while (first != last && (functor(*last) & mask)) {
- --last;
+ --last;
}
if (first == last) {
- return first;
+ return first;
}
std::iter_swap(first, last);
++first;
if (!(first < last)) {
- return first;
+ return first;
}
while (true) {
- while (!(functor(*first) & mask)) {
- ++first;
- }
- --last;
- while (functor(*last) & mask) {
- --last;
- }
- if (!(first < last)) {
- return first;
- }
- std::iter_swap(first, last);
- ++first;
+ while (!(functor(*first) & mask)) {
+ ++first;
+ }
+ --last;
+ while (functor(*last) & mask) {
+ --last;
+ }
+ if (!(first < last)) {
+ return first;
+ }
+ std::iter_swap(first, last);
+ ++first;
}
}
template <typename Iterator, typename Functor>
- Iterator radixSortSignPartition(Iterator first, Iterator last,
- Functor functor) {
+ Iterator radixSortSignPartition(Iterator first, Iterator last,
+ Functor functor) {
while (first != last && functor(*first) < 0) {
- ++first;
+ ++first;
}
if (first == last) {
- return first;
+ return first;
}
--last;
while (first != last && functor(*last) >= 0) {
- --last;
+ --last;
}
if (first == last) {
- return first;
+ return first;
}
std::iter_swap(first, last);
++first;
if (!(first < last)) {
- return first;
+ return first;
}
while (true) {
- while (functor(*first) < 0) {
- ++first;
- }
- --last;
- while (functor(*last) >= 0) {
- --last;
- }
- if (!(first < last)) {
- return first;
- }
- std::iter_swap(first, last);
- ++first;
+ while (functor(*first) < 0) {
+ ++first;
+ }
+ --last;
+ while (functor(*last) >= 0) {
+ --last;
+ }
+ if (!(first < last)) {
+ return first;
+ }
+ std::iter_swap(first, last);
+ ++first;
}
}
template <typename Value, typename Iterator, typename Functor>
- void radixIntroSort(Iterator first, Iterator last,
- Functor functor, Value mask) {
+ void radixIntroSort(Iterator first, Iterator last,
+ Functor functor, Value mask) {
while (mask != 0 && last - first > 1) {
- Iterator cut = radixSortPartition(first, last, functor, mask);
- mask >>= 1;
- radixIntroSort(first, cut, functor, mask);
- first = cut;
+ Iterator cut = radixSortPartition(first, last, functor, mask);
+ mask >>= 1;
+ radixIntroSort(first, cut, functor, mask);
+ first = cut;
}
}
@@ -138,19 +138,19 @@
mask = ~0; max_digit = 0;
for (it = first; it != cut; ++it) {
- while ((mask & functor(*it)) != mask) {
- ++max_digit;
- mask <<= 1;
- }
+ while ((mask & functor(*it)) != mask) {
+ ++max_digit;
+ mask <<= 1;
+ }
}
radixIntroSort(first, cut, functor, 1 << max_digit);
mask = 0; max_digit = 0;
for (it = cut; it != last; ++it) {
- while ((mask | functor(*it)) != mask) {
- ++max_digit;
- mask <<= 1; mask |= 1;
- }
+ while ((mask | functor(*it)) != mask) {
+ ++max_digit;
+ mask <<= 1; mask |= 1;
+ }
}
radixIntroSort(cut, last, functor, 1 << max_digit);
}
@@ -163,21 +163,21 @@
Iterator it;
for (it = first; it != last; ++it) {
- while ((mask | functor(*it)) != mask) {
- ++max_digit;
- mask <<= 1; mask |= 1;
- }
+ while ((mask | functor(*it)) != mask) {
+ ++max_digit;
+ mask <<= 1; mask |= 1;
+ }
}
radixIntroSort(first, last, functor, 1 << max_digit);
}
- template <typename Value,
- bool sign = std::numeric_limits<Value>::is_signed >
+ template <typename Value,
+ bool sign = std::numeric_limits<Value>::is_signed >
struct RadixSortSelector {
template <typename Iterator, typename Functor>
static void sort(Iterator first, Iterator last, Functor functor) {
- radixSignedSort<Value>(first, last, functor);
+ radixSignedSort<Value>(first, last, functor);
}
};
@@ -185,7 +185,7 @@
struct RadixSortSelector<Value, false> {
template <typename Iterator, typename Functor>
static void sort(Iterator first, Iterator last, Functor functor) {
- radixUnsignedSort<Value>(first, last, functor);
+ radixUnsignedSort<Value>(first, last, functor);
}
};
@@ -195,26 +195,29 @@
///
/// \brief Sorts the STL compatible range into ascending order.
