add implementation for kaldi io (by ymz)

1 files changed, 179 insertions, 0 deletions

diff --git a/kaldi_io/src/kaldi/matrix/compressed-matrix.h b/kaldi_io/src/kaldi/matrix/compressed-matrix.h
new file mode 100644
index 0000000..746cab3
--- /dev/null
+++ b/kaldi_io/src/kaldi/matrix/compressed-matrix.h
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+// matrix/compressed-matrix.h
+
+// Copyright 2012  Johns Hopkins University (author: Daniel Povey)
+//                 Frantisek Skala, Wei Shi
+
+// See ../../COPYING for clarification regarding multiple authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+// THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+// WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
+// MERCHANTABLITY OR NON-INFRINGEMENT.
+// See the Apache 2 License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef KALDI_MATRIX_COMPRESSED_MATRIX_H_
+#define KALDI_MATRIX_COMPRESSED_MATRIX_H_ 1
+
+#include "kaldi-matrix.h"
+
+namespace kaldi {
+
+/// \addtogroup matrix_group
+/// @{
+
+/// This class does lossy compression of a matrix.  It only
+/// supports copying to-from a KaldiMatrix.  For large matrices,
+/// each element is compressed into about one byte, but there
+/// is a little overhead on top of that (globally, and also per
+/// column).
+
+/// The basic idea is for each column (in the normal configuration)
+/// we work out the values at the 0th, 25th, 50th and 100th percentiles
+/// and store them as 16-bit integers; we then encode each value in
+/// the column as a single byte, in 3 separate ranges with different
+/// linear encodings (0-25th, 25-50th, 50th-100th).
+/// If the matrix has 8 rows or fewer, we simply store all values as
+/// uint16.
+
+class CompressedMatrix {
+ public:
+  CompressedMatrix(): data_(NULL) { }
+
+  ~CompressedMatrix() { Destroy(); }
+  
+  template<typename Real>
+  CompressedMatrix(const MatrixBase<Real> &mat): data_(NULL) { CopyFromMat(mat); }
+
+  /// Initializer that can be used to select part of an existing
+  /// CompressedMatrix without un-compressing and re-compressing (note: unlike
+  /// similar initializers for class Matrix, it doesn't point to the same memory
+  /// location).
+  CompressedMatrix(const CompressedMatrix &mat,
+                   const MatrixIndexT row_offset,
+                   const MatrixIndexT num_rows,
+                   const MatrixIndexT col_offset,
+                   const MatrixIndexT num_cols);
+
+  void *Data() const { return this->data_; }
+
+  /// This will resize *this and copy the contents of mat to *this.
+  template<typename Real>
+  void CopyFromMat(const MatrixBase<Real> &mat);
+
+  CompressedMatrix(const CompressedMatrix &mat);
+
+  CompressedMatrix &operator = (const CompressedMatrix &mat); // assignment operator.
+
+  template<typename Real>
+  CompressedMatrix &operator = (const MatrixBase<Real> &mat); // assignment operator.
+  
+  /// Copies contents to matrix.  Note: mat must have the correct size,
+  /// CopyToMat no longer attempts to resize it.
+  template<typename Real>
+  void CopyToMat(MatrixBase<Real> *mat) const;
+
+  void Write(std::ostream &os, bool binary) const;
+  
+  void Read(std::istream &is, bool binary);
+
+  /// Returns number of rows (or zero for emtpy matrix).
+  inline MatrixIndexT NumRows() const { return (data_ == NULL) ? 0 :
+      (*reinterpret_cast<GlobalHeader*>(data_)).num_rows; }
+
+  /// Returns number of columns (or zero for emtpy matrix).
+  inline MatrixIndexT NumCols() const { return (data_ == NULL) ? 0 :
+      (*reinterpret_cast<GlobalHeader*>(data_)).num_cols; }
+
+  /// Copies row #row of the matrix into vector v.
+  /// Note: v must have same size as #cols.
+  template<typename Real>
+  void CopyRowToVec(MatrixIndexT row, VectorBase<Real> *v) const;
+
+  /// Copies column #col of the matrix into vector v.
+  /// Note: v must have same size as #rows.
+  template<typename Real>
+  void CopyColToVec(MatrixIndexT col, VectorBase<Real> *v) const;
+
+  /// Copies submatrix of compressed matrix into matrix dest.
+  /// Submatrix starts at row row_offset and column column_offset and its size
+  /// is defined by size of provided matrix dest
+  template<typename Real>
+  void CopyToMat(int32 row_offset,
+                 int32 column_offset,
+                 MatrixBase<Real> *dest) const;
+
+  void Swap(CompressedMatrix *other) { std::swap(data_, other->data_); }
+  
+  friend class Matrix<float>;
+  friend class Matrix<double>;
+ private:
+
+  // allocates data using new [], ensures byte alignment
+  // sufficient for float.
+  static void *AllocateData(int32 num_bytes);
+
+  // the "format" will be 1 for the original format where each column has a
+  // PerColHeader, and 2 for the format now used for matrices with 8 or fewer
+  // rows, where everything is represented as 16-bit integers.
+  struct GlobalHeader {
+    int32 format;
+    float min_value;
+    float range;
+    int32 num_rows;
+    int32 num_cols;
+  };
+
+  static MatrixIndexT DataSize(const GlobalHeader &header);
+
+  struct PerColHeader {
+    uint16 percentile_0;
+    uint16 percentile_25;
+    uint16 percentile_75;
+    uint16 percentile_100;
+  };
+
+  template<typename Real>
+  static void CompressColumn(const GlobalHeader &global_header,
+                             const Real *data, MatrixIndexT stride,
+                             int32 num_rows, PerColHeader *header,
+                             unsigned char *byte_data);
+  template<typename Real>
+  static void ComputeColHeader(const GlobalHeader &global_header,
+                               const Real *data, MatrixIndexT stride,
+                               int32 num_rows, PerColHeader *header);
+
+  static inline uint16 FloatToUint16(const GlobalHeader &global_header,
+                                     float value);
+
+  static inline float Uint16ToFloat(const GlobalHeader &global_header,
+                                    uint16 value);
+  static inline unsigned char FloatToChar(float p0, float p25,
+                                          float p75, float p100,
+                                          float value);
+  static inline float CharToFloat(float p0, float p25,
+                                  float p75, float p100,
+                                  unsigned char value);
+  
+  void Destroy();
+  
+  void *data_; // first GlobalHeader, then PerColHeader (repeated), then
+  // the byte data for each column (repeated).  Note: don't intersperse
+  // the byte data with the PerColHeaders, because of alignment issues.
+
+};
+
+
+/// @} end of \addtogroup matrix_group
+
+
+}  // namespace kaldi
+
+
+#endif  // KALDI_MATRIX_COMPRESSED_MATRIX_H_