Class: Array

Inherits:
Object
  • Object
show all
Defined in:
lib/arraymethods.rb

Overview

require ‘narray’

Instance Method Summary collapse

Instance Method Details

#*(arg) ⇒ Object

Scalar product



39
40
41
42
43
44
45
46
 
# File 'lib/arraymethods.rb', line 39

def *(arg)
  if self.size != arg.size
    raise "Not equal sizes in scalar product" 
  end
  self.zip(arg).inject(0.0) do |s,(i,j)|
    s + i * j
  end
end

#mean ⇒ Object 



8
9
10
 
# File 'lib/arraymethods.rb', line 8

def mean
  self.sum.to_f / self.size
end

#percentile(percent) ⇒ Object

def median

NArray.to_na(self).median

end



16
17
18
19
20
21
22
23
 
# File 'lib/arraymethods.rb', line 16

def percentile(percent)
  if percent == 0
    [self.min,self.max]
  else
    sorted = self.sort
    [ sorted[(percent/100.0*self.size).round], sorted[((100-percent)/100.0*self.size).round] ]
  end
end

#stddev ⇒ Object 



25
26
27
 
# File 'lib/arraymethods.rb', line 25

def stddev
  Math.sqrt( self.variance )
end

#sum ⇒ Object 



4
5
6
 
# File 'lib/arraymethods.rb', line 4

def sum
  self.inject(0) { |s,i| s + i } 
end

#to_f ⇒ Object 



52
53
54
 
# File 'lib/arraymethods.rb', line 52

def to_f
  self.map{|i| i.to_f}
end

#to_i ⇒ Object 



48
49
50
 
# File 'lib/arraymethods.rb', line 48

def to_i
  self.map{|i| i.to_i}
end

#variance ⇒ Object

Mean square deviation from mean



30
31
32
33
34
35
36
 
# File 'lib/arraymethods.rb', line 30

def variance
  m = self.mean
  sum = self.inject(0) do |s,i|
    s + (i-m)**2
  end
  sum / self.size.to_f
end