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Java library with basic matrix implementations
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/*
* Copyright (C) 2014-2024 Philip Helger (www.helger.com)
* philip[at]helger[dot]com
*
* 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
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.helger.matrix;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.Reader;
import java.io.Serializable;
import java.io.StreamTokenizer;
import java.text.NumberFormat;
import java.util.Arrays;
import java.util.Locale;
import java.util.Random;
import java.util.concurrent.ThreadLocalRandom;
import javax.annotation.CheckReturnValue;
import javax.annotation.Nonnegative;
import javax.annotation.Nonnull;
import javax.annotation.WillNotClose;
import com.helger.commons.ValueEnforcer;
import com.helger.commons.annotation.ReturnsMutableCopy;
import com.helger.commons.collection.impl.CommonsArrayList;
import com.helger.commons.collection.impl.ICommonsList;
import com.helger.commons.hashcode.HashCodeGenerator;
import com.helger.commons.io.stream.StreamHelper;
import com.helger.commons.lang.ICloneable;
import com.helger.commons.math.MathHelper;
import com.helger.commons.string.StringHelper;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
/**
* Jama = Java Matrix class.
*
* The Java Matrix Class provides the fundamental operations of numerical linear
* algebra. Various constructors create Matrices from two dimensional arrays of
* double precision floating point numbers. Various "gets" and "sets" provide
* access to submatrices and matrix elements. Several methods implement basic
* matrix arithmetic, including matrix addition and multiplication, matrix
* norms, and element-by-element array operations. Methods for reading and
* printing matrices are also included. All the operations in this version of
* the Matrix Class involve real matrices. Complex matrices may be handled in a
* future version.
*
*
* Five fundamental matrix decompositions, which consist of pairs or triples of
* matrices, permutation vectors, and the like, produce results in five
* decomposition classes. These decompositions are accessed by the Matrix class
* to compute solutions of simultaneous linear equations, determinants, inverses
* and other matrix functions. The five decompositions are:
*
*
* - Cholesky Decomposition of symmetric, positive definite matrices.
*
- LU Decomposition of rectangular matrices.
*
- QR Decomposition of rectangular matrices.
*
- Singular Value Decomposition of rectangular matrices.
*
- Eigenvalue Decomposition of both symmetric and nonsymmetric square
* matrices.
*
*
* - Example of use:
* - Solve a linear system A x = b and compute the residual norm, ||b - A x||.
*
*
* double [] [] vals = { { 1., 2., 3 }, { 4., 5., 6. }, { 7., 8., 10. } };
* Matrix A = new Matrix (vals);
* Matrix b = Matrix.random (3, 1);
* Matrix x = A.solve (b);
* Matrix r = A.times (x).minus (b);
* double rnorm = r.normInf ();
*
*
*
*
*
* @author The MathWorks, Inc. and the National Institute of Standards and
* Technology.
* @version 5 August 1998
*/
public class MatrixInt implements ICloneable , Serializable
{
/**
* Array for internal storage of elements.
*
* @serial internal array storage.
*/
private final int [] [] m_aData;
/**
* Row dimensions.
*
* @serial row dimension.
*/
private final int m_nRows;
/**
* Column dimensions.
*
* @serial column dimension.
*/
private final int m_nCols;
/**
* Construct an nRows-by-nCols matrix of zeros.
*
* @param nRows
* Number of rows.
* @param nCols
* Number of columns.
*/
public MatrixInt (@Nonnegative final int nRows, @Nonnegative final int nCols)
{
ValueEnforcer.isGT0 (nRows, "Rows");
ValueEnforcer.isGT0 (nCols, "Cols");
m_nRows = nRows;
m_nCols = nCols;
m_aData = new int [nRows] [nCols];
}
/**
* Construct an nRows-by-nCols constant matrix.
*
* @param nRows
* Number of rows.
* @param nCols
* Number of columns.
* @param nValue
* Fill the matrix with this scalar value.
*/
public MatrixInt (@Nonnegative final int nRows, @Nonnegative final int nCols, final int nValue)
{
this (nRows, nCols);
for (int nRow = 0; nRow < nRows; nRow++)
Arrays.fill (m_aData[nRow], nValue);
}
/**
* Construct a matrix from a 2-D array.
*
* @param aOther
* Two-dimensional array of doubles.
* @exception IllegalArgumentException
* All rows must have the same length
* @see #constructWithCopy
*/
@SuppressFBWarnings ("EI_EXPOSE_REP")
MatrixInt (@Nonnull final int [] [] aOther)
{
ValueEnforcer.notNull (aOther, "Other");
ValueEnforcer.isGT0 (aOther.length, "rows");
ValueEnforcer.isGT0 (aOther[0].length, "cols");
m_nRows = aOther.length;
m_nCols = aOther[0].length;
for (int nRow = 0; nRow < m_nRows; nRow++)
if (aOther[nRow].length != m_nCols)
throw new IllegalArgumentException ("All rows must have the same length.");
m_aData = aOther;
}
/**
* Construct a matrix quickly without checking arguments.
