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-rw-r--r--klm/lm/search_trie.cc200
1 files changed, 146 insertions, 54 deletions
diff --git a/klm/lm/search_trie.cc b/klm/lm/search_trie.cc
index 182e27f5..12294682 100644
--- a/klm/lm/search_trie.cc
+++ b/klm/lm/search_trie.cc
@@ -1,3 +1,4 @@
+/* This is where the trie is built. It's on-disk. */
#include "lm/search_trie.hh"
#include "lm/lm_exception.hh"
@@ -8,6 +9,7 @@
#include "lm/word_index.hh"
#include "util/ersatz_progress.hh"
#include "util/file_piece.hh"
+#include "util/proxy_iterator.hh"
#include "util/scoped.hh"
#include <algorithm>
@@ -30,43 +32,119 @@ namespace ngram {
namespace trie {
namespace {
-template <unsigned char Order> class FullEntry {
+/* An entry is a n-gram with probability. It consists of:
+ * WordIndex[order]
+ * float probability
+ * backoff probability (omitted for highest order n-gram)
+ * These are stored consecutively in memory. We want to sort them.
+ *
+ * The problem is the length depends on order (but all n-grams being compared
+ * have the same order). Allocating each entry on the heap (i.e. std::vector
+ * or std::string) then sorting pointers is the normal solution. But that's
+ * too memory inefficient. A lot of this code is just here to force std::sort
+ * to work with records where length is specified at runtime (and avoid using
+ * Boost for LM code). I could have used qsort, but the point is to also
+ * support __gnu_cxx:parallel_sort which doesn't have a qsort version.
+ */
+
+class EntryIterator {
public:
- typedef ProbBackoff Weights;
- static const unsigned char kOrder = Order;
+ EntryIterator() {}
- // reverse order
- WordIndex words[Order];
- Weights weights;
+ EntryIterator(void *ptr, std::size_t size) : ptr_(static_cast<uint8_t*>(ptr)), size_(size) {}
- bool operator<(const FullEntry<Order> &other) const {
- for (const WordIndex *i = words, *j = other.words; i != words + Order; ++i, ++j) {
- if (*i < *j) return true;
- if (*i > *j) return false;
- }
- return false;
+ bool operator==(const EntryIterator &other) const {
+ return ptr_ == other.ptr_;
+ }
+ bool operator<(const EntryIterator &other) const {
+ return ptr_ < other.ptr_;
+ }
+ EntryIterator &operator+=(std::ptrdiff_t amount) {
+ ptr_ += amount * size_;
+ return *this;
+ }
+ std::ptrdiff_t operator-(const EntryIterator &other) const {
+ return (ptr_ - other.ptr_) / size_;
}
+
+ const void *Data() const { return ptr_; }
+ void *Data() { return ptr_; }
+ std::size_t EntrySize() const { return size_; }
+
+ private:
+ uint8_t *ptr_;
+ std::size_t size_;
};
-template <unsigned char Order> class ProbEntry {
+class EntryProxy {
public:
- typedef Prob Weights;
- static const unsigned char kOrder = Order;
+ EntryProxy() {}
+
+ EntryProxy(void *ptr, std::size_t size) : inner_(ptr, size) {}
+
+ operator std::string() const {
+ return std::string(reinterpret_cast<const char*>(inner_.Data()), inner_.EntrySize());
+ }
+
+ EntryProxy &operator=(const EntryProxy &from) {
+ memcpy(inner_.Data(), from.inner_.Data(), inner_.EntrySize());
+ return *this;
+ }
+
+ EntryProxy &operator=(const std::string &from) {
+ memcpy(inner_.Data(), from.data(), inner_.EntrySize());
+ return *this;
+ }
+
+ const WordIndex *Indices() const {
+ return static_cast<const WordIndex*>(inner_.Data());
+ }
+
+ private:
+ friend class util::ProxyIterator<EntryProxy>;
+
+ typedef std::string value_type;
- // reverse order
- WordIndex words[Order];
- Weights weights;
+ typedef EntryIterator InnerIterator;
+ InnerIterator &Inner() { return inner_; }
+ const InnerIterator &Inner() const { return inner_; }
+ InnerIterator inner_;
+};
- bool operator<(const ProbEntry<Order> &other) const {
- for (const WordIndex *i = words, *j = other.words; i != words + Order; ++i, ++j) {
- if (*i < *j) return true;
- if (*i > *j) return false;
+typedef util::ProxyIterator<EntryProxy> NGramIter;
+
+class CompareRecords : public std::binary_function<const EntryProxy &, const EntryProxy &, bool> {
+ public:
+ explicit CompareRecords(unsigned char order) : order_(order) {}
+
+ bool operator()(const EntryProxy &first, const EntryProxy &second) const {
+ return Compare(first.Indices(), second.Indices());
+ }
+ bool operator()(const EntryProxy &first, const std::string &second) const {