///
- /// The \c radixSort sorts the STL compatible range into ascending
- /// order. The radix sort algorithm can sort the items which mapped
- /// to an integer with an adaptable unary function \c functor and the
- /// order will be ascending by these mapped values. As function
- /// specialization it is possible to use a normal function instead
- /// of the functor object or if the functor is not given it will use
- /// an identity function instead.
+ /// The \c radixSort sorts an STL compatible range into ascending
+ /// order. The radix sort algorithm can sort items which are mapped
+ /// to integers with an adaptable unary function \c functor and the
+ /// order will be ascending according to these mapped values.
///
- /// This implemented radix sort is a special quick sort which pivot
- /// value is choosen to partite the items on the next
- /// bit. Therefore, let be \c c the maximal capacity and \c n the
- /// number of the items in the container, the time complexity of the
- /// algorithm is \f$ O(\log(c)n) \f$ and the additional space
- /// complexity is \f$ O(\log(c)) \f$.
+ /// It is also possible to use a normal function instead
+ /// of the functor object. If the functor is not given it will use
+ /// the identity function instead.
+ ///
+ /// This is a special quick sort algorithm where the pivot
+ /// values to split the items are choosen to be \f$ 2^k \f$ for each \c k.
+ /// Therefore, the time complexity of the
+ /// algorithm is \f$ O(\log(c)n) \f$ and it uses \f$ O(\log(c)) \f$,
+ /// additional space, where \c c is the maximal value and \c n is the
+ /// number of the items in the container.
///
/// \param first The begin of the given range.
/// \param last The end of the given range.
/// \param functor An adaptible unary function or a normal function
/// which maps the items to any integer type which can be either
/// signed or unsigned.
+ ///
+ /// \sa counterSort()
template <typename Iterator, typename Functor>
void radixSort(Iterator first, Iterator last, Functor functor) {
using namespace _radix_sort_bits;
@@ -261,63 +264,63 @@
}
template <typename Functor, typename Key>
- void counterIntroSort(Key *first, Key *last, Key *target,
- int byte, Functor functor) {
- const int size =
- unsigned(std::numeric_limits<unsigned char>::max()) + 1;
+ void counterIntroSort(Key *first, Key *last, Key *target,
+ int byte, Functor functor) {
+ const int size =
+ unsigned(std::numeric_limits<unsigned char>::max()) + 1;
std::vector<int> counter(size);
for (int i = 0; i < size; ++i) {
- counter[i] = 0;
+ counter[i] = 0;
}
Key *it = first;
while (first != last) {
- ++counter[valueByte(functor(*first), byte)];
- ++first;
+ ++counter[valueByte(functor(*first), byte)];
+ ++first;
}
int prev, num = 0;
for (int i = 0; i < size; ++i) {
- prev = num;
- num += counter[i];
- counter[i] = prev;
+ prev = num;
+ num += counter[i];
+ counter[i] = prev;
}
while (it != last) {
- target[counter[valueByte(functor(*it), byte)]++] = *it;
- ++it;
+ target[counter[valueByte(functor(*it), byte)]++] = *it;
+ ++it;
}
}
template <typename Functor, typename Key>
- void signedCounterIntroSort(Key *first, Key *last, Key *target,
- int byte, Functor functor) {
- const int size =
- unsigned(std::numeric_limits<unsigned char>::max()) + 1;
+ void signedCounterIntroSort(Key *first, Key *last, Key *target,
+ int byte, Functor functor) {
+ const int size =
+ unsigned(std::numeric_limits<unsigned char>::max()) + 1;
std::vector<int> counter(size);
for (int i = 0; i < size; ++i) {
- counter[i] = 0;
+ counter[i] = 0;
}
Key *it = first;
while (first != last) {
- counter[valueByte(functor(*first), byte)]++;
- ++first;
+ counter[valueByte(functor(*first), byte)]++;
+ ++first;
}
int prev, num = 0;
for (int i = size / 2; i < size; ++i) {
- prev = num;
- num += counter[i];
- counter[i] = prev;
+ prev = num;
+ num += counter[i];
+ counter[i] = prev;
}
for (int i = 0; i < size / 2; ++i) {
- prev = num;
