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      1 //===------ Math.h - PBQP Vector and Matrix classes -------------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 
     10 #ifndef LLVM_CODEGEN_PBQP_MATH_H
     11 #define LLVM_CODEGEN_PBQP_MATH_H
     12 
     13 #include <cassert>
     14 #include <algorithm>
     15 #include <functional>
     16 
     17 namespace PBQP {
     18 
     19 typedef float PBQPNum;
     20 
     21 /// \brief PBQP Vector class.
     22 class Vector {
     23   public:
     24 
     25     /// \brief Construct a PBQP vector of the given size.
     26     explicit Vector(unsigned length) :
     27       length(length), data(new PBQPNum[length]) {
     28       }
     29 
     30     /// \brief Construct a PBQP vector with initializer.
     31     Vector(unsigned length, PBQPNum initVal) :
     32       length(length), data(new PBQPNum[length]) {
     33         std::fill(data, data + length, initVal);
     34       }
     35 
     36     /// \brief Copy construct a PBQP vector.
     37     Vector(const Vector &v) :
     38       length(v.length), data(new PBQPNum[length]) {
     39         std::copy(v.data, v.data + length, data);
     40       }
     41 
     42     /// \brief Destroy this vector, return its memory.
     43     ~Vector() { delete[] data; }
     44 
     45     /// \brief Assignment operator.
     46     Vector& operator=(const Vector &v) {
     47       delete[] data;
     48       length = v.length;
     49       data = new PBQPNum[length];
     50       std::copy(v.data, v.data + length, data);
     51       return *this;
     52     }
     53 
     54     /// \brief Return the length of the vector
     55     unsigned getLength() const {
     56       return length;
     57     }
     58 
     59     /// \brief Element access.
     60     PBQPNum& operator[](unsigned index) {
     61       assert(index < length && "Vector element access out of bounds.");
     62       return data[index];
     63     }
     64 
     65     /// \brief Const element access.
     66     const PBQPNum& operator[](unsigned index) const {
     67       assert(index < length && "Vector element access out of bounds.");
     68       return data[index];
     69     }
     70 
     71     /// \brief Add another vector to this one.
     72     Vector& operator+=(const Vector &v) {
     73       assert(length == v.length && "Vector length mismatch.");
     74       std::transform(data, data + length, v.data, data, std::plus<PBQPNum>());
     75       return *this;
     76     }
     77 
     78     /// \brief Subtract another vector from this one.
     79     Vector& operator-=(const Vector &v) {
     80       assert(length == v.length && "Vector length mismatch.");
     81       std::transform(data, data + length, v.data, data, std::minus<PBQPNum>());
     82       return *this;
     83     }
     84 
     85     /// \brief Returns the index of the minimum value in this vector
     86     unsigned minIndex() const {
     87       return std::min_element(data, data + length) - data;
     88     }
     89 
     90   private:
     91     unsigned length;
     92     PBQPNum *data;
     93 };
     94 
     95 /// \brief Output a textual representation of the given vector on the given
     96 ///        output stream.
     97 template <typename OStream>
     98 OStream& operator<<(OStream &os, const Vector &v) {
     99   assert((v.getLength() != 0) && "Zero-length vector badness.");
    100 
    101   os << "[ " << v[0];
    102   for (unsigned i = 1; i < v.getLength(); ++i) {
    103     os << ", " << v[i];
    104   }
    105   os << " ]";
    106 
    107   return os;
    108 }
    109 
    110 
    111 /// \brief PBQP Matrix class
    112 class Matrix {
    113   public:
    114 
    115     /// \brief Construct a PBQP Matrix with the given dimensions.
    116     Matrix(unsigned rows, unsigned cols) :
    117       rows(rows), cols(cols), data(new PBQPNum[rows * cols]) {
    118     }
    119 
    120     /// \brief Construct a PBQP Matrix with the given dimensions and initial
    121     /// value.
    122     Matrix(unsigned rows, unsigned cols, PBQPNum initVal) :
    123       rows(rows), cols(cols), data(new PBQPNum[rows * cols]) {
    124         std::fill(data, data + (rows * cols), initVal);
    125     }
    126 
    127     /// \brief Copy construct a PBQP matrix.
    128     Matrix(const Matrix &m) :
    129       rows(m.rows), cols(m.cols), data(new PBQPNum[rows * cols]) {
    130         std::copy(m.data, m.data + (rows * cols), data);
    131     }
    132 
    133     /// \brief Destroy this matrix, return its memory.
    134     ~Matrix() { delete[] data; }
    135 
    136     /// \brief Assignment operator.
    137     Matrix& operator=(const Matrix &m) {
    138       delete[] data;
    139       rows = m.rows; cols = m.cols;
    140       data = new PBQPNum[rows * cols];
    141       std::copy(m.data, m.data + (rows * cols), data);
    142       return *this;
    143     }
    144 
    145     /// \brief Return the number of rows in this matrix.
    146     unsigned getRows() const { return rows; }
    147 
    148     /// \brief Return the number of cols in this matrix.
    149     unsigned getCols() const { return cols; }
    150 
    151     /// \brief Matrix element access.