*
* @param aOther
* Two-dimensional array of doubles. Is directly reused!
* @param nRows
* Number of rows.
* @param nCols
* Number of columns.
*/
@SuppressFBWarnings ("EI_EXPOSE_REP")
MatrixInt (@Nonnull final int [] [] aOther, @Nonnegative final int nRows, @Nonnegative final int nCols)
{
ValueEnforcer.notNull (aOther, "Other");
ValueEnforcer.isGT0 (nRows, "rows");
ValueEnforcer.isGT0 (nCols, "cols");
ValueEnforcer.isTrue (aOther.length >= nRows, "array is too short");
for (int nRow = 0; nRow < nRows; nRow++)
ValueEnforcer.isTrue (aOther[nRow].length >= nCols, "All rows must have the same length.");
m_aData = aOther;
m_nRows = nRows;
m_nCols = nCols;
}
/**
* Construct a matrix from a one-dimensional packed array
*
* @param aVals
* One-dimensional array of doubles, packed by columns (ala Fortran).
* @param nRows
* Number of rows.
* @exception IllegalArgumentException
* Array length must be a multiple of nRows.
*/
public MatrixInt (@Nonnull final int [] aVals, @Nonnegative final int nRows)
{
m_nRows = nRows;
m_nCols = (nRows != 0 ? aVals.length / nRows : 0);
if (nRows * m_nCols != aVals.length)
throw new IllegalArgumentException ("Array length must be a multiple of nRows.");
m_aData = new int [nRows] [m_nCols];
for (int nRow = 0; nRow < nRows; nRow++)
{
final int [] aRow = m_aData[nRow];
for (int nCol = 0; nCol < m_nCols; nCol++)
aRow[nCol] = aVals[nRow + nCol * nRows];
}
}
/**
* Construct a matrix from a copy of a 2-D array.
*
* @param aArray
* Two-dimensional array of doubles.
* @return The new matrix
* @exception IllegalArgumentException
* All rows must have the same length
*/
@Nonnull
public static MatrixInt constructWithCopy (@Nonnull final int [] [] aArray)
{
final int nRows = aArray.length;
final int nCols = aArray[0].length;
final MatrixInt aCopy = new MatrixInt (nRows, nCols);
final int [] [] aCopyArray = aCopy.internalGetArray ();
for (int nRow = 0; nRow < nRows; nRow++)
{
final int [] aSrcRow = aArray[nRow];
final int [] aDstRow = aCopyArray[nRow];
if (aSrcRow.length != nCols)
throw new IllegalArgumentException ("All rows must have the same length.");
System.arraycopy (aSrcRow, 0, aDstRow, 0, aSrcRow.length);
}
return aCopy;
}
/**
* @return a deep copy of a matrix
*/
@Nonnull
@ReturnsMutableCopy
public MatrixInt getClone ()
{
final MatrixInt aCopy = new MatrixInt (m_nRows, m_nCols);
final int [] [] aCopyArray = aCopy.m_aData;
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aSrcRow = m_aData[nRow];
final int [] aDstRow = aCopyArray[nRow];
System.arraycopy (aSrcRow, 0, aDstRow, 0, aSrcRow.length);
}
return aCopy;
}
/**
* Access the internal two-dimensional array.
*
* @return Pointer to the two-dimensional array of matrix elements.
*/
@SuppressFBWarnings ("EI_EXPOSE_REP")
@Nonnull
public int [] [] internalGetArray ()
{
return m_aData;
}
/**
* Copy the internal two-dimensional array.
*
* @return Two-dimensional array copy of matrix elements.
*/
@Nonnull
@ReturnsMutableCopy
public int [] [] getArrayCopy ()
{
final int [] [] aArray = new int [m_nRows] [m_nCols];
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aSrcRow = m_aData[nRow];
final int [] aDstRow = aArray[nRow];
System.arraycopy (aSrcRow, 0, aDstRow, 0, m_nCols);
}
return aArray;
}
/**
* Make a one-dimensional column packed copy of the internal array.
*
* @return Matrix elements packed in a one-dimensional array by columns.
*/
@Nonnull
public int [] getColumnPackedCopy ()
{
final int [] ret = new int [m_nRows * m_nCols];
for (int nCol = 0; nCol < m_nCols; nCol++)
{
final int nRowIndex = nCol * m_nRows;
for (int nRow = 0; nRow < m_nRows; nRow++)
ret[nRow + nRowIndex] = m_aData[nRow][nCol];
}
return ret;
}
/**
* Make a one-dimensional row packed copy of the internal array.
*
* @return Matrix elements packed in a one-dimensional array by rows.