- num += counter[i];
- counter[i] = prev;
+ prev = num;
+ num += counter[i];
+ counter[i] = prev;
}
while (it != last) {
- target[counter[valueByte(functor(*it), byte)]++] = *it;
- ++it;
+ target[counter[valueByte(functor(*it), byte)]++] = *it;
+ ++it;
}
}
-
+
template <typename Value, typename Iterator, typename Functor>
void counterSignedSort(Iterator first, Iterator last, Functor functor) {
if (first == last) return;
@@ -328,30 +331,30 @@
int length = std::distance(first, last);
Key* buffer = allocator.allocate(2 * length);
try {
- bool dir = true;
- std::copy(first, last, buffer);
- for (int i = 0; i < int(sizeof(Value)) - 1; ++i) {
- if (dir) {
- counterIntroSort(buffer, buffer + length, buffer + length,
- i, functor);
- } else {
- counterIntroSort(buffer + length, buffer + 2 * length, buffer,
- i, functor);
- }
- dir = !dir;
- }
- if (dir) {
- signedCounterIntroSort(buffer, buffer + length, buffer + length,
- sizeof(Value) - 1, functor);
- std::copy(buffer + length, buffer + 2 * length, first);
- } else {
- signedCounterIntroSort(buffer + length, buffer + 2 * length, buffer,
- sizeof(Value) - 1, functor);
- std::copy(buffer, buffer + length, first);
- }
+ bool dir = true;
+ std::copy(first, last, buffer);
+ for (int i = 0; i < int(sizeof(Value)) - 1; ++i) {
+ if (dir) {
+ counterIntroSort(buffer, buffer + length, buffer + length,
+ i, functor);
+ } else {
+ counterIntroSort(buffer + length, buffer + 2 * length, buffer,
+ i, functor);
+ }
+ dir = !dir;
+ }
+ if (dir) {
+ signedCounterIntroSort(buffer, buffer + length, buffer + length,
+ sizeof(Value) - 1, functor);
+ std::copy(buffer + length, buffer + 2 * length, first);
+ } else {
+ signedCounterIntroSort(buffer + length, buffer + 2 * length, buffer,
+ sizeof(Value) - 1, functor);
+ std::copy(buffer, buffer + length, first);
+ }
} catch (...) {
- allocator.deallocate(buffer, 2 * length);
- throw;
+ allocator.deallocate(buffer, 2 * length);
+ throw;
}
allocator.deallocate(buffer, 2 * length);
}
@@ -366,38 +369,38 @@
int length = std::distance(first, last);
Key *buffer = allocator.allocate(2 * length);
try {
- bool dir = true;
- std::copy(first, last, buffer);
- for (int i = 0; i < int(sizeof(Value)); ++i) {
- if (dir) {
- counterIntroSort(buffer, buffer + length,
- buffer + length, i, functor);
- } else {
- counterIntroSort(buffer + length, buffer + 2 * length,
- buffer, i, functor);
- }
- dir = !dir;
- }
- if (dir) {
- std::copy(buffer, buffer + length, first);
- } else {
- std::copy(buffer + length, buffer + 2 * length, first);
- }
+ bool dir = true;
+ std::copy(first, last, buffer);
+ for (int i = 0; i < int(sizeof(Value)); ++i) {
+ if (dir) {
+ counterIntroSort(buffer, buffer + length,
+ buffer + length, i, functor);
+ } else {
+ counterIntroSort(buffer + length, buffer + 2 * length,
+ buffer, i, functor);
+ }
+ dir = !dir;
+ }
+ if (dir) {
+ std::copy(buffer, buffer + length, first);
+ } else {
+ std::copy(buffer + length, buffer + 2 * length, first);
+ }
} catch (...) {
- allocator.deallocate(buffer, 2 * length);
- throw;
+ allocator.deallocate(buffer, 2 * length);
+ throw;
}
allocator.deallocate(buffer, 2 * length);
}
- template <typename Value,
- bool sign = std::numeric_limits<Value>::is_signed >
+ template <typename Value,
+ bool sign = std::numeric_limits<Value>::is_signed >
struct CounterSortSelector {
template <typename Iterator, typename Functor>
static void sort(Iterator first, Iterator last, Functor functor) {
- counterSignedSort<Value>(first, last, functor);
+ counterSignedSort<Value>(first, last, functor);
}
};
@@ -405,7 +408,7 @@
struct CounterSortSelector<Value, false> {
template <typename Iterator, typename Functor>
static void sort(Iterator first, Iterator last, Functor functor) {
- counterUnsignedSort<Value>(first, last, functor);
+ counterUnsignedSort<Value>(first, last, functor);
}
};
@@ -413,34 +416,33 @@
/// \ingroup auxalg
///
- /// \brief Sorts stable the STL compatible range into ascending order.
