Matrix Class Reference

Matrix class that supports arbitrary NxN size. More...

#include <Matrix.h>

Collaboration diagram for Matrix:

Public Member Functions
	Matrix (int N)
	Simple constructor of square matrix with initialization to identity matrix. More...
	Matrix (int rows, int cols)
	Simple constructor of rectangular matrix with initialization to zero matrix. More...
	Matrix (const Matrix &other)
	Copy constructor. More...
Matrix &	operator= (const Matrix &matrix)
	Assignment operator. More...
int	cols () const
	Width of matrix. More...
double	determinant () const
	Return the determinant of this matrix. More...
double	get (int row, int col) const
	Return (row, col) element. More...
Matrix	inverse (int significantDigits, MatrixConsistent &matrixConsistent) const
	Return the inverse of this matrix. More...
Matrix	minorReduced (int rowOmit, int colOmit) const
	Return minor matrix which is the original with the specified row and column omitted. The name 'minor' is a reserved word. More...
Matrix	operator* (const Matrix &other) const
	Multiplication operator with a matrix. More...
QVector< double >	operator* (const QVector< double > other) const
	Multiplication operator with a vector. More...
int	rows () const
	Height of matrix. More...
void	set (int row, int col, double value)
	Set (row, col) element. More...
QString	toString () const
	Dump matrix to a string. More...
Matrix	transpose () const
	Return the transpose of the current matrix. More...

Detailed Description

Matrix class that supports arbitrary NxN size.

Definition at line 20 of file Matrix.h.

Constructor & Destructor Documentation

Matrix() [1/3]

Matrix::Matrix

(

int

N

)

Simple constructor of square matrix with initialization to identity matrix.

Definition at line 12 of file Matrix.cpp.

{
  initialize (N, N);
}

Matrix() [2/3]

Matrix::Matrix	(	int	rows,
		int	cols
	)

Simple constructor of rectangular matrix with initialization to zero matrix.

Definition at line 17 of file Matrix.cpp.

{
  initialize (rows, cols);
}

Matrix() [3/3]

Matrix::Matrix

(

const Matrix &

other

)

Copy constructor.

Definition at line 23 of file Matrix.cpp.

{
  m_rows = other.rows();
  m_cols = other.cols();
  m_vector.resize (m_rows * m_cols);
  for (int row = 0; row < m_rows; row++) {
    for (int col = 0; col < m_cols; col++) {
      set (row, col, other.get (row, col));
    }
  }
}

Member Function Documentation

cols()

int Matrix::cols

(

)

const

Width of matrix.

Definition at line 61 of file Matrix.cpp.

{
  return m_cols;
}

determinant()

double Matrix::determinant

(

)

const

Return the determinant of this matrix.

Definition at line 66 of file Matrix.cpp.

{
  ENGAUGE_ASSERT (m_rows == m_cols);

  double rtn;

  if (m_rows == 1) {

    rtn = m_vector [0];

  } else {

    const int COL = 0; // We arbitrarily iterate through the first column

    // This is a recursive algorithm
    rtn = 0.0;
    double multiplier = +1;
    for (int row = 0; row < m_rows; row++) {
      Matrix min = minorReduced (row, COL);
      rtn += multiplier * get (row, COL) * min.determinant ();
      multiplier *= -1.0;
    }
  }

  return rtn;
}

get()

double Matrix::get	(	int	row,
		int	col
	)		const

Return (row, col) element.

Definition at line 98 of file Matrix.cpp.

{
  int foldedIndex = fold2dIndexes (row, col);
  return m_vector [foldedIndex];
}

inverse()

Matrix Matrix::inverse	(	int	significantDigits,
		MatrixConsistent &	matrixConsistent
	)		const

Return the inverse of this matrix.

Parameters

significantDigits	Input value for calculating epsilon threshold for determinants that are so close to zero that matrix should be considered inconsistent.
matrixConsistent	Output flag indicating success or failure

Definition at line 123 of file Matrix.cpp.