*/
@Nonnull
public int [] getRowPackedCopy ()
{
final int [] ret = new int [m_nRows * m_nCols];
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aSrcRow = m_aData[nRow];
for (int nCol = 0; nCol < m_nCols; nCol++)
ret[nRow * m_nCols + nCol] = aSrcRow[nCol];
}
return ret;
}
/**
* Get row dimension.
*
* @return nRows, the number of rows.
*/
@Nonnegative
public int getRowDimension ()
{
return m_nRows;
}
/**
* Get column dimension.
*
* @return nCols, the number of columns.
*/
@Nonnegative
public int getColumnDimension ()
{
return m_nCols;
}
/**
* @return true if the matrix is symmetrical, meaning number of
* rows and columns is identical.
*/
public boolean isSymmetrical ()
{
return m_nRows == m_nCols;
}
/**
* Get a single element.
*
* @param nRow
* Row index.
* @param nCol
* Column index.
* @return A(nRow,nCol)
*/
public int get (@Nonnegative final int nRow, @Nonnegative final int nCol)
{
return m_aData[nRow][nCol];
}
/**
* Get a submatrix.
*
* @param nStartRowIndex
* Initial row index
* @param nEndRowIndex
* Final row index
* @param nStartColumnIndex
* Initial column index
* @param nEndColumnIndex
* Final column index
* @return Matrix(nStartRowIndex:nEndRowIndex,nStartColumnIndex:
* nEndColumnIndex )
* @exception ArrayIndexOutOfBoundsException
* Submatrix indices
*/
@Nonnull
@ReturnsMutableCopy
public MatrixInt getMatrix (@Nonnegative final int nStartRowIndex,
@Nonnegative final int nEndRowIndex,
@Nonnegative final int nStartColumnIndex,
@Nonnegative final int nEndColumnIndex)
{
final MatrixInt aNewMatrix = new MatrixInt (nEndRowIndex - nStartRowIndex + 1, nEndColumnIndex - nStartColumnIndex + 1);
final int [] [] aNewArray = aNewMatrix.internalGetArray ();
for (int nRow = nStartRowIndex; nRow <= nEndRowIndex; nRow++)
{
final int [] aSrcRow = m_aData[nRow];
final int [] aDstRow = aNewArray[nRow - nStartRowIndex];
for (int nCol = nStartColumnIndex; nCol <= nEndColumnIndex; nCol++)
aDstRow[nCol - nStartColumnIndex] = aSrcRow[nCol];
}
return aNewMatrix;
}
/**
* Get a submatrix.
*
* @param aRows
* Array of row indices.
* @param aCols
* Array of column indices.
* @return Matrix(aRows(:),aCols(:))
* @exception ArrayIndexOutOfBoundsException
* Submatrix indices
*/
@Nonnull
@ReturnsMutableCopy
public MatrixInt getMatrix (@Nonnull final int [] aRows, @Nonnull final int [] aCols)
{
final MatrixInt aNewMatrix = new MatrixInt (aRows.length, aCols.length);
final int [] [] aNewArray = aNewMatrix.internalGetArray ();
for (int nRow = 0; nRow < aRows.length; nRow++)
{
final int nRowIndex = aRows[nRow];
final int [] aSrcRow = m_aData[nRowIndex];
final int [] aDstRow = aNewArray[nRow];
for (int nCol = 0; nCol < aCols.length; nCol++)
aDstRow[nCol] = aSrcRow[aCols[nCol]];
}
return aNewMatrix;
}
/**
* Get a submatrix.
*
* @param nStartRowIndex
* Initial row index
* @param nEndRowIndex
* Final row index
* @param aCols
* Array of column indices.
* @return Matrix(nStartRowIndex:nEndRowIndex,aCols(:))
* @exception ArrayIndexOutOfBoundsException
* Submatrix indices
*/
@Nonnull
@ReturnsMutableCopy
public MatrixInt getMatrix (@Nonnegative final int nStartRowIndex, @Nonnegative final int nEndRowIndex, @Nonnull final int [] aCols)
{
final MatrixInt aNewMatrix = new MatrixInt (nEndRowIndex - nStartRowIndex + 1, aCols.length);
final int [] [] aNewArray = aNewMatrix.internalGetArray ();
for (int nCol = 0; nCol < aCols.length; nCol++)
{
final int nColIndex = aCols[nCol];
for (int nRow = nStartRowIndex; nRow <= nEndRowIndex; nRow++)
aNewArray[nRow - nStartRowIndex][nCol] = m_aData[nRow][nColIndex];
}
return aNewMatrix;
}
/**
* Get a submatrix.
*
* @param aRows
* Array of row indices.
