/// <summary>
/// Constructs a diagonal block matrix from the given parts.
/// </summary>
/// <param name="a">
/// The matrix A.
/// </param>
/// <param name="b">
/// The matrix B.
/// </param>
/// <param name="c">
/// The matrix C.
/// </param>
/// <returns>
/// A diagonal block matrix.
/// </returns>
public DoubleMatrix2D ComposeDiagonal(DoubleMatrix2D a, DoubleMatrix2D b, DoubleMatrix2D c)
{
DoubleMatrix2D diag = Make(a.Rows + b.Rows + c.Rows, a.Columns + b.Columns + c.Columns);
diag.ViewPart(0, 0, a.Rows, a.Columns).Assign(a);
diag.ViewPart(a.Rows, a.Columns, b.Rows, b.Columns).Assign(b);
diag.ViewPart(a.Rows + b.Rows, a.Columns + b.Columns, c.Rows, c.Columns).Assign(c);
return(diag);
}
/// <summary>
/// Constructs an identity matrix (having ones on the diagonal and zeros elsewhere).
/// </summary>
/// <param name="rowsAndColumns">
/// The rows and columns.
/// </param>
/// <returns>
/// An identity matrix.
/// </returns>
public DoubleMatrix2D Identity(int rowsAndColumns)
{
DoubleMatrix2D matrix = Make(rowsAndColumns, rowsAndColumns);
for (int i = rowsAndColumns; --i >= 0;)
{
matrix[i, i] = 1;
}
return(matrix);
}
/// <summary>
/// Constructs a new vector consisting of the diagonal elements of <tt>A</tt>.
/// Cells values are copied. The new vector is not a view.
/// </summary>
/// <param name="a">
/// The amatrix, need not be square.
/// </param>
/// <returns>
/// A new vector.
/// </returns>
public DoubleMatrix1D Diagonal(DoubleMatrix2D a)
{
int min = Math.Min(a.Rows, a.Columns);
DoubleMatrix1D diag = make1D(min);
for (int i = min; --i >= 0;)
{
diag[i] = a[i, i];
}
return(diag);
}
/// <summary>
/// Constructs a new diagonal matrix whose diagonal elements are the elements of <tt>vector</tt>.
/// Cells values are copied. The new matrix is not a view.
/// </summary>
/// <param name="vector">
/// The vector.
/// </param>
/// <returns>
/// A new matrix.
/// </returns>
public DoubleMatrix2D Diagonal(DoubleMatrix1D vector)
{
int size = vector.Size;
DoubleMatrix2D diag = Make(size, size);
for (int i = size; --i >= 0;)
{
diag[i, i] = vector[i];
}
return(diag);
}
/// <summary>
/// Constructs a diagonal block matrix from the given parts (the <i>direct sum</i> of two matrices).
/// </summary>
/// <param name="a">
/// The matrix A.
/// </param>
/// <param name="b">
/// The matrix B.
/// </param>
/// <returns>
/// A diagonal block matrix.
/// </returns>
public DoubleMatrix2D ComposeDiagonal(DoubleMatrix2D a, DoubleMatrix2D b)
{
int ar = a.Rows;
int ac = a.Columns;
int br = b.Rows;
int bc = b.Columns;
DoubleMatrix2D sum = Make(ar + br, ac + bc);
sum.ViewPart(0, 0, ar, ac).Assign(a);
sum.ViewPart(ar, ac, br, bc).Assign(b);
return(sum);
}
/// <summary>
/// Returns <tt>true</tt> if both matrices share at least one identical cell.
/// </summary>
/// <param name="other">
/// The other matrix.
/// </param>
/// <returns>
/// <tt>true</tt> if both matrices share at least one identical cell.
/// </returns>
protected bool HaveSharedCells(DoubleMatrix2D other)
{
if (other == null)
{
return(false);
}
if (this == other)
{
return(true);
}
return(GetContent().HaveSharedCellsRaw(other.GetContent()));
}
/// <summary>
/// Assigns the result of a function to each cell; <tt>x[row,col] = function(x[row,col],y[row,col])</tt>.
/// </summary>
/// <param name="y">
/// The secondary matrix to operate on.
