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//===---------------- PBQP.cpp --------- PBQP Solver ------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Developed by: Bernhard Scholz
// The Univesity of Sydney
// http://www.it.usyd.edu.au/~scholz
//===----------------------------------------------------------------------===//
// TODO:
//
// * Default to null costs on vector initialisation?
// * C++-ify the rest of the solver.
#ifndef LLVM_CODEGEN_PBQPSOLVER_H
#define LLVM_CODEGEN_PBQPSOLVER_H
#include <cassert>
#include <algorithm>
#include <functional>
namespace llvm {
//! \brief Floating point type to use in PBQP solver.
typedef double PBQPNum;
//! \brief PBQP Vector class.
class PBQPVector {
public:
//! \brief Construct a PBQP vector of the given size.
explicit PBQPVector(unsigned length) :
length(length), data(new PBQPNum[length]) {
std::fill(data, data + length, 0);
}
//! \brief Copy construct a PBQP vector.
PBQPVector(const PBQPVector &v) :
length(v.length), data(new PBQPNum[length]) {
std::copy(v.data, v.data + length, data);
}
~PBQPVector() { delete[] data; }
//! \brief Assignment operator.
PBQPVector& operator=(const PBQPVector &v) {
delete[] data;
length = v.length;
data = new PBQPNum[length];
std::copy(v.data, v.data + length, data);
return *this;
}
//! \brief Return the length of the vector
unsigned getLength() const throw () {
return length;
}
//! \brief Element access.
PBQPNum& operator[](unsigned index) {
assert(index < length && "PBQPVector element access out of bounds.");
return data[index];
}
//! \brief Const element access.
const PBQPNum& operator[](unsigned index) const {
assert(index < length && "PBQPVector element access out of bounds.");
return data[index];
}
//! \brief Add another vector to this one.
PBQPVector& operator+=(const PBQPVector &v) {
assert(length == v.length && "PBQPVector length mismatch.");
std::transform(data, data + length, v.data, data, std::plus<PBQPNum>());
return *this;
}
//! \brief Subtract another vector from this one.
PBQPVector& operator-=(const PBQPVector &v) {
assert(length == v.length && "PBQPVector length mismatch.");
std::transform(data, data + length, v.data, data, std::minus<PBQPNum>());
return *this;
}
//! \brief Returns the index of the minimum value in this vector
unsigned minIndex() const {
return std::min_element(data, data + length) - data;
}
private:
unsigned length;
PBQPNum *data;
};
//! \brief PBQP Matrix class
class PBQPMatrix {
public:
//! \brief Construct a PBQP Matrix with the given dimensions.
PBQPMatrix(unsigned rows, unsigned cols) :
rows(rows), cols(cols), data(new PBQPNum[rows * cols]) {
std::fill(data, data + (rows * cols), 0);
}
//! \brief Copy construct a PBQP matrix.
PBQPMatrix(const PBQPMatrix &m) :
rows(m.rows), cols(m.cols), data(new PBQPNum[rows * cols]) {
std::copy(m.data, m.data + (rows * cols), data);
}
~PBQPMatrix() { delete[] data; }
//! \brief Assignment operator.
PBQPMatrix& operator=(const PBQPMatrix &m) {
delete[] data;
rows = m.rows; cols = m.cols;
data = new PBQPNum[rows * cols];
std::copy(m.data, m.data + (rows * cols), data);
return *this;
}
//! \brief Return the number of rows in this matrix.
unsigned getRows() const throw () { return rows; }
//! \brief Return the number of cols in this matrix.
unsigned getCols() const throw () { return cols; }
//! \brief Matrix element access.
PBQPNum* operator[](unsigned r) {
assert(r < rows && "Row out of bounds.");
return data + (r * cols);
}
//! \brief Matrix element access.
const PBQPNum* operator[](unsigned r) const {
assert(r < rows && "Row out of bounds.");
return data + (r * cols);
}
//! \brief Returns the given row as a vector.