* @param nStartColumnIndex
* Initial column index
* @param nEndColumnIndex
* Final column index
* @return Matrix(aRows(:),nStartColumnIndex:nEndColumnIndex)
* @exception ArrayIndexOutOfBoundsException
* Submatrix indices
*/
@Nonnull
@ReturnsMutableCopy
public MatrixInt getMatrix (@Nonnull final int [] aRows, @Nonnegative final int nStartColumnIndex, @Nonnegative final int nEndColumnIndex)
{
final MatrixInt aNewMatrix = new MatrixInt (aRows.length, nEndColumnIndex - nStartColumnIndex + 1);
final int [] [] aNewArray = aNewMatrix.internalGetArray ();
for (int nRow = 0; nRow < aRows.length; nRow++)
{
final int nRowIndex = aRows[nRow];
final int [] aSrcRow = m_aData[nRowIndex];
final int [] aDstRow = aNewArray[nRow];
for (int nCol = nStartColumnIndex; nCol <= nEndColumnIndex; nCol++)
aDstRow[nCol - nStartColumnIndex] = aSrcRow[nCol];
}
return aNewMatrix;
}
/**
* Set a single element.
*
* @param nRow
* Row index.
* @param nCol
* Column index.
* @param nValue
* A(nRow,nCol).
*/
public void set (@Nonnegative final int nRow, @Nonnegative final int nCol, final int nValue)
{
m_aData[nRow][nCol] = nValue;
}
/**
* Set a submatrix.
*
* @param nStartRowIndex
* Initial row index
* @param nEndRowIndex
* Final row index
* @param nStartColumnIndex
* Initial column index
* @param nEndColumnIndex
* Final column index
* @param aMatrix
* Matrix(nStartRowIndex:nEndRowIndex,nStartColumnIndex:nEndColumnIndex
* )
* @exception ArrayIndexOutOfBoundsException
* Submatrix indices
*/
public void setMatrix (@Nonnegative final int nStartRowIndex,
@Nonnegative final int nEndRowIndex,
@Nonnegative final int nStartColumnIndex,
@Nonnegative final int nEndColumnIndex,
@Nonnull final MatrixInt aMatrix)
{
for (int nRow = nStartRowIndex; nRow <= nEndRowIndex; nRow++)
{
final int [] aRow = m_aData[nRow];
for (int nCol = nStartColumnIndex; nCol <= nEndColumnIndex; nCol++)
aRow[nCol] = aMatrix.get (nRow - nStartRowIndex, nCol - nStartColumnIndex);
}
}
/**
* Set a submatrix.
*
* @param aRows
* Array of row indices.
* @param aCols
* Array of column indices.
* @param aMatrix
* Matrix(aRows(:),aCols(:))
* @exception ArrayIndexOutOfBoundsException
* Submatrix indices
*/
public void setMatrix (@Nonnull final int [] aRows, @Nonnull final int [] aCols, @Nonnull final MatrixInt aMatrix)
{
for (int nRow = 0; nRow < aRows.length; nRow++)
{
final int nRowIndex = aRows[nRow];
final int [] aRow = m_aData[nRowIndex];
for (int nCol = 0; nCol < aCols.length; nCol++)
aRow[aCols[nCol]] = aMatrix.get (nRow, nCol);
}
}
/**
* Set a submatrix.
*
* @param aRows
* Array of row indices.
* @param nStartColumnIndex
* Initial column index
* @param nEndColumnIndex
* Final column index
* @param aMatrix
* Matrix(aRows(:),nStartColumnIndex:nEndColumnIndex
* @exception ArrayIndexOutOfBoundsException
* Submatrix indices
*/
public void setMatrix (@Nonnull final int [] aRows,
@Nonnegative final int nStartColumnIndex,
@Nonnegative final int nEndColumnIndex,
@Nonnull final MatrixInt aMatrix)
{
for (int nRow = 0; nRow < aRows.length; nRow++)
{
final int nRowIndex = aRows[nRow];
final int [] aRow = m_aData[nRowIndex];
for (int nCol = nStartColumnIndex; nCol <= nEndColumnIndex; nCol++)
aRow[nCol] = aMatrix.get (nRow, nCol - nStartColumnIndex);
}
}
/**
* Set a submatrix.
*
* @param nStartRowIndex
* Initial row index
* @param nEndRowIndex
* Final row index
* @param aCols
* Array of column indices.
* @param aMatrix
* Matrix(nStartRowIndex:nEndRowIndex,aCols(:))
* @exception ArrayIndexOutOfBoundsException
* Submatrix indices
*/
public void setMatrix (@Nonnegative final int nStartRowIndex,
@Nonnegative final int nEndRowIndex,
@Nonnull final int [] aCols,
@Nonnull final MatrixInt aMatrix)
{
for (int nRow = nStartRowIndex; nRow <= nEndRowIndex; nRow++)
{
final int [] aRow = m_aData[nRow];
for (int nCol = 0; nCol < aCols.length; nCol++)
{
final int nColIndex = aCols[nCol];
aRow[nColIndex] = aMatrix.get (nRow - nStartRowIndex, nCol);
}
}
}
/**
* Matrix transpose.