/// </param>
/// <param name="function">
/// The function taking as first argument the current cell's value of <tt>this</tt>,
/// and as second argument the current cell's value of <tt>y</tt>.
/// </param>
/// <returns>
/// <tt>this</tt> (for convenience only).
/// </returns>
/// <exception cref="ArgumentException">
/// If <tt>columns() != other.columns() || rows() != other.rows()</tt>
/// </exception>
public virtual DoubleMatrix2D Assign(DoubleMatrix2D y, DoubleDoubleFunction function)
{
CheckShape(y);
for (int row = Rows; --row >= 0;)
{
for (int column = Columns; --column >= 0;)
{
this[row, column] = function(this[row, column], y[row, column]);
}
}
return(this);
}
/// <summary>
/// Constructs a matrix with cells having descending values.
/// For debugging purposes.
/// </summary>
/// <param name="rows">
/// The number of rows.
/// </param>
/// <param name="columns">
/// The number of columns.
/// </param>
/// <returns>
/// A matrix with cells having descending values.
/// </returns>
public DoubleMatrix2D Descending(int rows, int columns)
{
DoubleMatrix2D matrix = Make(rows, columns);
int v = 0;
for (int row = rows; --row >= 0;)
{
for (int column = columns; --column >= 0;)
{
matrix[row, column] = v++;
}
}
return(matrix);
}
/// <summary>
/// Constructs a new matrix which is duplicated both along the row and column dimension.
/// </summary>
/// <param name="a">
/// The matrix to duplicate.
/// </param>
/// <param name="rowRepeat">
/// The number of row repetitions.
/// </param>
/// <param name="columnRepeat">
/// The number of column repetitions.
/// </param>
/// <returns>
/// A matrix.
/// </returns>
public DoubleMatrix2D Repeat(DoubleMatrix2D a, int rowRepeat, int columnRepeat)
{
int r = a.Rows;
int c = a.Columns;
DoubleMatrix2D matrix = Make(r * rowRepeat, c * columnRepeat);
for (int i = rowRepeat; --i >= 0;)
{
for (int j = columnRepeat; --j >= 0;)
{
matrix.ViewPart(r * i, c * j, r, c).Assign(a);
}
}
return(matrix);
}
/// <summary>
/// Linear algebraic matrix-matrix multiplication; <tt>C = alpha * A x B + beta*C</tt>.
/// </summary>
/// <param name="b">
/// The second source matrix.
/// </param>
/// <param name="c">
/// The matrix where results are to be storedd Set this parameter to <tt>null</tt> to indicate that a new result matrix shall be constructed.
/// </param>
/// <param name="alpha">
/// The alpha.
/// </param>
/// <param name="beta">
/// The beta.
/// </param>
/// <param name="transposeA">
/// Whether A must be transposed.
/// </param>
/// <param name="transposeB">
/// Whether B must be transposed.
/// </param>
/// <returns>
/// C (for convenience only).
/// </returns>
/// <exception cref="ArgumentOutOfRangeException">
/// If <tt>B.rows() != A.columns()</tt>.
/// </exception>
/// <exception cref="ArgumentException">
/// If <tt>C.rows() != A.rows() || C.columns() != B.columns()</tt>.
/// </exception>
/// <exception cref="ArithmeticException">
/// If <tt>A == C || B == C</tt>.
/// </exception>
public virtual DoubleMatrix2D ZMult(DoubleMatrix2D b, DoubleMatrix2D c, double alpha, double beta, bool transposeA, bool transposeB)
{
if (transposeA)
{
return(ViewDice().ZMult(b, c, alpha, beta, false, transposeB));
}
if (transposeB)
{
return(ZMult(b.ViewDice(), c, alpha, beta, false, false));
}
int m = Rows;
int n = Columns;
int p = b.Columns;
if (c == null)
{
c = new DenseDoubleMatrix2D(m, p);
}
if (b.Rows != n)
{
throw new ArgumentOutOfRangeException("b", String.Format(Cern.LocalizedResources.Instance().Exception_Matrix2DInnerDimensionMustAgree, this, b));
}
if (c.Rows != m || c.Columns != p)
{
throw new ArgumentException(String.Format(Cern.LocalizedResources.Instance().Exception_IncompatibleResultMatrix, this, b, c));
}
if (this == c || b == c)
{
throw new ArithmeticException(Cern.LocalizedResources.Instance().Exception_MatricesMustNotBeIdentical);
}
for (int j = p; --j >= 0;)
{
for (int i = m; --i >= 0;)
{
double s = 0;
for (int k = n; --k >= 0;)
{
s += this[i, k] * b[k, j];
}
c[i, j] = (alpha * s) + (beta * c[i, j]);
}
}
return(c);
}
/// <summary>
/// Linear algebraic matrix-matrix multiplication; <tt>C = alpha * A x B + beta*C</tt>.
