Module: CsrMatrix::Arithmetic

Includes:
Contracts::Core
Included in:
TwoDMatrix
Defined in:
lib/csrmatrix/arithmetic.rb

Constant Summary collapse

C = 
Contracts

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(exceptions) ⇒ Object

Brings in exception module for exception testing



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# File 'lib/csrmatrix/arithmetic.rb', line 12

def self.included(exceptions)
  exceptions.send :include, Exceptions
end

Instance Method Details

#count_in_dim ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 282

def count_in_dim()
  is_invariant?
  # helper function, identifies the number of expected values in matrix
  # eg. 2x2 matrix returns 4 values
  return self.rows * self.columns
end

#inverse ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 66

def inverse()
  is_invariant?
  # sets the inverse of this matrix
  # pre   existing matrix (matrix.not_null?)
  # post  inverted matrix
  m = Matrix.rows(self.decompose)
  self.build_from_array(m.inv().to_a())
end

#inverse_multiply(matrix) ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 266

def inverse_multiply(matrix)
  # divides (multiply by the inverse of ) a matrix to existing matrix
  # sets x * y^-1, where x is your matrix and y is the accepted matrix
  is_invariant?
  if !matrix.square? || !self.square?
    raise Exceptions::MatrixDimException.new, "Matrices does not have usable dimensions; cannot divide."
    return false
  end

  tmpmatrix = TwoDMatrix.new
  tmpmatrix = self
  tmpmatrix.inverse()
  return matrix.multiply_csr(tmpmatrix)
end

#is_same_dim(matrix) ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 182

def is_same_dim(matrix)
  # helper function to determine dim count is equal
  is_invariant?
  return self.dimensions() == matrix.dimensions()
end

#matrix_add(matrix) ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 189

def matrix_add(matrix)
  # adds a matrix to existing matrix
  is_invariant?
  if !self.is_same_dim(matrix)
    raise Exceptions::MatrixDimException.new, "Matrix does not have same dimensions; cannot add."
    return false
  end

  res = Array.new(@rows) { Array.new(@columns, 0) }
  row_idx = 0
  cnta = 0 # total logged entries for matrix a 
  cntb = 0
  while row_idx < @rows # eg. 0 1 2
    rowa = @row_ptr[row_idx + 1] # eg. 0 2 4 7
    rowb = matrix.row_ptr[row_idx + 1]
    while cnta < rowa
      # keep adding values to res until they're equal
      res[row_idx][@col_ind[cnta]] += @val[cnta]
      cnta += 1;
    end
    while cntb < rowb
      res[row_idx][@col_ind[cntb]] += matrix.val[cntb]
      cntb += 1;
    end  
    row_idx += 1;
  end
  return res
end

#matrix_division(matrix) ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 290

def matrix_division(matrix)
  # linear division of one matrix to the next
  is_invariant?
  if matrix.val.count() != matrix.count_in_dim()
    raise Exceptions::DivideByZeroException.new, "Calculations return divide by zero error."
    return false
  end 
  if !self.is_same_dim(matrix)
    raise Exceptions::MatrixDimException.new, "Matrix does not have same dimensions; cannot add."
    return false
  end

  res = Array.new(@rows) { Array.new(@columns, 0) }
  row_idx = 0
  cnta = 0 # total logged entries for matrix a 
  cntb = 0
  while row_idx < @rows # eg. 0 1 2
    rowa = @row_ptr[row_idx + 1] # eg. 0 2 4 7
    rowb = matrix.row_ptr[row_idx + 1]
    while cnta < rowa
      # keep adding values to res until they're equal
      res[row_idx][@col_ind[cnta]] += @val[cnta]
      cnta += 1;
    end
    while cntb < rowb
      res[row_idx][@col_ind[cntb]] = res[row_idx][@col_ind[cntb]].to_f / matrix.val[cntb]
      cntb += 1;
    end  
    row_idx += 1;
  end
  return res
end

#matrix_multiply(matrix) ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 143

def matrix_multiply(matrix)
  # multiply dense (non-dense) matrix to csr matrix [eg. [1, 2]] x 2d array
  is_invariant?
  # pre   matrix to multiply, existing matrix (matrix.not_null?)
  # post  array holding resulting matrix
  res = Array.new(max_row(matrix)) { Array.new(@columns, 0) } # first denotes row, second denotes columns
  n = matrix.length
  i = 0
  # res = dense X csr
  csr_row = 0 # Current row in CSR matrix
  while i < n do
    startv = @row_ptr[i] 
    endv = @row_ptr[i + 1]
    j = startv
    while j < endv do
      col = @col_ind[j]
      csr_value = @val[j]
      k = 0
      while k < n do
        dense_value = matrix[k][csr_row]
        res[k][col] += csr_value * dense_value
        k += 1
      end
      j += 1
    end
    csr_row += 1
    i += 1
  end
  return res
end

