public class DenseDoubleMatrix2D extends DoubleMatrix2D
Implementation:
Internally holds one single contigous one-dimensional array, addressed in row major. Note that this implementation is not synchronized.
Memory requirements:
memory [bytes] = 8*rows()*columns(). Thus, a 1000*1000 matrix uses 8 MB.
Time complexity:
O(1) (i.e. constant time) for the basic operations get, getQuick, set, setQuick and size,
Cells are internally addressed in row-major. Applications demanding utmost speed can exploit this fact. Setting/getting values in a loop row-by-row is quicker than column-by-column. Thus
for (int row=0; row < rows; row++) {
for (int column=0; column < columns; column++) {
matrix.setQuick(row,column,someValue);
}
}
is quicker than
for (int column=0; column < columns; column++) {
for (int row=0; row < rows; row++) {
matrix.setQuick(row,column,someValue);
}
}
| Modifier and Type | Field and Description |
|---|---|
protected double[] |
elements
The elements of this matrix.
|
columns, columnStride, columnZero, rows, rowStride, rowZeroisNoView| Modifier | Constructor and Description |
|---|---|
|
DenseDoubleMatrix2D(double[][] values)
Constructs a matrix with a copy of the given values.
|
|
DenseDoubleMatrix2D(int rows,
int columns)
Constructs a matrix with a given number of rows and columns.
|
protected |
DenseDoubleMatrix2D(int rows,
int columns,
double[] elements,
int rowZero,
int columnZero,
int rowStride,
int columnStride)
Constructs a view with the given parameters.
|
| Modifier and Type | Method and Description |
|---|---|
DoubleMatrix2D |
assign(double value)
Sets all cells to the state specified by value.
|
DoubleMatrix2D |
assign(double[][] values)
Sets all cells to the state specified by values.
|
DoubleMatrix2D |
assign(DoubleFunction function)
Assigns the result of a function to each cell; x[row,col] = function(x[row,col]).
|
DoubleMatrix2D |
assign(DoubleMatrix2D source)
Replaces all cell values of the receiver with the values of another matrix.
|
DoubleMatrix2D |
assign(DoubleMatrix2D y,
DoubleDoubleFunction function)
Assigns the result of a function to each cell; x[row,col] = function(x[row,col],y[row,col]).
|
double |
getQuick(int row,
int column)
Returns the matrix cell value at coordinate [row,column].
|
protected boolean |
haveSharedCellsRaw(DoubleMatrix2D other)
Returns true if both matrices share common cells.
|
protected int |
index(int row,
int column)
Returns the position of the given coordinate within the (virtual or non-virtual) internal 1-dimensional array.
|
DoubleMatrix2D |
like(int rows,
int columns)
Construct and returns a new empty matrix of the same dynamic type as the receiver, having the specified number of rows and columns.
|
DoubleMatrix1D |
like1D(int size)
Construct and returns a new 1-d matrix of the corresponding dynamic type, entirelly independent of the receiver.
|
protected DoubleMatrix1D |
like1D(int size,
int zero,
int stride)
Construct and returns a new 1-d matrix of the corresponding dynamic type, sharing the same cells.
|
void |
setQuick(int row,
int column,
double value)
Sets the matrix cell at coordinate [row,column] to the specified value.
|
protected DoubleMatrix2D |
viewSelectionLike(int[] rowOffsets,
int[] columnOffsets)
Construct and returns a new selection view.
|
void |
zAssign8Neighbors(DoubleMatrix2D B,
Double9Function function)
8 neighbor stencil transformation.
|
DoubleMatrix1D |
zMult(DoubleMatrix1D y,
DoubleMatrix1D z,
double alpha,
double beta,
boolean transposeA)
Linear algebraic matrix-vector multiplication; z = alpha * A * y + beta*z.
|
DoubleMatrix2D |
zMult(DoubleMatrix2D B,
DoubleMatrix2D C,
double alpha,
double beta,
boolean transposeA,
boolean transposeB)
Linear algebraic matrix-matrix multiplication; C = alpha * A x B + beta*C.
