Method: AppMath::Mat#initialize

Defined in:

lib/linalg.rb

#initialize(*arg) ⇒ Mat

These are the 5 mehods to generate a matrix via ‘new’

m1 = Mat.new(aMat)
m2 = Mat.new(anArrayOfVec)
m3 = Mat.new(aVec)
m4 = Mat.new(aPositiveInteger, aRealOrComplex)
m5 = Mat.new(aPositiveInteger, aPositiveInteger, aRealOrComplex)

Here, m1 is a copy of aMat, m2 is a matrix which has as row vectors, the components of anArrayOfVec. If these vectors have not all he same dimension, failure results; m3 is a square matrix in which only the main diagonal may have non-zero elements, and in which ths diagonal is given as aVec; m4 is a square matrix with the dimension given by the first argument, and with all matrix elements equal to the second argment; m5 is a rectangular matrix with dim1 and dim2 given by the first and the second argument, and with all matrix elements equal to the third argument.

# File 'lib/linalg.rb', line 429

def initialize(*arg)
  case arg.size
  when 0
    @x = Array.new
  when 1 # ok if this is a Matrix or an array of Vectors
    a0 = arg[0]
    if a0.is_a?(Mat)
      @x = Array.new(a0.x)
    elsif a0.is_a?(Array)
      n = a0.size
      if n.zero?
        @x = Array.new
      else
        misfit = 0
        a0.each{|c|
          misfit += 1 unless c.is_a?(Vec)
        }
        fail "input must consist of Vec-objects" unless misfit.zero?
        misfit2 = 0
        d2 = a0[1].dim
        a0.each{|c|
          misfit2 += 1 unless c.dim == d2
        }
        fail "input Vec-objects must agree in dimension" unless 
          misfit.zero?
        @x = a0.clone
      end
    elsif a0.is_a?(Vec) # make a diagonal matrix
      n = a0.dim
      if n.zero?
        @x = Array.new
      else
        c = a0[1].to_0
        vc = Vec.new(n,c)
        @x = Array.new(n,vc)
        for i in 1..n
          s!(i,i,a0[i])
        end
      end
    else
      fail "no reasonable construction available for this argument"
    end
  when 2 # make a square matrix, the diagonal filled with one element
    # (all others zero)
    n = arg[0]
    a = arg[1]
    zero = a.to_0
    vc = Vec.new(n,zero)
    @x = Array.new(n,vc)
    for i in 1..n
      vi = Vec.new(vc)
      vi[i] = a
      @x[i-1] = vi
    end
  when 3 # make rectangular matrix filled with one element
    n1 = arg[0]
    fail "first argument must be integer" unless n1.integer?
    n2 = arg[1]
    fail "second argument must be integer" unless n2.integer?
    a = arg[2]
    vc = Vec.new(n2,a)
    @x = Array.new(n1,vc)
  else
    fail "no construction for more than 3 arguments"
  end
end