/// </summary>
/// <param name="b">
/// The second source matrix.
/// </param>
/// <param name="c">
/// The matrix where results are to be storedd Set this parameter to <tt>null</tt> to indicate that a new result matrix shall be constructed.
/// </param>
/// <param name="alpha">
/// The alpha.
/// </param>
/// <param name="beta">
/// The beta.
/// </param>
/// <param name="transposeA">
/// Whether A must be transposed.
/// </param>
/// <param name="transposeB">
/// Whether B must be transposed.
/// </param>
/// <returns>
/// C (for convenience only).
/// </returns>
/// <exception cref="ArgumentOutOfRangeException">
/// If <tt>B.rows() != A.columns()</tt>.
/// </exception>
/// <exception cref="ArgumentException">
/// If <tt>C.rows() != A.rows() || C.columns() != B.columns()</tt>.
/// </exception>
/// <exception cref="ArithmeticException">
/// If <tt>A == C || B == C</tt>.
/// </exception>
public virtual DoubleMatrix2D ZMult(DoubleMatrix2D b, DoubleMatrix2D c, double alpha, double beta, bool transposeA, bool transposeB)
{
if (transposeA)
{
return(ViewDice().ZMult(b, c, alpha, beta, false, transposeB));
}
if (transposeB)
{
return(ZMult(b.ViewDice(), c, alpha, beta, false, false));
}
int m = Rows;
int n = Columns;
int p = b.Columns;
if (c == null)
{
c = new DenseDoubleMatrix2D(m, p);
}
if (b.Rows != n)
{
throw new ArgumentOutOfRangeException("b", "Matrix2D inner dimensions must agree:" + this + ", " + b);
}
if (c.Rows != m || c.Columns != p)
{
throw new ArgumentException("Incompatible result matrix: " + this + ", " + b + ", " + c);
}
if (this == c || b == c)
{
throw new ArithmeticException("Matrices must not be identical");
}
for (int j = p; --j >= 0;)
{
for (int i = m; --i >= 0;)
{
double s = 0;
for (int k = n; --k >= 0;)
{
s += this[i, k] * b[k, j];
}
c[i, j] = (alpha * s) + (beta * c[i, j]);
}
}
return(c);
}
/// <summary>
/// Modifies the given matrix to be a randomly sampled matrix.
/// Randomly picks exactly <i>System.Math.Round(rows*columns*nonZeroFraction)</i> cells and initializes them to <i>value</i>, all the rest will be initialized to zero.
/// Note that this is not the same as setting each cell with probability <i>nonZeroFraction</i> to <i>value</i>.
/// Note: The random seed is a constant.