*
* @return A'
*/
@Nonnull
@ReturnsMutableCopy
@CheckReturnValue
public MatrixInt transpose ()
{
final MatrixInt aNewMatrix = new MatrixInt (m_nCols, m_nRows);
final int [] [] aNewArray = aNewMatrix.internalGetArray ();
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aSrcRow = m_aData[nRow];
for (int nCol = 0; nCol < m_nCols; nCol++)
aNewArray[nCol][nRow] = aSrcRow[nCol];
}
return aNewMatrix;
}
/**
* One norm
*
* @return maximum column sum.
*/
public int norm1 ()
{
int nRet = 0;
for (int nCol = 0; nCol < m_nCols; nCol++)
{
int nSum = 0;
for (int nRow = 0; nRow < m_nRows; nRow++)
nSum += MathHelper.abs (m_aData[nRow][nCol]);
nRet = Math.max (nRet, nSum);
}
return nRet;
}
/**
* Infinity norm
*
* @return maximum row sum.
*/
public int normInf ()
{
int ret = 0;
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aRow = m_aData[nRow];
int nSum = 0;
for (int nCol = 0; nCol < m_nCols; nCol++)
nSum += MathHelper.abs (aRow[nCol]);
ret = Math.max (ret, nSum);
}
return ret;
}
/**
* Frobenius norm
*
* @return sqrt of sum of squares of all elements.
*/
public double normF ()
{
double f = 0;
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aRow = m_aData[nRow];
for (int nCol = 0; nCol < m_nCols; nCol++)
f = MathHelper.hypot (f, aRow[nCol]);
}
return f;
}
/**
* Unary minus
*
* @return -A
*/
@Nonnull
@ReturnsMutableCopy
public MatrixInt uminus ()
{
final MatrixInt aNewMatrix = new MatrixInt (m_nRows, m_nCols);
final int [] [] aNewArray = aNewMatrix.internalGetArray ();
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aSrcRow = m_aData[nRow];
final int [] aDstRow = aNewArray[nRow];
for (int nCol = 0; nCol < m_nCols; nCol++)
aDstRow[nCol] = -aSrcRow[nCol];
}
return aNewMatrix;
}
/**
* Check if size(A) == size(B)
*
* @param aMatrix
* MAtrix to check
*/
private void _checkMatrixDimensions (@Nonnull final MatrixInt aMatrix)
{
if (aMatrix.m_nRows != m_nRows)
throw new IllegalArgumentException ("Matrix row dimensions must agree.");
if (aMatrix.m_nCols != m_nCols)
throw new IllegalArgumentException ("Matrix column dimensions must agree.");
}
/**
* C = A + B
*
* @param aMatrix
* another matrix
* @return A + B
*/
@Nonnull
@ReturnsMutableCopy
public MatrixInt plus (@Nonnull final MatrixInt aMatrix)
{
_checkMatrixDimensions (aMatrix);
final MatrixInt aNewMatrix = new MatrixInt (m_nRows, m_nCols);
final int [] [] aNewArray = aNewMatrix.internalGetArray ();
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aSrcRow1 = m_aData[nRow];
final int [] aSrcRow2 = aMatrix.m_aData[nRow];
final int [] aDstRow = aNewArray[nRow];
for (int nCol = 0; nCol < m_nCols; nCol++)
aDstRow[nCol] = aSrcRow1[nCol] + aSrcRow2[nCol];
}
return aNewMatrix;
}
/**
* A = A + B
*
* @param aMatrix
* another matrix
* @return this
*/
@Nonnull
public MatrixInt plusEquals (@Nonnull final MatrixInt aMatrix)
{
_checkMatrixDimensions (aMatrix);
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aSrcRow = aMatrix.m_aData[nRow];
final int [] aDstRow = m_aData[nRow];
for (int nCol = 0; nCol < m_nCols; nCol++)
aDstRow[nCol] += aSrcRow[nCol];
}
return this;
}
/**
* C = A - B
*
* @param aMatrix
* another matrix
* @return A - B
*/
@Nonnull
@ReturnsMutableCopy
public MatrixInt minus (@Nonnull final MatrixInt aMatrix)
{
_checkMatrixDimensions (aMatrix);
final MatrixInt aNewMatrix = new MatrixInt (m_nRows, m_nCols);
final int [] [] aNewArray = aNewMatrix.internalGetArray ();
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aSrcRow1 = m_aData[nRow];
final int [] aSrcRow2 = aMatrix.m_aData[nRow];
final int [] aDstRow = aNewArray[nRow];
for (int nCol = 0; nCol < m_nCols; nCol++)
aDstRow[nCol] = aSrcRow1[nCol] - aSrcRow2[nCol];
}
return aNewMatrix;
}
/**
* A = A - B
*
* @param aMatrix
* another matrix
* @return this
*/
@Nonnull
public MatrixInt minusEquals (@Nonnull final MatrixInt aMatrix)
{
_checkMatrixDimensions (aMatrix);
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aSrcRow = aMatrix.m_aData[nRow];
final int [] aDstRow = m_aData[nRow];
for (int nCol = 0; nCol < m_nCols; nCol++)
aDstRow[nCol] -= aSrcRow[nCol];
}
return this;
}
/**
* Element-by-element multiplication, C = A.*B
*
* @param aMatrix
* another matrix
* @return A.*B
*/
@Nonnull
@ReturnsMutableCopy
