Class: Matrix

Inherits:
Object show all
Defined in:
lib/quality_extensions/matrix/linked_vectors.rb,
lib/quality_extensions/matrix/indexable.rb

Overview

Defined Under Namespace

Classes: MatrixDetails

Instance Method Summary collapse

Instance Method Details

#[]=(i, j, new) ⇒ Object

Changes element (i,j) of the matrix. (That is: row i, column j.)



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# File 'lib/quality_extensions/matrix/indexable.rb', line 16

def []=(i, j, new)
  @rows[i][j] = new
end

#column(j) ⇒ Object

Returns column vector number j of the matrix as a Vector (starting at 0 like an array). When a block is given, the elements of that vector are iterated.



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# File 'lib/quality_extensions/matrix/linked_vectors.rb', line 44

def column(j) # :yield: e
  if block_given?
    0.upto(row_size - 1) do
      |i|
      yield @rows[i][j]
    end
  else
    col = (0 .. row_size - 1).collect {
      |i|
      @rows[i][j]
    }
    # With column vectors, it's a bit trickier to link changes so they propagate to the matrix. The matrix doesn't natively store an array of column arrays. The column array constructed here is already a copy. So we pass the matrix by reference and the column number so that we can later use Matrix#[]= to propagate changes to the vector back to the matrix.
    Vector.elements(col, false, MatrixDetails.new(self, j))
  end
end

#row(i) ⇒ Object

Returns row vector number i of the matrix as a Vector (starting at 0 like an array). When a block is given, the elements of that vector are iterated.



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# File 'lib/quality_extensions/matrix/linked_vectors.rb', line 28

def row(i) # :yield: e
  if block_given?
    for e in @rows[i]
      yield e
    end
  else
    # Because an array of rows happens to be the native internal format of a matrix, the only thing changed was passing copy = false instead of copy = true. Then the rows are passed by reference instead of dup'd and any changes made to them will automatically be made in the matrix as well.
    Vector.elements(@rows[i], false)
  end
end