|
double |
zSum()
Returns the sum of all cells; Sum( x[i,j] ).
|
aggregate, aggregate, cardinality, copy, equals, equals, forEachNonZero, get, getContent, getNonZeros, haveSharedCells, like, set, toArray, toString, view, viewColumn, viewColumnFlip, viewDice, viewPart, viewRow, viewRowFlip, viewSelection, viewSelection, viewSorted, viewStrides, zMult, zMult_columnOffset, _columnRank, _rowOffset, _rowRank, checkBox, checkColumn, checkColumnIndexes, checkRow, checkRowIndexes, checkShape, checkShape, columns, rows, setUp, setUp, size, toStringShort, vColumnFlip, vDice, vPart, vRowFlip, vStridesensureCapacity, isView, trimToSizecloneprotected double[] elements
public DenseDoubleMatrix2D(double[][] values)
The values are copied. So subsequent changes in values are not reflected in the matrix, and vice-versa.
values - The values to be filled into the new matrix.IllegalArgumentException - if for any 1 <= row < values.length: values[row].length != values[row-1].length.public DenseDoubleMatrix2D(int rows,
int columns)
rows - the number of rows the matrix shall have.columns - the number of columns the matrix shall have.IllegalArgumentException - if rows<0 || columns<0 || (double)columns*rows > Integer.MAX_VALUE.protected DenseDoubleMatrix2D(int rows,
int columns,
double[] elements,
int rowZero,
int columnZero,
int rowStride,
int columnStride)
rows - the number of rows the matrix shall have.columns - the number of columns the matrix shall have.elements - the cells.rowZero - the position of the first element.columnZero - the position of the first element.rowStride - the number of elements between two rows, i.e. index(i+1,j)-index(i,j).columnStride - the number of elements between two columns, i.e. index(i,j+1)-index(i,j).IllegalArgumentException - if rows<0 || columns<0 || (double)columns*rows > Integer.MAX_VALUE or flip's are illegal.public DoubleMatrix2D assign(double[][] values)
The values are copied. So subsequent changes in values are not reflected in the matrix, and vice-versa.
assign in class DoubleMatrix2Dvalues - the values to be filled into the cells.IllegalArgumentException - if values.length != rows() || for any 0 <= row < rows(): values[row].length != columns().public DoubleMatrix2D assign(double value)
assign in class DoubleMatrix2Dvalue - the value to be filled into the cells.public DoubleMatrix2D assign(DoubleFunction function)
Example:
matrix = 2 x 2 matrix 0.5 1.5 2.5 3.5 // change each cell to its sine matrix.assign(cern.jet.math.Functions.sin); --> 2 x 2 matrix 0.479426 0.997495 0.598472 -0.350783For further examples, see the package doc.
assign in class DoubleMatrix2Dfunction - a function object taking as argument the current cell's value.Functionspublic DoubleMatrix2D assign(DoubleMatrix2D source)
assign in class DoubleMatrix2Dsource - the source matrix to copy from (may be identical to the receiver).IllegalArgumentException - if columns() != source.columns() || rows() != source.rows()public DoubleMatrix2D assign(DoubleMatrix2D y, DoubleDoubleFunction function)
Example:
// assign x[row,col] = x[row,col]y[row,col] m1 = 2 x 2 matrix 0 1 2 3 m2 = 2 x 2 matrix 0 2 4 6 m1.assign(m2, cern.jet.math.Functions.pow); --> m1 == 2 x 2 matrix 1 1 16 729For further examples, see the package doc.
assign in class DoubleMatrix2Dy - the secondary matrix to operate on.function - a function object taking as first argument the current cell's value of this,
and as second argument the current cell's value of y,IllegalArgumentException - if columns() != other.columns() || rows() != other.rows()Functionspublic double getQuick(int row,
int column)
Provided with invalid parameters this method may return invalid objects without throwing any exception. You should only use this method when you are absolutely sure that the coordinate is within bounds. Precondition (unchecked): 0 <= column < columns() && 0 <= row < rows().