+ return Compare(first.Indices(), reinterpret_cast<const WordIndex*>(second.data()));
+ }
+ bool operator()(const std::string &first, const EntryProxy &second) const {
+ return Compare(reinterpret_cast<const WordIndex*>(first.data()), second.Indices());
+ }
+ bool operator()(const std::string &first, const std::string &second) const {
+ return Compare(reinterpret_cast<const WordIndex*>(first.data()), reinterpret_cast<const WordIndex*>(first.data()));
+ }
+
+ private:
+ bool Compare(const WordIndex *first, const WordIndex *second) const {
+ const WordIndex *end = first + order_;
+ for (; first != end; ++first, ++second) {
+ if (*first < *second) return true;
+ if (*first > *second) return false;
}
return false;
}
+
+ unsigned char order_;
};
void WriteOrThrow(FILE *to, const void *data, size_t size) {
+ assert(size);
if (1 != std::fwrite(data, size, 1, to)) UTIL_THROW(util::ErrnoException, "Short write; requested size " << size);
}
@@ -84,21 +162,24 @@ void CopyOrThrow(FILE *from, FILE *to, size_t size) {
}
}
-template <class Entry> std::string DiskFlush(const Entry *begin, const Entry *end, const std::string &file_prefix, std::size_t batch) {
+std::string DiskFlush(const void *mem_begin, const void *mem_end, const std::string &file_prefix, std::size_t batch, unsigned char order, std::size_t weights_size) {
+ const std::size_t entry_size = sizeof(WordIndex) * order + weights_size;
+ const std::size_t prefix_size = sizeof(WordIndex) * (order - 1);
std::stringstream assembled;
- assembled << file_prefix << static_cast<unsigned int>(Entry::kOrder) << '_' << batch;
+ assembled << file_prefix << static_cast<unsigned int>(order) << '_' << batch;
std::string ret(assembled.str());
util::scoped_FILE out(fopen(ret.c_str(), "w"));
if (!out.get()) UTIL_THROW(util::ErrnoException, "Couldn't open " << assembled.str().c_str() << " for writing");
- for (const Entry *group_begin = begin; group_begin != end;) {
- const Entry *group_end = group_begin;
- for (++group_end; (group_end != end) && !memcmp(group_begin->words, group_end->words, sizeof(WordIndex) * (Entry::kOrder - 1)); ++group_end) {}
- WriteOrThrow(out.get(), group_begin->words, sizeof(WordIndex) * (Entry::kOrder - 1));
- WordIndex group_size = group_end - group_begin;
+ // Compress entries that being with the same (order-1) words.
+ for (const uint8_t *group_begin = static_cast<const uint8_t*>(mem_begin); group_begin != static_cast<const uint8_t*>(mem_end);) {
+ const uint8_t *group_end = group_begin;
+ for (group_end += entry_size; (group_end != static_cast<const uint8_t*>(mem_end)) && !memcmp(group_begin, group_end, prefix_size); group_end += entry_size) {}
+ WriteOrThrow(out.get(), group_begin, prefix_size);
+ WordIndex group_size = (group_end - group_begin) / entry_size;
WriteOrThrow(out.get(), &group_size, sizeof(group_size));
- for (const Entry *i = group_begin; i != group_end; ++i) {
- WriteOrThrow(out.get(), &i->words[Entry::kOrder - 1], sizeof(WordIndex));
- WriteOrThrow(out.get(), &i->weights, sizeof(typename Entry::Weights));
+ for (const uint8_t *i = group_begin; i != group_end; i += entry_size) {
+ WriteOrThrow(out.get(), i + prefix_size, sizeof(WordIndex));
+ WriteOrThrow(out.get(), i + sizeof(WordIndex) * order, weights_size);
}
group_begin = group_end;
}
@@ -219,25 +300,37 @@ void MergeSortedFiles(const char *first_name, const char *second_name, const cha
}
}
-template <class Entry> void ConvertToSorted(util::FilePiece &f, const SortedVocabulary &vocab, const std::vector<uint64_t> &counts, util::scoped_memory &mem, const std::string &file_prefix) {
- ConvertToSorted<FullEntry<Entry::kOrder - 1> >(f, vocab, counts, mem, file_prefix);
-
- ReadNGramHeader(f, Entry::kOrder);
- const size_t count = counts[Entry::kOrder - 1];
- const size_t batch_size = std::min(count, mem.size() / sizeof(Entry));
- Entry *const begin = reinterpret_cast<Entry*>(mem.get());
+void ConvertToSorted(util::FilePiece &f, const SortedVocabulary &vocab, const std::vector<uint64_t> &counts, util::scoped_memory &mem, const std::string &file_prefix, unsigned char order) {
+ if (order == 1) return;
+ ConvertToSorted(f, vocab, counts, mem, file_prefix, order - 1);
+
+ ReadNGramHeader(f, order);
+ const size_t count = counts[order - 1];
+ // Size of weights. Does it include backoff?
