org.ejml.data.FMatrixD1 Maven / Gradle / Ivy
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/*
* Copyright (c) 2009-2017, Peter Abeles. All Rights Reserved.
*
* This file is part of Efficient Java Matrix Library (EJML).
*
* 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 org.ejml.data;
/**
* A generic abstract class for matrices whose data is stored in a single 1D array of floats. The
* format of the elements in this array is not specified. For example row major, column major,
* and block row major are all common formats.
*
* @author Peter Abeles
*/
public abstract class FMatrixD1 implements ReshapeMatrix, FMatrix {
/**
* Where the raw data for the matrix is stored. The format is type dependent.
*/
public float[] data;
/**
* Number of rows in the matrix.
*/
public int numRows;
/**
* Number of columns in the matrix.
*/
public int numCols;
/**
* Used to get a reference to the internal data.
*
* @return Reference to the matrix's data.
*/
public float[] getData() {
return data;
}
/**
* Changes the internal array reference.
*/
public void setData( float[] data ) {
this.data = data;
}
/**
* Returns the internal array index for the specified row and column.
*
* @param row Row index.
* @param col Column index.
* @return Internal array index.
*/
public abstract int getIndex( int row, int col );
/**
* Sets the value of this matrix to be the same as the value of the provided matrix. Both
* matrices must have the same shape:
*
* aij = bij
*
*
* @param b The matrix that this matrix is to be set equal to.
*/
public void set( FMatrixD1 b )
{
this.reshape(b.numRows,b.numCols);
int dataLength = b.getNumElements();
System.arraycopy(b.data, 0, this.data, 0, dataLength);
}
/**
* Returns the value of the matrix at the specified internal array index. The element at which row and column
* returned by this function depends upon the matrix's internal structure, e.g. row-major, column-major, or block.
*
* @param index Internal array index.
* @return Value at the specified index.
*/
public float get( int index ) {
return data[index];
}
/**
* Sets the element's value at the specified index. The element at which row and column
* modified by this function depends upon the matrix's internal structure, e.g. row-major, column-major, or block.
*
* @param index Index of element that is to be set.
* @param val The new value of the index.
*/
public float set( int index , float val ) {
// See benchmarkFunctionReturn. Pointless return does not degrade performance. Tested on JDK 1.6f.0_21
return data[index] = val;
}
/**
*
* Adds the specified value to the internal data array at the specified index.
*
* Equivalent to: this.data[index] += val;
*
*
*
* Intended for use in highly optimized code. The row/column coordinate of the modified element is
* dependent upon the matrix's internal structure.
*
*
* @param index The index which is being modified.
* @param val The value that is being added.
*/
public float plus( int index , float val ) {
// See benchmarkFunctionReturn. Pointless return does not degrade performance. Tested on JDK 1.6f.0_21
return data[index] += val;
}
/**
*
* Subtracts the specified value to the internal data array at the specified index.
*
* Equivalent to: this.data[index] -= val;
*
*
*
* Intended for use in highly optimized code. The row/column coordinate of the modified element is
* dependent upon the matrix's internal structure.
*
*
* @param index The index which is being modified.
* @param val The value that is being subtracted.
*/
public float minus( int index , float val ) {
// See benchmarkFunctionReturn. Pointless return does not degrade performance. Tested on JDK 1.6f.0_21
return data[index] -= val;
}
/**
*
* Multiplies the specified value to the internal data array at the specified index.
*
* Equivalent to: this.data[index] *= val;
*
*
*
* Intended for use in highly optimized code. The row/column coordinate of the modified element is
* dependent upon the matrix's internal structure.
*
*
* @param index The index which is being modified.
* @param val The value that is being multiplied.
*/
public float times( int index , float val ) {
// See benchmarkFunctionReturn. Pointless return does not degrade performance. Tested on JDK 1.6f.0_21
return data[index] *= val;
}
/**
*
* Divides the specified value to the internal data array at the specified index.
*
* Equivalent to: this.data[index] /= val;
*
*
*
* Intended for use in highly optimized code. The row/column coordinate of the modified element is
* dependent upon the matrix's internal structure.
*
*
* @param index The index which is being modified.
* @param val The value that is being divided.
*/
public float div( int index , float val ) {
// See benchmarkFunctionReturn. Pointless return does not degrade performance. Tested on JDK 1.6f.0_21
return data[index] /= val;
}
/**
*
* Changes the number of rows and columns in the matrix, allowing its size to grow or shrink.
* If the saveValues flag is set to true, then the previous values will be maintained, but
* reassigned to new elements in a row-major ordering. If saveValues is false values will only
* be maintained when the requested size is less than or equal to the internal array size.
* The primary use for this function is to encourage data reuse and avoid unnecessarily declaring
* and initialization of new memory.
*
*
*
* Examples:
* [ 1 2 ; 3 4 ] → reshape( 2 , 3 , true ) = [ 1 2 3 ; 4 0 0 ]
* [ 1 2 ; 3 4 ] → reshape( 1 , 2 , true ) = [ 1 2 ]
* [ 1 2 ; 3 4 ] → reshape( 1 , 2 , false ) = [ 1 2 ]
* [ 1 2 ; 3 4 ] → reshape( 2 , 3 , false ) = [ 0 0 0 ; 0 0 0 ]
*
*
* @param numRows The new number of rows in the matrix.
* @param numCols The new number of columns in the matrix.
* @param saveValues If true then the value of each element will be save using a row-major reordering. Typically this should be false.
*/
public abstract void reshape(int numRows, int numCols, boolean saveValues);
/**
* Equivalent to invoking reshape(numRows,numCols,false);
*
* @param numRows The new number of rows in the matrix.
* @param numCols The new number of columns in the matrix.
*/
@Override
public void reshape( int numRows , int numCols ) {
reshape(numRows,numCols,false);
}
/**
* Creates a new iterator for traversing through a submatrix inside this matrix. It can be traversed
* by row or by column. Range of elements is inclusive, e.g. minRow = 0 and maxRow = 1 will include rows
* 0 and 1. The iteration starts at (minRow,minCol) and ends at (maxRow,maxCol)
*
* @param rowMajor true means it will traverse through the submatrix by row first, false by columns.
* @param minRow first row it will start at.
* @param minCol first column it will start at.
* @param maxRow last row it will stop at.
* @param maxCol last column it will stop at.
* @return A new MatrixIterator
*/
public FMatrixIterator iterator(boolean rowMajor, int minRow, int minCol, int maxRow, int maxCol)
{
return new FMatrixIterator(this,rowMajor, minRow, minCol, maxRow, maxCol);
}
/**
* {@inheritDoc}
*/
@Override
public int getNumRows() {
return numRows;
}
/**
* {@inheritDoc}
*/
@Override
public int getNumCols() {
return numCols;
}
/**
* Sets the number of rows.
*
* @param numRows Number of rows
*/
public void setNumRows(int numRows) {
this.numRows = numRows;
}
/**
* Sets the number of columns.
*
* @param numCols Number of columns
*/
public void setNumCols(int numCols) {
this.numCols = numCols;
}
}