Method: NMatrix.diagonal

Defined in:

lib/nmatrix/shortcuts.rb

.diagonal(entries, opts = {}) ⇒ Object Also known as: diag, diagonals

call-seq:

diagonals(array) -> NMatrix
diagonals(array, dtype: dtype, stype: stype) -> NMatrix

Creates a matrix filled with specified diagonals.

• Arguments :

  • entries -> Array containing input values for diagonal matrix

  • options -> (optional) Hash with options for NMatrix#initialize

• Returns :

  • NMatrix filled with specified diagonal values.

Examples:

NMatrix.diagonal([1.0,2,3,4]) # => 1.0 0.0 0.0 0.0
                                   0.0 2.0 0.0 0.0
                                   0.0 0.0 3.0 0.0
                                   0.0 0.0 0.0 4.0

NMatrix.diagonal([1,2,3,4], dtype: :int32) # => 1 0 0 0
                                                0 2 0 0
                                                0 0 3 0
                                                0 0 0 4

# File 'lib/nmatrix/shortcuts.rb', line 431

def diagonal(entries, opts={})
  m = NMatrix.zeros(entries.size,
                    {:dtype => guess_dtype(entries[0]), :capacity => entries.size + 1}.merge(opts)
                   )
  entries.each_with_index do |n, i|
    m[i,i] = n
  end
  m
end