    152     PBQPNum* operator[](unsigned r) {
    153       assert(r < rows && "Row out of bounds.");
    154       return data + (r * cols);
    155     }
    156 
    157     /// \brief Matrix element access.
    158     const PBQPNum* operator[](unsigned r) const {
    159       assert(r < rows && "Row out of bounds.");
    160       return data + (r * cols);
    161     }
    162 
    163     /// \brief Returns the given row as a vector.
    164     Vector getRowAsVector(unsigned r) const {
    165       Vector v(cols);
    166       for (unsigned c = 0; c < cols; ++c)
    167         v[c] = (*this)[r][c];
    168       return v;
    169     }
    170 
    171     /// \brief Returns the given column as a vector.
    172     Vector getColAsVector(unsigned c) const {
    173       Vector v(rows);
    174       for (unsigned r = 0; r < rows; ++r)
    175         v[r] = (*this)[r][c];
    176       return v;
    177     }
    178 
    179     /// \brief Reset the matrix to the given value.
    180     Matrix& reset(PBQPNum val = 0) {
    181       std::fill(data, data + (rows * cols), val);
    182       return *this;
    183     }
    184 
    185     /// \brief Set a single row of this matrix to the given value.
    186     Matrix& setRow(unsigned r, PBQPNum val) {
    187       assert(r < rows && "Row out of bounds.");
    188       std::fill(data + (r * cols), data + ((r + 1) * cols), val);
    189       return *this;
    190     }
    191 
    192     /// \brief Set a single column of this matrix to the given value.
    193     Matrix& setCol(unsigned c, PBQPNum val) {
    194       assert(c < cols && "Column out of bounds.");
    195       for (unsigned r = 0; r < rows; ++r)
    196         (*this)[r][c] = val;
    197       return *this;
    198     }
    199 
    200     /// \brief Matrix transpose.
    201     Matrix transpose() const {
    202       Matrix m(cols, rows);
    203       for (unsigned r = 0; r < rows; ++r)
    204         for (unsigned c = 0; c < cols; ++c)
    205           m[c][r] = (*this)[r][c];
    206       return m;
    207     }
    208 
    209     /// \brief Returns the diagonal of the matrix as a vector.
    210     ///
    211     /// Matrix must be square.
    212     Vector diagonalize() const {
    213       assert(rows == cols && "Attempt to diagonalize non-square matrix.");
    214 
    215       Vector v(rows);
    216       for (unsigned r = 0; r < rows; ++r)
    217         v[r] = (*this)[r][r];
    218       return v;
    219     }
    220 
    221     /// \brief Add the given matrix to this one.
    222     Matrix& operator+=(const Matrix &m) {
    223       assert(rows == m.rows && cols == m.cols &&
    224           "Matrix dimensions mismatch.");
    225       std::transform(data, data + (rows * cols), m.data, data,
    226           std::plus<PBQPNum>());
    227       return *this;
    228     }
    229 
    230     /// \brief Returns the minimum of the given row
    231     PBQPNum getRowMin(unsigned r) const {
    232       assert(r < rows && "Row out of bounds");
    233       return *std::min_element(data + (r * cols), data + ((r + 1) * cols));
    234     }
    235 
    236     /// \brief Returns the minimum of the given column
    237     PBQPNum getColMin(unsigned c) const {
    238       PBQPNum minElem = (*this)[0][c];
    239       for (unsigned r = 1; r < rows; ++r)
    240         if ((*this)[r][c] < minElem) minElem = (*this)[r][c];
    241       return minElem;
    242     }
    243 
    244     /// \brief Subtracts the given scalar from the elements of the given row.
    245     Matrix& subFromRow(unsigned r, PBQPNum val) {
    246       assert(r < rows && "Row out of bounds");
    247       std::transform(data + (r * cols), data + ((r + 1) * cols),
    248           data + (r * cols),
    249           std::bind2nd(std::minus<PBQPNum>(), val));
    250       return *this;
    251     }
    252 
    253     /// \brief Subtracts the given scalar from the elements of the given column.
    254     Matrix& subFromCol(unsigned c, PBQPNum val) {
    255       for (unsigned r = 0; r < rows; ++r)
    256         (*this)[r][c] -= val;
    257       return *this;
    258     }
    259 
    260     /// \brief Returns true if this is a zero matrix.
    261     bool isZero() const {
    262       return find_if(data, data + (rows * cols),
    263           std::bind2nd(std::not_equal_to<PBQPNum>(), 0)) ==
    264         data + (rows * cols);
    265     }
    266 
    267   private:
    268     unsigned rows, cols;
    269     PBQPNum *data;
    270 };
    271 
    272 /// \brief Output a textual representation of the given matrix on the given
    273 ///        output stream.
    274 template <typename OStream>
    275 OStream& operator<<(OStream &os, const Matrix &m) {
    276 
    277   assert((m.getRows() != 0) && "Zero-row matrix badness.");
    278 
    279   for (unsigned i = 0; i < m.getRows(); ++i) {
    280     os << m.getRowAsVector(i);
    281   }
    282 
    283   return os;
    284 }
    285 
    286 }
    287 
    288 #endif // LLVM_CODEGEN_PBQP_MATH_H
    289