Class: EpiMath::Polynomial

Inherits:
Function show all
Defined in:
lib/epimath100/polynomial.class.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from Function

#convert_hash, #get_degree, #get_degree_max

Constructor Details

#initialize(coef = [], verb = 0) ⇒ Polynomial

Initialize the polynominal function Its coeficients are 1, 2, 3, 4 … with ‘1’x⁰ + ‘2’x¹ + ‘3’x² … = y Each coeficients has an associated value (exemple : 2 => 1 correspond to 1x²) exemple : a = [] ; a = 1 ; #correspond to 0 + 0x + 2x³

Parameters:

coef

coef is an array which have several keys 0, 1, 2,… which correspond to the coeficients

verb

default is false

It will display more information if turned on when to_s.
It's a integer, it must be in the list :
- 0 : returns ""
- 1 : "y = equation"
- 2 : "f(x) = equation" (default value)



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# File 'lib/epimath100/polynomial.class.rb', line 26

def initialize coef=[], verb=0
  Error.call "Polynomial::new : Your coef is invalid" if !coef.is_a?Hash and !coef.is_a?Array
  coef = convert_hash(coef) if coef.is_a?Hash
  @coef = coef.select{|v| v.is_a?Numeric}
  @verbose = 2
end

Instance Attribute Details

#coef ⇒ Object

Returns the value of attribute coef.



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# File 'lib/epimath100/polynomial.class.rb', line 9

def coef
  @coef
end

#verb ⇒ Object

Returns the value of attribute verb.



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# File 'lib/epimath100/polynomial.class.rb', line 9

def verb
  @verb
end

Instance Method Details

#calc(x) ⇒ Object

Calculate the value of f(x) from x



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# File 'lib/epimath100/polynomial.class.rb', line 67

def calc x
  y = 0
  [@coef.size].max.times do |coef|
    y += @coef[coef] * x**coef
  end
  return y
end

#derive ⇒ Object

calculate the derivated function of the current polynomial

Returns:

Polynomial (the derivated function)



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# File 'lib/epimath100/polynomial.class.rb', line 36

def derive
  dérivé = Polynomial.new

  if @coef.size > 0
    (1..(@coef.size)).times do |coef|
      dérivé.coef[coef - 1] = dérivé[coef] * coef
    end
  end

  return dérivé
end

#to_s ⇒ Object 



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# File 'lib/epimath100/polynomial.class.rb', line 48

def to_s
  str = ""
  str = "#{@coef[0].to_i}" + str #if @coef[:a]

  if @coef.size > 0
    (1..(@coef.size)).each do |coef|
      #sign = "+"
      #sign = "-" if value < 0
      str = "#{@coef[coef]}x^#{coef} + " + str if @coef[coef].to_f != 0
    end
  end

  str = "f(x) = " + str     if @verb == 2
  str = "y = " + str        if @verb == 1

  return str
end