Method: Matrix.correspondence_matrix

Defined in:
lib/y_support/stdlib_ext/matrix/misc.rb

.correspondence_matrix(array1, array2) ⇒ Object

Given two arrays, creates correspondence matrix, with no. of cols equal to the 1st array, and no. of rows to the 2nd. This matrix can be used eg. for conversion between column vectors corresponding to the 1st and 2nd array:

Matrix.correspondence_matrix( array1, array2 ) * col_vector_1 #=> col_vector_2



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# File 'lib/y_support/stdlib_ext/matrix/misc.rb', line 39

def self.correspondence_matrix( array1, array2 )
  return Matrix.empty 0, array1.size if array2.empty?
  return Matrix.empty array2.size, 0 if array1.empty?
  self[ *array2.map { |e2| array1.map { |e1| e1 == e2 ? 1 : 0 } } ] # FIXME: Ordinary zero
end