/// </summary>
/// <param name="factory"></param>
/// <param name="matrix"></param>
/// <param name="value"></param>
/// <param name="nonZeroFraction"></param>
/// <returns></returns>
/// <exception cref="ArgumentException">if nonZeroFraction < 0 || nonZeroFraction > 1.</exception>
/// <see cref="Cern.Jet.Random.Sampling.RandomSamplingAssistant"/>
public static DoubleMatrix2D Sample(this DoubleFactory2D factory, DoubleMatrix2D matrix, double value, double nonZeroFraction)
{
int rows = matrix.Rows;
int columns = matrix.Columns;
double epsilon = 1e-09;
if (nonZeroFraction < 0 - epsilon || nonZeroFraction > 1 + epsilon)
{
throw new ArgumentException();
}
if (nonZeroFraction < 0)
{
nonZeroFraction = 0;
}
if (nonZeroFraction > 1)
{
nonZeroFraction = 1;
}
matrix.Assign(0);
int size = rows * columns;
int n = (int)System.Math.Round(size * nonZeroFraction);
if (n == 0)
{
return(matrix);
}
var sampler = new Cern.Jet.Random.Sampling.RandomSamplingAssistant(n, size, new Cern.Jet.Random.Engine.MersenneTwister());
for (int i = 0; i < size; i++)
{
if (sampler.SampleNextElement())
{
int row = (int)(i / columns);
int column = (int)(i % columns);
matrix[row, column] = value;
}
}
return(matrix);
}
/// <summary>
/// 8 neighbor stencil transformationd For efficient finite difference operations.
/// Applies a function to a moving <tt>3 x 3</tt> window.
/// Does nothing if <tt>rows() < 3 || columns() < 3</tt>.
/// </summary>
/// <param name="b">
/// The matrix to hold the results.
/// </param>
/// <param name="function">
/// The function to be applied to the 9 cells.
/// </param>
/// <exception cref="ArgumentNullException">
/// If <tt>function==null</tt>.
/// </exception>
/// <exception cref="ArgumentOutOfRangeException">
/// If <tt>rows() != B.rows() || columns() != B.columns()</tt>.
/// </exception>
public virtual void ZAssign8Neighbors(DoubleMatrix2D b, Double9Function function)
{
if (function == null)
{
throw new ArgumentNullException("function", Cern.LocalizedResources.Instance().Exception_FuncionMustNotBeNull);
}
CheckShape(b);
if (Rows < 3 || Columns < 3)
{
return; // nothing to do
}
int r = Rows - 1;
int c = Columns - 1;
for (int i = 1; i < r; i++)
{
double a00 = this[i - 1, 0];
double a01 = this[i - 1, 1];
double a10 = this[i, 0];
double a11 = this[i, 1];
double a20 = this[i + 1, 0];
double a21 = this[i + 1, 1];
for (int j = 1; j < c; j++)
{
// in each step six cells can be remembered in registers - they don't need to be reread from slow memory
// in each step 3 instead of 9 cells need to be read from memory.
double a02 = this[i - 1, j + 1];
double a12 = this[i, j + 1];
double a22 = this[i + 1, j + 1];
b[i, j] = function(a00, a01, a02, a10, a11, a12, a20, a21, a22);
a00 = a01;
a10 = a11;
a20 = a21;
a01 = a02;
a11 = a12;
a21 = a22;
}
}
}
/// <summary>
/// Construct a matrix from a one-dimensional column-major packed array, ala Fortran.
/// </summary>
/// <param name="values">
/// One-dimensional array of doubles, packed by columns (ala Fortran).
/// </param>
/// <param name="rows">
/// The number of rows.
/// </param>
/// <returns>
/// A matrix.
/// </returns>
/// <exception cref="ArgumentException">
/// <tt>values.length</tt> must be a multiple of <tt>rows</tt>.
/// </exception>
public DoubleMatrix2D Make(double[] values, int rows)
{
int columns = rows != 0 ? values.Length / rows : 0;
if (rows * columns != values.Length)
{
throw new ArgumentException(Cern.LocalizedResources.Instance().Exception_ArrayLengthMustBeAMultipleOfM);
}
DoubleMatrix2D matrix = Make(rows, columns);
for (int row = 0; row < rows; row++)
{
for (int column = 0; column < columns; column++)
{
matrix[row, column] = values[row + (column * rows)];
}
}
return(matrix);
}
/// <summary>
/// Construct a matrix from a one-dimensional column-major packed array, ala Fortran.
/// </summary>
/// <param name="values">
/// One-dimensional array of doubles, packed by columns (ala Fortran).
/// </param>
/// <param name="rows">
/// The number of rows.
/// </param>
/// <returns>
/// A matrix.
/// </returns>
/// <exception cref="ArgumentException">
/// <tt>values.length</tt> must be a multiple of <tt>rows</tt>.
