Class: Matrix

Inherits:
Object
  • Object
show all
Includes:
Enumerable, MatrixErr, Properties
Defined in:
lib/matrix_gem.rb

Instance Method Summary collapse

Methods included from Properties

#col, #col_length, #row, #row_change, #row_length, #to_a

Constructor Details

#initialize(rows, cols, *nums) ⇒ Matrix

———Initialize the matrix——

1. Matrix with values
   Matrix.new(rows, cols, numbers) // numbers = rows*cols
2. Matrix only with dimention(rows and cols) make Identity matrix
   Matrix.new(rows, cols)



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# File 'lib/matrix_gem.rb', line 15

def initialize(rows, cols, *nums)
  if rows < 1 || cols < 1
    raise MatrixArgumentError, "Rows and Columns should be positive numbers!"
  elsif nums.length == 0
    @matrix = identity cols
  elsif rows * cols == nums.length
    @matrix = matrix_with_values nums, cols
  else
    raise MatrixArgumentError,
    "Wrong number of arguments (#{2 + nums.length} for #{2 + rows * cols})"
  end
  @matrix
end

Instance Method Details

#*(m) ⇒ Object

Matrix multiplication.



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# File 'lib/matrix_gem.rb', line 99

def *(m)
  case(m)
  when Numeric
    new_matrix_values = []
    self.each { |x| new_matrix_values << x * m }
    Matrix.new self.m, self.n, *(new_matrix_values)
  when Matrix
    multiply_validation self, m
    rows = Array.new(self.m) { |i|
      Array.new(m.n) { |j|
        (0 ... m.n ).inject(0)  do |vij, k|
          vij + self[i, k] * m[k, j]
        end
      }
    }
  end
end

#+(matrix) ⇒ Object

Return the sum of two matrices in new matrix



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# File 'lib/matrix_gem.rb', line 30

def +(matrix)
  sum_validation(matrix, self)
  values = self.zip(matrix).map{|i| i.inject(:+)}

  Matrix.new self.m, self.n, *(values)
end

#-(matrix) ⇒ Object

Return the difference of two matrices in new matrix



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# File 'lib/matrix_gem.rb', line 38

def -(matrix)
  sum_validation(matrix, self)
  values = self.zip(matrix).map{|i| i.inject(:-)}

  Matrix.new self.m, self.n, *(values)
end

#==(matrix) ⇒ Object

Returns true if and only if the two matrices contain equal elements.



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# File 'lib/matrix_gem.rb', line 94

def ==(matrix)
  matrix.to_a == self.to_a
end

#[](i, j = nil) ⇒ Object

Returns element (i,j) of the matrix. That is: row i, column j. If only i is given return row. That is: row with index i.



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# File 'lib/matrix_gem.rb', line 47

def [](i, j = nil)
  if j == nil
    @matrix[i]
  else
    @matrix[i][j]
  end
end

#[]=(i, j = nil, val) ⇒ Object Also known as: set_element

Set element (i,j) of the matrix. That is: row i, column j. Set row i of the matrix if j is not given. That is: column j. Also aliased as set_element



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# File 'lib/matrix_gem.rb', line 58

def []=(i, j = nil, val)
  if j == nil
    raise ErrDimensionMismatch if val.length != self.m
    @matrix[i] = val
  else
    @matrix[i][j] = val
  end
end

#det ⇒ Object Also known as: determinant

Returns the determinant of the matrix. Also alised as determinant()



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# File 'lib/matrix_gem.rb', line 119

def det
  is_square_validation self

  _this = copy(self)
  c = 1
  new_matrix = nil
  size = _this.n

  (0..size - 2).each do |i|
    (i + 1..size -1).each do |j|
      if _this[i][i] == 0
        (i+1..size-1).each do |k|
          if _this[k,i] != 0
            swap_rows(_this, k, i)
            c *= -1
          end
        end
      end
      if _this[i,i] == 0
        p _this
        return 0
      end

      new_matrix = cauchy_method(_this, i, j, -_this[j,i]/_this[i,i].to_f)
    end
  end

  det = 1

  (0..size-1).each do |i|
    det *= new_matrix[i][i]
  end

  det *= c
  det.round
end

#each ⇒ Object

Each method.



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# File 'lib/matrix_gem.rb', line 85

def each
  @matrix.each  do |sub_arr|
    sub_arr.each do |value|
      yield value
    end
  end
end

#inverse ⇒ Object

Returns the inverse of the matrix.

Raises:



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# File 'lib/matrix_gem.rb', line 163

def inverse
  is_square_validation self
  raise ErrZeroDeterminant if self.det == 0

  _this = copy(self)
  c = 1
  e = Matrix.new _this.m, _this.n
  size = _this.m

  (0..size-2).each do |i|
    (i+1..size-1).each do |j|
      if _this[i, i] == 0
        (i..size-2).each do |k|
          if _this[k, i] != 0
            swap_rows(_this, k, i)
            swap_rows(e, k, i)
            c *= -1
          end
        end
      end

      return 0 if _this[i, i] == 0

      cauchy_method(e, i, j, -_this[j, i]/_this[i, i].to_f)
      cauchy_method(_this, i, j, -_this[j, i]/_this[i, i].to_f)
    end
  end

  (0..size-2).each do |i|
    (i+1..size-1).each do |j|

      cauchy_method(e, size-i-1, size-j-1, -_this[size-j-1, size-i-1]/_this[size-i-1, size-i-1])

      cauchy_method(_this, size-i-1, size-j-1, -_this[size-j-1, size-i-1]/_this[size-i-1, size-i-1])
    end
  end

  (0..size-1).each do |i|
    e.row_change i, multiply_row(e, i, 1/_this[i,i])
    _this.row_change i, multiply_row(_this, i, 1/_this[i,i])
  end
  e
end

#inversed ⇒ Object

Chanege matrix to its inversed.



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# File 'lib/matrix_gem.rb', line 208

def inversed
  elements = []
  self.inverse.each{ |x| elements << x}
  @matrix = elements.each_slice(@matrix[0].length).to_a
end

#multiply_row(matrix, index, number) ⇒ Object

Multiplication of matrix row with number.



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# File 'lib/matrix_gem.rb', line 158

def multiply_row(matrix, index, number)
  matrix = matrix.row(index).map{ |n| n*number }
end

#transpose ⇒ Object Also known as: t

Transpose the matrix. Also aliased as t().



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# File 'lib/matrix_gem.rb', line 77

def transpose
  elements = []
  @matrix.to_a.transpose.map{ |x| x.map{ |y| elements << y } }
  @matrix = elements.each_slice(@matrix[0].length).to_a
end

#transposed ⇒ Object

Return a new matrix which is the transposition of the given one.



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# File 'lib/matrix_gem.rb', line 69

def transposed
  elements = []
  @matrix.to_a.transpose.map{ |x| x.map{ |y| elements << y } }
  Matrix.new self.m, self.n, *(elements)
end