public MatrixInt arrayTimes (@Nonnull final MatrixInt aMatrix)
{
_checkMatrixDimensions (aMatrix);
final MatrixInt aNewMatrix = new MatrixInt (m_nRows, m_nCols);
final int [] [] aNewArray = aNewMatrix.internalGetArray ();
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aSrcRow1 = m_aData[nRow];
final int [] aSrcRow2 = aMatrix.m_aData[nRow];
final int [] aDstRow = aNewArray[nRow];
for (int nCol = 0; nCol < m_nCols; nCol++)
aDstRow[nCol] = aSrcRow1[nCol] * aSrcRow2[nCol];
}
return aNewMatrix;
}
/**
* Element-by-element multiplication in place, A = A.*B
*
* @param aMatrix
* another matrix
* @return this
*/
@Nonnull
public MatrixInt arrayTimesEquals (@Nonnull final MatrixInt aMatrix)
{
_checkMatrixDimensions (aMatrix);
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aSrcRow = aMatrix.m_aData[nRow];
final int [] aDstRow = m_aData[nRow];
for (int nCol = 0; nCol < m_nCols; nCol++)
aDstRow[nCol] *= aSrcRow[nCol];
}
return this;
}
/**
* Element-by-element right division, C = A./B
*
* @param aMatrix
* another matrix
* @return A./B
*/
@Nonnull
@ReturnsMutableCopy
public MatrixInt arrayRightDivide (@Nonnull final MatrixInt aMatrix)
{
_checkMatrixDimensions (aMatrix);
final MatrixInt aNewMatrix = new MatrixInt (m_nRows, m_nCols);
final int [] [] aNewArray = aNewMatrix.internalGetArray ();
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aSrcRow1 = m_aData[nRow];
final int [] aSrcRow2 = aMatrix.m_aData[nRow];
final int [] aDstRow = aNewArray[nRow];
for (int nCol = 0; nCol < m_nCols; nCol++)
aDstRow[nCol] = aSrcRow1[nCol] / aSrcRow2[nCol];
}
return aNewMatrix;
}
/**
* Element-by-element right division in place, A = A./B
*
* @param aMatrix
* another matrix
* @return this
*/
@Nonnull
public MatrixInt arrayRightDivideEquals (@Nonnull final MatrixInt aMatrix)
{
_checkMatrixDimensions (aMatrix);
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aSrcRow = aMatrix.m_aData[nRow];
final int [] aDstRow = m_aData[nRow];
for (int nCol = 0; nCol < m_nCols; nCol++)
aDstRow[nCol] /= aSrcRow[nCol];
}
return this;
}
/**
* Element-by-element left division, C = B.\A
*
* @param aMatrix
* another matrix
* @return B.\A
*/
@Nonnull
@ReturnsMutableCopy
public MatrixInt arrayLeftDivide (@Nonnull final MatrixInt aMatrix)
{
_checkMatrixDimensions (aMatrix);
final MatrixInt aNewMatrix = new MatrixInt (m_nRows, m_nCols);
final int [] [] aNewArray = aNewMatrix.internalGetArray ();
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aSrcRow1 = aMatrix.m_aData[nRow];
final int [] aSrcRow2 = m_aData[nRow];
final int [] aDstRow = aNewArray[nRow];
for (int nCol = 0; nCol < m_nCols; nCol++)
aDstRow[nCol] = aSrcRow1[nCol] / aSrcRow2[nCol];
}
return aNewMatrix;
}
/**
* Element-by-element left division in place, A = B.\A
*
* @param aMatrix
* another matrix
* @return this
*/
@Nonnull
public MatrixInt arrayLeftDivideEquals (@Nonnull final MatrixInt aMatrix)
{
_checkMatrixDimensions (aMatrix);
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aSrcRow1 = aMatrix.m_aData[nRow];
final int [] aSrcRow2 = m_aData[nRow];
final int [] aDstRow = aSrcRow2;
for (int nCol = 0; nCol < m_nCols; nCol++)
aDstRow[nCol] = aSrcRow1[nCol] / aSrcRow2[nCol];
}
return this;
}
/**
* Multiply a matrix by a scalar, C = s*A
*
* @param s
* scalar
* @return s*A
*/
@Nonnull
@ReturnsMutableCopy
public MatrixInt times (final int s)
{
final MatrixInt aNewMatrix = new MatrixInt (m_nRows, m_nCols);
final int [] [] aNewArray = aNewMatrix.internalGetArray ();
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aSrcRow = m_aData[nRow];
final int [] aDstRow = aNewArray[nRow];
for (int nCol = 0; nCol < m_nCols; nCol++)
aDstRow[nCol] = s * aSrcRow[nCol];
}
return aNewMatrix;
}
/**
* Multiply a matrix by a scalar in place, A = s*A
*
* @param s
* scalar
* @return this
*/
@Nonnull
public MatrixInt timesEquals (final double s)
{
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aDstRow = m_aData[nRow];
for (int nCol = 0; nCol < m_nCols; nCol++)
aDstRow[nCol] = (int) (aDstRow[nCol] * s);
}
return this;
}
/**
* Linear algebraic matrix multiplication, A * B
*
* @param aMatrix
* another matrix
* @return Matrix product, A * B
* @exception IllegalArgumentException
* Matrix inner dimensions must agree.