+ const size_t words_size = sizeof(WordIndex) * order;
+ const size_t weights_size = sizeof(float) + ((order == counts.size()) ? 0 : sizeof(float));
+ const size_t entry_size = words_size + weights_size;
+ const size_t batch_size = std::min(count, mem.size() / entry_size);
+ uint8_t *const begin = reinterpret_cast<uint8_t*>(mem.get());
std::deque<std::string> files;
for (std::size_t batch = 0, done = 0; done < count; ++batch) {
- Entry *out = begin;
- Entry *out_end = out + std::min(count - done, batch_size);
- for (; out != out_end; ++out) {
- ReadNGram(f, Entry::kOrder, vocab, out->words, out->weights);
+ uint8_t *out = begin;
+ uint8_t *out_end = out + std::min(count - done, batch_size) * entry_size;
+ if (order == counts.size()) {
+ for (; out != out_end; out += entry_size) {
+ ReadNGram(f, order, vocab, reinterpret_cast<WordIndex*>(out), *reinterpret_cast<Prob*>(out + words_size));
+ }
+ } else {
+ for (; out != out_end; out += entry_size) {
+ ReadNGram(f, order, vocab, reinterpret_cast<WordIndex*>(out), *reinterpret_cast<ProbBackoff*>(out + words_size));
+ }
}
- //__gnu_parallel::sort(begin, out_end);
- std::sort(begin, out_end);
+ // TODO: __gnu_parallel::sort here.
+ EntryProxy proxy_begin(begin, entry_size), proxy_end(out_end, entry_size);
+ std::sort(NGramIter(proxy_begin), NGramIter(proxy_end), CompareRecords(order));
- files.push_back(DiskFlush(begin, out_end, file_prefix, batch));
- done += out_end - begin;
+ files.push_back(DiskFlush(begin, out_end, file_prefix, batch, order, weights_size));
+ done += (out_end - begin) / entry_size;
}
// All individual files created. Merge them.
@@ -245,9 +338,9 @@ template <class Entry> void ConvertToSorted(util::FilePiece &f, const SortedVoca
std::size_t merge_count = 0;
while (files.size() > 1) {
std::stringstream assembled;
- assembled << file_prefix << static_cast<unsigned int>(Entry::kOrder) << "_merge_" << (merge_count++);
+ assembled << file_prefix << static_cast<unsigned int>(order) << "_merge_" << (merge_count++);
files.push_back(assembled.str());
- MergeSortedFiles(files[0].c_str(), files[1].c_str(), files.back().c_str(), sizeof(typename Entry::Weights), Entry::kOrder);
+ MergeSortedFiles(files[0].c_str(), files[1].c_str(), files.back().c_str(), weights_size, order);
if (std::remove(files[0].c_str())) UTIL_THROW(util::ErrnoException, "Could not remove " << files[0]);
files.pop_front();
if (std::remove(files[0].c_str())) UTIL_THROW(util::ErrnoException, "Could not remove " << files[0]);
@@ -255,14 +348,12 @@ template <class Entry> void ConvertToSorted(util::FilePiece &f, const SortedVoca
}
if (!files.empty()) {
std::stringstream assembled;
- assembled << file_prefix << static_cast<unsigned int>(Entry::kOrder) << "_merged";
+ assembled << file_prefix << static_cast<unsigned int>(order) << "_merged";
std::string merged_name(assembled.str());
if (std::rename(files[0].c_str(), merged_name.c_str())) UTIL_THROW(util::ErrnoException, "Could not rename " << files[0].c_str() << " to " << merged_name.c_str());
}
}
-template <> void ConvertToSorted<FullEntry<1> >(util::FilePiece &/*f*/, const SortedVocabulary &/*vocab*/, const std::vector<uint64_t> &/*counts*/, util::scoped_memory &/*mem*/, const std::string &/*file_prefix*/) {}
-
void ARPAToSortedFiles(util::FilePiece &f, const std::vector<uint64_t> &counts, std::size_t buffer, const std::string &file_prefix, SortedVocabulary &vocab) {
{
std::string unigram_name = file_prefix + "unigrams";
@@ -275,7 +366,7 @@ void ARPAToSortedFiles(util::FilePiece &f, const std::vector<uint64_t> &counts,
util::scoped_memory mem;
mem.reset(malloc(buffer), buffer, util::scoped_memory::ARRAY_ALLOCATED);
if (!mem.get()) UTIL_THROW(util::ErrnoException, "malloc failed for sort buffer size " << buffer);
- ConvertToSorted<ProbEntry<5> >(f, vocab, counts, mem, file_prefix);
+ ConvertToSorted(f, vocab, counts, mem, file_prefix, counts.size());
ReadEnd(f);
}
@@ -390,7 +481,8 @@ void TrieSearch::InitializeFromARPA(const char *file, util::FilePiece &f, const
temporary_directory.resize(strlen(temporary_directory.c_str()));
// Add directory delimiter. Assumes a real operating system.
temporary_directory += '/';
- ARPAToSortedFiles(f, counts, config.building_memory, temporary_directory.c_str(), vocab);
+ // At least 1MB sorting memory.
+ ARPAToSortedFiles(f, counts, std::max<size_t>(config.building_memory, 1048576), temporary_directory.c_str(), vocab);
BuildTrie(temporary_directory.c_str(), counts, config.messages, *this);
if (rmdir(temporary_directory.c_str())) {
std::cerr << "Failed to delete " << temporary_directory << std::endl;
generated by cgit v1.2.3 (git 2.39.1) at 2024-09-21 12:46:39 +0000