getQuick in class DoubleMatrix2Drow - the index of the row-coordinate.column - the index of the column-coordinate.protected boolean haveSharedCellsRaw(DoubleMatrix2D other)
haveSharedCellsRaw in class DoubleMatrix2Dprotected int index(int row,
int column)
index in class AbstractMatrix2Drow - the index of the row-coordinate.column - the index of the column-coordinate.public DoubleMatrix2D like(int rows, int columns)
like in class DoubleMatrix2Drows - the number of rows the matrix shall have.columns - the number of columns the matrix shall have.public DoubleMatrix1D like1D(int size)
like1D in class DoubleMatrix2Dsize - the number of cells the matrix shall have.protected DoubleMatrix1D like1D(int size, int zero, int stride)
like1D in class DoubleMatrix2Dsize - the number of cells the matrix shall have.zero - the index of the first element.stride - the number of indexes between any two elements, i.e. index(i+1)-index(i).public void setQuick(int row,
int column,
double value)
Provided with invalid parameters this method may access illegal indexes without throwing any exception. You should only use this method when you are absolutely sure that the coordinate is within bounds. Precondition (unchecked): 0 <= column < columns() && 0 <= row < rows().
setQuick in class DoubleMatrix2Drow - the index of the row-coordinate.column - the index of the column-coordinate.value - the value to be filled into the specified cell.protected DoubleMatrix2D viewSelectionLike(int[] rowOffsets, int[] columnOffsets)
viewSelectionLike in class DoubleMatrix2DrowOffsets - the offsets of the visible elements.columnOffsets - the offsets of the visible elements.public void zAssign8Neighbors(DoubleMatrix2D B, Double9Function function)
B[i,j] = function.apply( A[i-1,j-1], A[i-1,j], A[i-1,j+1], A[i, j-1], A[i, j], A[i, j+1], A[i+1,j-1], A[i+1,j], A[i+1,j+1] ) x x x - - x x x - - - - x o x - - x o x - - - - x x x - - x x x ... - x x x - - - - - - - - - x o x - - - - - - - - - x x xMake sure that cells of this and B do not overlap. In case of overlapping views, behaviour is unspecified.
Example:
final double alpha = 0.25;
final double beta = 0.75;
// 8 neighbors
cern.colt.function.Double9Function f = new cern.colt.function.Double9Function() {
public final double apply(
double a00, double a01, double a02,
double a10, double a11, double a12,
double a20, double a21, double a22) {
return beta*a11 + alpha*(a00+a01+a02 + a10+a12 + a20+a21+a22);
}
};
A.zAssign8Neighbors(B,f);
// 4 neighbors
cern.colt.function.Double9Function g = new cern.colt.function.Double9Function() {
public final double apply(
double a00, double a01, double a02,
double a10, double a11, double a12,
double a20, double a21, double a22) {
return beta*a11 + alpha*(a01+a10+a12+a21);
}
C.zAssign8Neighbors(B,g); // fast, even though it doesn't look like it
};
zAssign8Neighbors in class DoubleMatrix2DB - the matrix to hold the results.function - the function to be applied to the 9 cells.NullPointerException - if function==null.IllegalArgumentException - if rows() != B.rows() || columns() != B.columns().public DoubleMatrix1D zMult(DoubleMatrix1D y, DoubleMatrix1D z, double alpha, double beta, boolean transposeA)
DoubleMatrix2DzMult in class DoubleMatrix2Dy - the source vector.z - the vector where results are to be stored. Set this parameter to null to indicate that a new result vector shall be constructed.public DoubleMatrix2D zMult(DoubleMatrix2D B, DoubleMatrix2D C, double alpha, double beta, boolean transposeA, boolean transposeB)
DoubleMatrix2DzMult in class DoubleMatrix2DB - the second source matrix.C - the matrix where results are to be stored. Set this parameter to null to indicate that a new result matrix shall be constructed.public double zSum()
zSum in class DoubleMatrix2DCopyright © 2006–2019 SYSTAP, LLC DBA Blazegraph. All rights reserved.