{
  // Set epsilon threshold for valueFailsEpsilonTest
  double maxValue = 0;
  for (int row = 0; row < m_rows; row++) {
    for (int col = 0; col < m_cols; col++) {
      double value = qAbs (get (row, col));
      if (value > maxValue) {
        maxValue = value;
      }
    }
  }

  // Available algorithms are inverseCramersRule and inverseGaussianElimination
  matrixConsistent = MATRIX_CONSISTENT;
  return inverseGaussianElimination (significantDigits,
                                     matrixConsistent);
}

minorReduced()

Matrix Matrix::minorReduced	(	int	rowOmit,
		int	colOmit
	)		const

Return minor matrix which is the original with the specified row and column omitted. The name 'minor' is a reserved word.

Definition at line 326 of file Matrix.cpp.

{
  ENGAUGE_ASSERT (m_rows == m_cols);

  Matrix outMinor (m_rows - 1);
  int rowMinor = 0;
  for (int row = 0; row < m_rows; row++) {
    
    if (row != rowOmit) {
      
      int colMinor = 0;
      for (int col = 0; col < m_cols; col++) {

        if (col != colOmit) {

          outMinor.set (rowMinor, colMinor, get (row, col));
          ++colMinor;
        }
      }
      ++rowMinor;
    }
  }

  return outMinor;
}

operator*() [1/2]

Matrix Matrix::operator*

(

const Matrix &

other

)

const

Multiplication operator with a matrix.

Definition at line 386 of file Matrix.cpp.

{
  ENGAUGE_ASSERT (m_cols == other.rows ());

  Matrix out (m_rows, other.cols ());

  for (int row = 0; row < m_rows; row++) {
    for (int col = 0; col < other.cols (); col++) {
      double sum = 0;
      for (int index = 0; index < m_cols; index++) {
        sum += get (row, index) * other.get (index, col);
      }
      out.set (row, col, sum);
    }
  }

  return out;
}

operator*() [2/2]

QVector< double > Matrix::operator*

(

const QVector< double >

other

)

const

Multiplication operator with a vector.

Definition at line 405 of file Matrix.cpp.

{
  ENGAUGE_ASSERT (m_cols == other.size ());

  QVector<double> out;
  out.resize (m_rows);
  for (int row = 0; row < m_rows; row++) {
    double sum = 0;
    for (int col = 0; col < m_cols; col++) {
      sum += get (row, col) * other [col];
    }

    out [row] = sum;
  }

  return out;
}

operator=()

Matrix & Matrix::operator=

(

const Matrix &

matrix

)

Assignment operator.

Definition at line 35 of file Matrix.cpp.

{
  m_rows = other.rows();
  m_cols = other.cols();
  m_vector.resize (m_rows * m_cols);
  for (int row = 0; row < m_rows; row++) {
    for (int col = 0; col < m_cols; col++) {
      set (row, col, other.get (row, col));
    }
  }

  return *this;
}

rows()

int Matrix::rows

(

)

const

Height of matrix.

Definition at line 423 of file Matrix.cpp.

{
  return m_rows;
}

set()

void Matrix::set	(	int	row,
		int	col,
		double	value
	)

Set (row, col) element.

Definition at line 428 of file Matrix.cpp.

{
  m_vector [fold2dIndexes (row, col)] = value;
}

toString()

QString Matrix::toString

(

)

const

Dump matrix to a string.

Definition at line 445 of file Matrix.cpp.

{
  QString out;
  QTextStream str (&out);

  str << "(";
  for (int row = 0; row < rows (); row++) {
    if (row > 0) {
      str << ", ";
    }
    str << "(";
    for (int col = 0; col < cols (); col++) {
      if (col > 0) {
        str << ", ";
      }
      str << get (row, col);
    }
    str << ")";
  }
  str << ")";

  return out;
}

transpose()

Matrix Matrix::transpose

(

)

const

Return the transpose of the current matrix.

Definition at line 469 of file Matrix.cpp.

{
  Matrix out (m_cols, m_rows);

  for (int row = 0; row < m_rows; row++) {
    for (int col = 0; col < m_cols; col++) {
      out.set (col, row, get (row, col));
    }
  }

  return out;
}

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The documentation for this class was generated from the following files:

• Matrix/Matrix.h
• Matrix/Matrix.cpp