*/
@Nonnull
@ReturnsMutableCopy
public MatrixInt times (@Nonnull final MatrixInt aMatrix)
{
if (aMatrix.m_nRows != m_nCols)
throw new IllegalArgumentException ("Matrix inner dimensions must agree.");
final MatrixInt aNewMatrix = new MatrixInt (m_nRows, aMatrix.m_nCols);
final int [] [] aNewArray = aNewMatrix.internalGetArray ();
final int [] aRhsCol = new int [m_nCols];
for (int nCol = 0; nCol < aMatrix.m_nCols; nCol++)
{
for (int k = 0; k < m_nCols; k++)
aRhsCol[k] = aMatrix.m_aData[k][nCol];
for (int nRow = 0; nRow < m_nRows; nRow++)
{
final int [] aRow = m_aData[nRow];
// Build and assign sum
int nValue = 0;
for (int k = 0; k < m_nCols; k++)
nValue += aRow[k] * aRhsCol[k];
aNewArray[nRow][nCol] = nValue;
}
}
return aNewMatrix;
}
/**
* Matrix trace.
*
* @return sum of the diagonal elements.
*/
public int trace ()
{
int t = 0;
final int nMin = Math.min (m_nRows, m_nCols);
for (int nIndex = 0; nIndex < nMin; nIndex++)
t += m_aData[nIndex][nIndex];
return t;
}
/**
* Generate matrix with random elements
*
* @param nRows
* Number of rows.
* @param nCols
* Number of columns.
* @return An nRows-by-nCols matrix with uniformly distributed random
* elements.
*/
@Nonnull
@ReturnsMutableCopy
public static MatrixInt random (@Nonnegative final int nRows, @Nonnegative final int nCols)
{
final Random aRandom = ThreadLocalRandom.current ();
final MatrixInt aNewMatrix = new MatrixInt (nRows, nCols);
final int [] [] aNewArray = aNewMatrix.internalGetArray ();
for (int nRow = 0; nRow < nRows; nRow++)
{
final int [] aDstRow = aNewArray[nRow];
for (int nCol = 0; nCol < nCols; nCol++)
aDstRow[nCol] = 1 + aRandom.nextInt (100);
}
return aNewMatrix;
}
/**
* Generate identity matrix
*
* @param nRows
* Number of rows.
* @param nCols
* Number of columns.
* @return An nRows-by-nCols matrix with ones on the diagonal and zeros
* elsewhere.
*/
@Nonnull
@ReturnsMutableCopy
public static MatrixInt identity (@Nonnegative final int nRows, @Nonnegative final int nCols)
{
final MatrixInt aNewMatrix = new MatrixInt (nRows, nCols);
final int [] [] aNewArray = aNewMatrix.internalGetArray ();
for (int nRow = 0; nRow < nRows; nRow++)
{
final int [] aRow = aNewArray[nRow];
for (int nCol = 0; nCol < nCols; nCol++)
aRow[nCol] = (nRow == nCol ? 1 : 0);
}
return aNewMatrix;
}
/**
* Print the matrix to the output stream. Line the elements up in columns with
* a Fortran-like 'Fw.d' style format.
*
* @param aPW
* Output stream.
* @param nWidth
* Column width.
* @param nFractionDigits
* Number of digits after the decimal.
*/
public void print (@Nonnull final PrintWriter aPW, @Nonnegative final int nWidth, @Nonnegative final int nFractionDigits)
{
final NumberFormat format = NumberFormat.getInstance (Locale.US);
format.setMinimumIntegerDigits (1);
format.setMaximumFractionDigits (nFractionDigits);
format.setMinimumFractionDigits (nFractionDigits);
format.setGroupingUsed (false);
print (aPW, format, nWidth + 2);
}
// DecimalFormat is a little disappointing coming from Fortran or C's printf.