#matrix_subtract(matrix) ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 219

def matrix_subtract(matrix)
  # subtracts a matrix to existing matrix
  is_invariant?
  if !self.is_same_dim(matrix)
    raise Exceptions::MatrixDimException.new, "Matrix does not have same dimensions; cannot subtract."
    return false
  end

  res = Array.new(@rows) { Array.new(@columns, 0) }
  row_idx = 0
  cnta = 0 # total logged entries for matrix a 
  cntb = 0
  while row_idx < @rows # eg. 0 1 2
    rowa = @row_ptr[row_idx + 1] # eg. 0 2 4 7
    rowb = matrix.row_ptr[row_idx + 1]
    while cnta < rowa
      # keep adding values to res until they're equal
      res[row_idx][@col_ind[cnta]] += @val[cnta]
      cnta += 1;
    end
    while cntb < rowb
      res[row_idx][@col_ind[cntb]] -= matrix.val[cntb]
      cntb += 1;
    end  
    row_idx += 1;
  end
  return res
end

#matrix_vector(vector) ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 124

def matrix_vector(vector) 
  # dev based on http://www.mathcs.emory.edu/~cheung/Courses/561/Syllabus/3-C/sparse.html
  # multiplies the matrix by a vector value (in array form)
  is_invariant?
  result = Array.new(vector.length, 0)
  i = 0
  while i < vector.length do
    k = @row_ptr[i]
    while k < @row_ptr[i+1] do
      result[i] = result[i] + @val[k] * vector[@col_ind[k]]
      k += 1
    end
    i += 1
  end   
  return result
end

#max_row(array) ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 324

def max_row(array)
  # Identifies the 'row' value of an array (eg. the number of entries in a row)
  is_invariant?
  
  values = array
  max_count = 0
  values.each_index do |i|
    max_count += 1
  end
  return max_count
end

#multiply_csr(matrix) ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 175

def multiply_csr(matrix)
  # multiply two csr together - ref: http://www.mcs.anl.gov/papers/P5007-0813_1.pdf
  is_invariant?
  return matrix.matrix_multiply(self.decompose())
end

#multiply_inverse(matrix) ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 249

def multiply_inverse(matrix)
  # divides (multiply by the inverse of ) a matrix to existing matrix
  # sets y * x^-1, where x is your matrix and y is the accepted matrix
  is_invariant?
  if !matrix.square? || !self.square?
    raise Exceptions::MatrixDimException.new, "Matrices does not have usable dimensions; cannot divide."
    return false
  end

  tmpmatrix = TwoDMatrix.new
  tmpmatrix = matrix
  tmpmatrix.inverse()
  return self.multiply_csr(tmpmatrix)
end

#scalar_add(value) ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 27

def scalar_add(value)
  # manipulate the matrix by adding a value at each index
  is_invariant?

  @val.each_index do |i|
    @val[i] = @val[i] + value
  end
end

#scalar_division(value) ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 47

def scalar_division(value)
  is_invariant?
  # manipulate the matrix by dividing the value at each index
  # post  boolean, updated matrix (in floats, if previously was not)
  @val.each_index do |i|
    @val[i] = @val[i] / value.to_f
  end
end

#scalar_exp(value) ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 57

def scalar_exp(value)
  is_invariant?
  # manipulate the matrix by finding the exponential at each index
  @val.each_index do |i|
    @val[i] = @val[i] ** value
  end
end

#scalar_multiply(value) ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 17

def scalar_multiply(value)
  # multiply the matrix by a scalar value
  is_invariant?

  @val.each_index do |i|
    @val[i] = @val[i] * value
  end
end

#scalar_subtract(value) ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 37

def scalar_subtract(value)
  is_invariant? 
  
  # manipulate the matrix by subtracting the value at each index
  @val.each_index do |i|
    @val[i] = @val[i] - value
  end
end

#t ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 116

def t()
  is_invariant?
  # transpose the matrix 
  # post  array of decomposed matrix values
      self.transpose()
end

#transpose ⇒ Object 



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# File 'lib/csrmatrix/arithmetic.rb', line 76

def transpose()
  is_invariant?
  # transpose the matrix 

      new_row_ptr = Array.new(self.columns+1, 0)
      new_col_ind = Array.new(self.col_ind.count(), 0)
      new_val = Array.new(self.val.count(), 0)
      current_row = 0
      current_column = 0
  
      for i in 0..self.columns-1
for j in 0..self.col_ind.count(i)-1
  # get the row
  index = self.col_ind.find_index(i)
  self.col_ind[index] = -1
  for k in 1..self.row_ptr.count()-1
    if self.row_ptr[k-1] <= index && index < self.row_ptr[k]
      current_row = k
      break
    end
  end

  # update values
  new_row_ptr[i+1] += 1
  new_val[current_column] = val[index]
  new_col_ind[current_column] = current_row-1
  current_column += 1
end
      end

      # fill in row_ptr
      for i in 1..self.rows-1
self.row_ptr[i] = new_row_ptr[i] + new_row_ptr[i-1]
      end  

      @col_ind = new_col_ind
      @val = new_val
end