PBQPVector getRowAsVector(unsigned r) const {
PBQPVector v(cols);
for (unsigned c = 0; c < cols; ++c)
v[c] = (*this)[r][c];
return v;
}
//! \brief Reset the matrix to the given value.
PBQPMatrix& reset(PBQPNum val = 0) {
std::fill(data, data + (rows * cols), val);
return *this;
}
//! \brief Set a single row of this matrix to the given value.
PBQPMatrix& setRow(unsigned r, PBQPNum val) {
assert(r < rows && "Row out of bounds.");
std::fill(data + (r * cols), data + ((r + 1) * cols), val);
return *this;
}
//! \brief Set a single column of this matrix to the given value.
PBQPMatrix& setCol(unsigned c, PBQPNum val) {
assert(c < cols && "Column out of bounds.");
for (unsigned r = 0; r < rows; ++r)
(*this)[r][c] = val;
return *this;
}
//! \brief Matrix transpose.
PBQPMatrix transpose() const {
PBQPMatrix m(cols, rows);
for (unsigned r = 0; r < rows; ++r)
for (unsigned c = 0; c < cols; ++c)
m[c][r] = (*this)[r][c];
return m;
}
//! \brief Returns the diagonal of the matrix as a vector.
//!
//! Matrix must be square.
PBQPVector diagonalize() const {
assert(rows == cols && "Attempt to diagonalize non-square matrix.");
PBQPVector v(rows);
for (unsigned r = 0; r < rows; ++r)
v[r] = (*this)[r][r];
return v;
}
//! \brief Add the given matrix to this one.
PBQPMatrix& operator+=(const PBQPMatrix &m) {
assert(rows == m.rows && cols == m.cols &&
"Matrix dimensions mismatch.");
std::transform(data, data + (rows * cols), m.data, data,
std::plus<PBQPNum>());
return *this;
}
//! \brief Returns the minimum of the given row
PBQPNum getRowMin(unsigned r) const {
assert(r < rows && "Row out of bounds");
return *std::min_element(data + (r * cols), data + ((r + 1) * cols));
}
//! \brief Returns the minimum of the given column
PBQPNum getColMin(unsigned c) const {
PBQPNum minElem = (*this)[0][c];
for (unsigned r = 1; r < rows; ++r)
if ((*this)[r][c] < minElem) minElem = (*this)[r][c];
return minElem;
}
//! \brief Subtracts the given scalar from the elements of the given row.
PBQPMatrix& subFromRow(unsigned r, PBQPNum val) {
assert(r < rows && "Row out of bounds");
std::transform(data + (r * cols), data + ((r + 1) * cols),
data + (r * cols),
std::bind2nd(std::minus<PBQPNum>(), val));
return *this;
}
//! \brief Subtracts the given scalar from the elements of the given column.
PBQPMatrix& subFromCol(unsigned c, PBQPNum val) {
for (unsigned r = 0; r < rows; ++r)
(*this)[r][c] -= val;
return *this;
}
//! \brief Returns true if this is a zero matrix.
bool isZero() const {
return find_if(data, data + (rows * cols),
std::bind2nd(std::not_equal_to<PBQPNum>(), 0)) ==
data + (rows * cols);
}
private:
unsigned rows, cols;
PBQPNum *data;
};
#define EPS (1E-8)
#ifndef PBQP_TYPE
#define PBQP_TYPE
struct pbqp;
typedef struct pbqp pbqp;
#endif
/*****************
* PBQP routines *
*****************/
/* allocate pbqp problem */
pbqp *alloc_pbqp(int num);
/* add node costs */
void add_pbqp_nodecosts(pbqp *this_,int u, PBQPVector *costs);
/* add edge mat */
void add_pbqp_edgecosts(pbqp *this_,int u,int v,PBQPMatrix *costs);
/* solve PBQP problem */
void solve_pbqp(pbqp *this_);
/* get solution of a node */
int get_pbqp_solution(pbqp *this_,int u);
/* alloc PBQP */
pbqp *alloc_pbqp(int num);
/* free PBQP */
void free_pbqp(pbqp *this_);
/* is optimal */
bool is_pbqp_optimal(pbqp *this_);
}
#endif
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