// Since it doesn't pad on the left, the elements will come out different
// widths. Consequently, we'll pass the desired column width in as an
// argument and do the extra padding ourselves.
/**
* Print the matrix to the output stream. Line the elements up in columns. Use
* the format object, and right justify within columns of width characters.
* Note that is the matrix is to be read back in, you probably will want to
* use a NumberFormat that is set to US Locale.
*
* @param aPW
* the output stream.
* @param aFormat
* A formatting object to format the matrix elements
* @param nWidth
* Column width.
* @see java.text.DecimalFormat#setDecimalFormatSymbols
*/
public void print (@Nonnull final PrintWriter aPW, @Nonnull final NumberFormat aFormat, @Nonnegative final int nWidth)
{
aPW.println (); // start on new line.
for (int nRow = 0; nRow < m_nRows; nRow++)
{
for (int nCol = 0; nCol < m_nCols; nCol++)
{
// format the number
final String s = aFormat.format (m_aData[nRow][nCol]);
// At _least_ 1 space
final int padding = Math.max (1, nWidth - s.length ());
aPW.print (StringHelper.getRepeated (' ', padding));
aPW.print (s);
}
aPW.println ();
}
// end with blank line.
aPW.println ();
}
@Override
public boolean equals (final Object o)
{
if (o == this)
return true;
if (o == null || !getClass ().equals (o.getClass ()))
return false;
final MatrixInt rhs = (MatrixInt) o;
if (m_nRows != rhs.m_nRows || m_nCols != rhs.m_nCols)
return false;
for (int nRow = 0; nRow < m_nRows; ++nRow)
if (!Arrays.equals (m_aData[nRow], rhs.m_aData[nRow]))
return false;
return true;
}
@Override
public int hashCode ()
{
final HashCodeGenerator aHC = new HashCodeGenerator (this).append (m_nRows).append (m_nCols);
for (int nRow = 0; nRow < m_nRows; ++nRow)
aHC.append (m_aData[nRow]);
return aHC.getHashCode ();
}
/**
* Read a matrix from a stream. The format is the same the print method, so
* printed matrices can be read back in (provided they were printed using US
* Locale). Elements are separated by whitespace, all the elements for each
* row appear on a single line, the last row is followed by a blank line.
*
* @param aReader
* the input stream.
* @return The read matrix
* @throws IOException
* in case of an I/O error
*/
@Nonnull
public static MatrixInt read (@Nonnull @WillNotClose final Reader aReader) throws IOException
{
final StreamTokenizer aTokenizer = new StreamTokenizer (StreamHelper.getBuffered (aReader));
// Although StreamTokenizer will parse numbers, it doesn't recognize
// scientific notation (E or D); however, Double.valueOf does.
// The strategy here is to disable StreamTokenizer's number parsing.
// We'll only get whitespace delimited words, EOL's and EOF's.
// These words should all be numbers, for Double.valueOf to parse.
aTokenizer.resetSyntax ();
aTokenizer.wordChars (0, 255);
aTokenizer.whitespaceChars (0, ' ');
aTokenizer.eolIsSignificant (true);
// Ignore initial empty lines
while (aTokenizer.nextToken () == StreamTokenizer.TT_EOL)
{
// Skip all new lines
}
if (aTokenizer.ttype == StreamTokenizer.TT_EOF)
throw new IOException ("Unexpected EOF on matrix read.");
// Read & store 1st row.
final ICommonsList vD = new CommonsArrayList <> ();
do
{
vD.add (Integer.valueOf (Integer.parseInt (aTokenizer.sval)));
} while (aTokenizer.nextToken () == StreamTokenizer.TT_WORD);
// Now we've got the number of columns!
final int nCols = vD.size ();
int [] aRow = new int [nCols];
for (int nCol = 0; nCol < nCols; nCol++)
{
// extract the elements of the 1st row.
aRow[nCol] = vD.get (nCol).intValue ();
}
final ICommonsList v = new CommonsArrayList <> ();
// Start storing rows instead of columns.
v.add (aRow);
while (aTokenizer.nextToken () == StreamTokenizer.TT_WORD)
{
// While non-empty lines
aRow = new int [nCols];
v.add (aRow);
int nCol = 0;
do
{
if (nCol >= nCols)
throw new IOException ("Row " + v.size () + " is too long.");
aRow[nCol++] = Integer.parseInt (aTokenizer.sval);
} while (aTokenizer.nextToken () == StreamTokenizer.TT_WORD);
if (nCol < nCols)
throw new IOException ("Row " + v.size () + " is too short.");
}
// Now we've got the number of rows.
final int nRows = v.size ();
// copy the rows out of the vector
return new MatrixInt (v.toArray (new int [nRows] []));
}
}