/// </exception>
public DoubleMatrix2D Make(double[] values, int rows)
{
int columns = rows != 0 ? values.Length / rows : 0;
if (rows * columns != values.Length)
{
throw new ArgumentException("Array length must be a multiple of m.");
}
DoubleMatrix2D matrix = Make(rows, columns);
for (int row = 0; row < rows; row++)
{
for (int column = 0; column < columns; column++)
{
matrix[row, column] = values[row + (column * rows)];
}
}
return(matrix);
}
/// <summary>
/// Applies a function to each corresponding cell of two matrices and aggregates the results.
/// </summary>
/// <param name="other">
/// The other.
/// </param>
/// <param name="aggr">
/// An aggregation function taking as first argument the current aggregation and as second argument the transformed current cell values.
/// </param>
/// <param name="f">
/// A function transforming the current cell values.
/// </param>
/// <returns>
/// The aggregated measure.
/// </returns>
/// <exception cref="ArgumentException">
/// If <tt>columns() != other.columns() || rows() != other.rows()</tt>
/// </exception>
public double Aggregate(DoubleMatrix2D other, DoubleDoubleFunction aggr, DoubleDoubleFunction f)
{
CheckShape(other);
if (Size == 0)
{
return(double.NaN);
}
double a = f(this[Rows - 1, Columns - 1], other[Rows - 1, Columns - 1]);
int d = 1; // last cell already done
for (int row = Rows; --row >= 0;)
{
for (int column = Columns - d; --column >= 0;)
{
a = aggr(a, f(this[row, column], other[row, column]));
}
d = 0;
}
return(a);
}
/// <summary>
/// Replaces all cell values of the receiver with the values of another matrix.
/// Both matrices must have the same number of rows and columns.
/// If both matrices share the same cells (as is the case if they are views derived from the same matrix) and intersect in an ambiguous way, then replaces <i>as if</i> using an intermediate auxiliary deep copy of <tt>other</tt>.
/// </summary>
/// <param name="other">
/// The source matrix to copy from (may be identical to the receiver).
/// </param>
/// <returns>
/// <tt>this</tt> (for convenience only).
/// </returns>
/// <exception cref="ArgumentException">
/// If <tt>columns() != other.columns() || rows() != other.rows()</tt>
/// </exception>
public virtual DoubleMatrix2D Assign(DoubleMatrix2D other)
{
if (other == this)
{
return(this);
}
CheckShape(other);
if (HaveSharedCells(other))
{
other = other.Copy();
}
for (int row = Rows; --row >= 0;)
{
for (int column = Columns; --column >= 0;)
{
this[row, column] = other[row, column];
}
}
return(this);
}
/// <summary>
/// C = A||B; Constructs a new matrix which is the row-wise concatenation of two other matrices.
/// </summary>
/// <param name="a">
/// The matrix A.
/// </param>
/// <param name="b">
/// The matrix B.
/// </param>
/// <returns>
/// A new matrix which is the row-wise concatenation of A and B.
/// </returns>
public DoubleMatrix2D AppendRows(DoubleMatrix2D a, DoubleMatrix2D b)
{
// force both to have maximal shared number of columns.
if (b.Columns > a.Columns)
{
b = b.ViewPart(0, 0, b.Rows, a.Columns);
}
else if (b.Columns < a.Columns)
{
a = a.ViewPart(0, 0, a.Rows, b.Columns);
}
// concatenate
int ar = a.Rows;
int br = b.Rows;
int c = a.Columns;
DoubleMatrix2D matrix = Make(ar + br, c);
matrix.ViewPart(0, 0, ar, c).Assign(a);
matrix.ViewPart(ar, 0, br, c).Assign(b);
return(matrix);
}
/// <summary>
/// C = A||B; Constructs a new matrix which is the column-wise concatenation of two other matrices.
/// </summary>
/// <param name="a">
/// The matrix A.
/// </param>
/// <param name="b">
/// The matrix B.
/// </param>
/// <returns>
/// The column-wise concatenation of A and B.