+ /// \brief Sorts the STL compatible range into ascending order in a stable
+ /// way.
///
- /// The \c counterSort sorts the STL compatible range into ascending
- /// order. The counter sort algorithm can sort the items which
- /// mapped to an integer with an adaptable unary function \c functor
- /// and the order will be ascending by these mapped values. As
- /// function specialization it is possible to use a normal function
- /// instead of the functor object or if the functor is not given it
- /// will use an identity function instead.
+ /// This function sorts an STL compatible range into ascending
+ /// order according to an integer mapping in the same as radixSort() does.
///
- /// The implemented counter sort use a radix forward sort on the
+ /// This sorting algorithm is stable, i.e. the order of two equal
+ /// element remains the same after the sorting.
+ ///
+ /// This sort algorithm use a radix forward sort on the
/// bytes of the integer number. The algorithm sorts the items
- /// byte-by-byte, first it counts how many times occurs a byte value
- /// in the containerm, and with the occurence number the container
- /// can be copied to an other in asceding order in \c O(n) time.
- /// Let be \c c the maximal capacity of the integer type and \c n
- /// the number of the items in the container, the time complexity of
- /// the algorithm is \f$ O(\log(c)n) \f$ and the additional space
- /// complexity is \f$ O(n) \f$.
+ /// byte-by-byte. First, it counts how many times a byte value occurs
+ /// in the container, then it copies the corresponding items to
+ /// another container in asceding order in \c O(n) time.
///
- /// The sorting algorithm is stable, i.e. the order of two equal
- /// element remains the same.
+ /// The time complexity of the algorithm is \f$ O(\log(c)n) \f$ and
+ /// it uses \f$ O(n) \f$, additional space, where \c c is the
+ /// maximal value and \c n is the number of the items in the
+ /// container.
///
+
/// \param first The begin of the given range.
/// \param last The end of the given range.
/// \param functor An adaptible unary function or a normal function
/// which maps the items to any integer type which can be either
/// signed or unsigned.
+ /// \sa radixSort()
template <typename Iterator, typename Functor>
void counterSort(Iterator first, Iterator last, Functor functor) {
using namespace _radix_sort_bits;
diff -r 4f7224faf3bd -r 31d224a3c0af test/radix_sort_test.cc
--- a/test/radix_sort_test.cc Fri Oct 17 23:55:18 2008 +0200
+++ b/test/radix_sort_test.cc Tue Dec 02 10:17:30 2008 +0000
@@ -1,6 +1,6 @@
-/* -*- C++ -*-
+/* -*- mode: C++; indent-tabs-mode: nil; -*-
*
- * This file is a part of LEMON, a generic C++ optimization library
+ * This file is a part of LEMON, a generic C++ optimization library.
*
* Copyright (C) 2003-2008
* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
@@ -81,8 +81,8 @@
check(data1[i] == data2[n - 1 - i], "Test failed");
}
- }
-
+ }
+
{
std::vector<unsigned char> data1(n);
generateCharSequence(n, data1);
@@ -121,7 +121,7 @@
for (int i = 0; i < n; ++i) {
check(data1[i] == data2[n - 1 - i], "Test failed");
}
- }
+ }
{
std::vector<unsigned char> data1(n);
@@ -140,7 +140,7 @@
int main() {
- checkRadixSort();
+ checkRadixSort();
checkCounterSort();
return 0;