/// </returns>
public DoubleMatrix2D AppendColumns(DoubleMatrix2D a, DoubleMatrix2D b)
{
// force both to have maximal shared number of rows.
if (b.Rows > a.Rows)
{
b = b.ViewPart(0, 0, a.Rows, b.Columns);
}
else if (b.Rows < a.Rows)
{
a = a.ViewPart(0, 0, b.Rows, a.Columns);
}
// concatenate
int ac = a.Columns;
int bc = b.Columns;
int r = a.Rows;
DoubleMatrix2D matrix = Make(r, ac + bc);
matrix.ViewPart(0, 0, r, ac).Assign(a);
matrix.ViewPart(0, ac, r, bc).Assign(b);
return(matrix);
}
/// <summary>
/// Returns <tt>true</tt> if both matrices share at least one identical cell.
/// </summary>
/// <param name="other">
/// The other matrix.
/// </param>
/// <returns>
/// <tt>true</tt> if both matrices share at least one identical cell.
/// </returns>
protected virtual bool HaveSharedCellsRaw(DoubleMatrix2D other)
{
return(false);
}
/// <summary>
/// Constructs a block matrix made from the given parts.
/// <para>
/// All matrices of a given column within <tt>parts</tt> must have the same number of columns.
/// All matrices of a given row within <tt>parts</tt> must have the same number of rows.
/// Otherwise an <tt>IllegalArgumentException</tt> is thrown.
/// <tt>null</tt>s within <tt>parts[row,col]</tt> are an exception to this rule: they are ignored.
/// Cells are copied.
/// </para>
/// </summary>
/// <param name="parts">
/// The parts.
/// </param>
/// <returns>
/// A block matrix.
/// </returns>
/// <exception cref="ArgumentOutOfRangeException">
/// If the parts are not subject to the conditions outlined above.
/// </exception>
public DoubleMatrix2D Compose(DoubleMatrix2D[][] parts)
{
checkRectangularShape(parts);
int rows = parts.Length;
int columns = 0;
if (parts.Length > 0)
{
columns = parts[0].Length;
}
DoubleMatrix2D empty = Make(0, 0);
if (rows == 0 || columns == 0)
{
return(empty);
}
// determine maximum column width of each column
var maxWidths = new int[columns];
for (int column = columns; --column >= 0;)
{
int maxWidth = 0;
for (int row = rows; --row >= 0;)
{
DoubleMatrix2D part = parts[row][column];
if (part != null)
{
int width = part.Columns;
if (maxWidth > 0 && width > 0 && width != maxWidth)
{
throw new ArgumentOutOfRangeException("parts", "Different number of columns.");
}
maxWidth = Math.Max(maxWidth, width);
}
}
maxWidths[column] = maxWidth;
}
// determine row height of each row
var maxHeights = new int[rows];
for (int row = rows; --row >= 0;)
{
int maxHeight = 0;
for (int column = columns; --column >= 0;)
{
DoubleMatrix2D part = parts[row][column];
if (part != null)
{
int height = part.Rows;
if (maxHeight > 0 && height > 0 && height != maxHeight)
{
throw new ArgumentOutOfRangeException("parts", "Different number of rows.");
}
maxHeight = Math.Max(maxHeight, height);
}
}
maxHeights[row] = maxHeight;
}
// shape of result
int resultRows = 0;
for (int row = rows; --row >= 0;)
{
resultRows += maxHeights[row];
}
int resultCols = 0;
for (int column = columns; --column >= 0;)
{
resultCols += maxWidths[column];
}
DoubleMatrix2D matrix = Make(resultRows, resultCols);
// copy
int r = 0;
for (int row = 0; row < rows; row++)
{
int c = 0;
for (int column = 0; column < columns; column++)
{
DoubleMatrix2D part = parts[row][column];
if (part != null)
{
matrix.ViewPart(r, c, part.Rows, part.Columns).Assign(part);
}
c += maxWidths[column];
}
r += maxHeights[row];
}
return(matrix);
}
/// <summary>
/// Splits a block matrix into its constituent blocks; Copies blocks of a matrix into the given parts.
/// <para>
/// All matrices of a given column within <tt>parts</tt> must have the same number of columns.
/// All matrices of a given row within <tt>parts</tt> must have the same number of rows.
/// Otherwise an <tt>IllegalArgumentException</tt> is thrown.
/// <tt>null</tt>s within <tt>parts[row,col]</tt> are an exception to this rule: they are ignored.
/// Cells are copied.
/// </para>
/// </summary>
/// <param name="parts">
/// The parts.
/// </param>
/// <param name="matrix">
/// The matrix.
/// </param>
/// <exception cref="ArgumentException">
/// subject to the conditions outlined above.
/// </exception>
public void Decompose(DoubleMatrix2D[][] parts, DoubleMatrix2D matrix)
{
checkRectangularShape(parts);
int rows = parts.Length;
int columns = 0;
if (parts.Length > 0)
{
columns = parts[0].Length;
}
if (rows == 0 || columns == 0)
{
return;
}
// determine maximum column width of each column
var maxWidths = new int[columns];
for (int column = columns; --column >= 0;)
{
int maxWidth = 0;
for (int row = rows; --row >= 0;)
{
DoubleMatrix2D part = parts[row][column];
if (part != null)
{
int width = part.Columns;
if (maxWidth > 0 && width > 0 && width != maxWidth)
{
throw new ArgumentException("Different number of columns.");
}
maxWidth = Math.Max(maxWidth, width);
}
}
maxWidths[column] = maxWidth;
}
// determine row height of each row
var maxHeights = new int[rows];
for (int row = rows; --row >= 0;)
{
int maxHeight = 0;
for (int column = columns; --column >= 0;)
{
DoubleMatrix2D part = parts[row][column];
if (part != null)
{
int height = part.Rows;
if (maxHeight > 0 && height > 0 && height != maxHeight)
{
throw new ArgumentException("Different number of rows.");
}
maxHeight = Math.Max(maxHeight, height);
}
}
maxHeights[row] = maxHeight;
}
// shape of result parts
int resultRows = 0;
for (int row = rows; --row >= 0;)
{
resultRows += maxHeights[row];
}
int resultCols = 0;
for (int column = columns; --column >= 0;)
{
resultCols += maxWidths[column];
}
if (matrix.Rows < resultRows || matrix.Columns < resultCols)
{
throw new ArgumentException("Parts larger than matrix.");
}
// copy
int r = 0;
for (int row = 0; row < rows; row++)
{
int c = 0;
for (int column = 0; column < columns; column++)
{
DoubleMatrix2D part = parts[row][column];
if (part != null)
{
part.Assign(matrix.ViewPart(r, c, part.Rows, part.Columns));
}
c += maxWidths[column];
}
r += maxHeights[row];
}
}
/// <summary>
/// Linear algebraic matrix-matrix multiplication; <tt>C = A x B</tt>.
/// </summary>
/// <param name="b">
/// The matrix B.
/// </param>
/// <param name="c">
/// The matrix C.
/// </param>
/// <returns>
/// The matrix C (for convenience only).
/// </returns>
public DoubleMatrix2D ZMult(DoubleMatrix2D b, DoubleMatrix2D c)
{
return(ZMult(b, c, 1, (c == null ? 1 : 0), false, false));
}
/// <summary>
/// Constructs a randomly sampled matrix with the given shape.
/// Randomly picks exactly<tt>Math.round(rows* columns* nonZeroFraction)</tt> cells and initializes them to<tt> value</tt>, all the rest will be initialized to zero.
/// Note that this is not the same as setting each cell with probability<tt> nonZeroFraction</tt> to<tt> value</tt>.
/// Note: The random seed is a constant.
/// </summary>
/// <param name="factory"></param>
/// <param name="rows"></param>
/// <param name="columns"></param>
/// <param name="value"></param>
/// <param name="nonZeroFraction"></param>
/// <returns></returns>
/// <exception cref="ArgumentException">if nonZeroFraction < 0 || nonZeroFraction > 1.</exception>
/// <see cref="Cern.Jet.Random.Sampling.RandomSamplingAssistant"/>
public static DoubleMatrix2D Sample(this DoubleFactory2D factory, int rows, int columns, double value, double nonZeroFraction)
{
DoubleMatrix2D matrix = factory.Make(rows, columns);
return(Sample(factory, matrix, value, nonZeroFraction));
}