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Курс във Факултета по Математика и Информатика към СУ

Решение на Трета задача от Камелия Пандаклиева

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Към профила на Камелия Пандаклиева

Резултати

  • 6 точки от тестове
  • 0 бонус точки
  • 6 точки общо
  • 13 успешни тест(а)
  • 0 неуспешни тест(а)

Код

class Expr
def self.build(expr_tree)
expr_tree_copy = Array.new expr_tree
if expr_tree_copy.length == 3
Binary.build expr_tree_copy
else
Unary.build expr_tree_copy
end
end
end
class Binary < Expr
attr_reader :left, :right
def self.build(expr_tree)
case expr_tree.shift
when :+ then Addition.new Expr.build(expr_tree.shift), Expr.build(expr_tree.shift)
when :* then Multiplication.new Expr.build(expr_tree.shift), Expr.build(expr_tree.shift)
end
end
def exact?
@left.exact? and @right.exact?
end
def ==(other)
self.class == other.class and left == other.left and right == other.right
end
def !=(other)
not self == other
end
end
class Addition < Binary
def initialize(left, right)
@left, @right = left, right
end
def evaluate(environment = {})
(@left.evaluate environment) + (@right.evaluate environment)
end
def simplify
return Number.new evaluate if exact?
return @left.simplify if @right.exact? and @right.evaluate == 0
return @right.simplify if @left.exact? and @left.evaluate == 0
left, right = @left.simplify, @right.simplify
if left == @left and right == @right
Addition.new(left, right)
else
Addition.new(left, right).simplify
end
end
def derive(variable)
Addition.new(@left.derive(variable), @right.derive(variable)).simplify
end
end
class Multiplication < Binary
def initialize(left, right)
@left, @right = left, right
end
def evaluate(environment = {})
(@left.evaluate environment) * (@right.evaluate environment)
end
def simplify
return Number.new evaluate if exact?
if @left.exact?
return Number.new 0 if @left.evaluate == 0
return @right.simplify if @left.evaluate == 1
end
if @right.exact?
return Number.new 0 if @right.evaluate == 0
return @left.simplify if @right.evaluate == 1
end
if @left == @left.simplify and @right == @right.simplify
Multiplication.new(@left.simplify, @right.simplify)
else
Multiplication.new(@left.simplify, @right.simplify).simplify
end
end
def derive(variable)
left = Multiplication.new @left.derive(variable), @right
right = Multiplication.new @left, @right.derive(variable)
Addition.new(left, right).simplify
end
end
class Unary < Expr
attr_reader :arg
def self.build(expr_tree)
case expr_tree.shift
when :number then Number.new expr_tree.shift
when :variable then Variable.new expr_tree.shift
when :- then Negation.new Expr.build expr_tree.shift
when :sin then Sine.new Expr.build expr_tree.shift
when :cos then Cosine.new Expr.build expr_tree.shift
end
end
def exact?
@arg.exact?
end
def ==(other)
self.class == other.class and arg == other.arg
end
def !=(other)
not self == other
end
end
class Negation < Unary
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
-(@arg.evaluate environment)
end
def simplify
return Number.new evaluate if exact?
Negation.new @arg.simplify
end
def derive(variable)
Negation.new(@arg.derive(variable)).simplify
end
end
class Sine < Unary
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
Math.sin @arg.evaluate environment
end
def simplify
return Number.new evaluate if exact?
Sine.new @arg.simplify
end
def derive(variable)
Multiplication.new(@arg.derive(variable), Cosine.new(@arg)).simplify
end
end
class Cosine < Unary
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
Math.cos @arg.evaluate environment
end
def simplify
return Number.new evaluate if exact?
Cosine.new @arg.simplify
end
def derive(variable)
Multiplication.new(@arg.derive(variable), Negation.new(Sine.new(@arg))).simplify
end
end
class Variable < Unary
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
raise "uninitialized variable" if not environment.has_key? @arg
environment.fetch @arg
end
def simplify
self
end
def derive(variable)
return Number.new 1 if variable == @arg
return Number.new 0
end
def exact?
false
end
end
class Number < Unary
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
@arg
end
def simplify
self
end
def derive(variable)
Number.new 0
end
def exact?
true
end
end

Лог от изпълнението

.............

Finished in 0.04955 seconds
13 examples, 0 failures

История (4 версии и 0 коментара)

Камелия обнови решението на 11.11.2012 03:57 (преди около 12 години)

+class Expr
+ def self.build(expr_tree)
+ if expr_tree.length == 3
+ Binary.build expr_tree
+ else
+ Unary.build expr_tree
+ end
+ end
+end
+
+class Binary < Expr
+ def self.build(expr_tree)
+ case expr_tree.shift
+ when :+ then Addition.new Expr.build(expr_tree.shift), Expr.build(expr_tree.shift)
+ when :* then Multiplication.new Expr.build(expr_tree.shift), Expr.build(expr_tree.shift)
+ end
+ end
+end
+
+class Addition < Binary
+ attr_reader :left, :right
+
+ def initialize(left, right)
+ @left, @right = left, right
+ end
+
+ def evaluate(environment = {})
+ (@left.evaluate environment) + (@right.evaluate environment)
+ end
+
+ def simplify
+ return Number.new evaluate if exact?
+ return @left.simplify if @right.exact? and @right.evaluate == 0
+ return @right.simplify if @left.exact? and @left.evaluate == 0
+ Addition.new @left.simplify, @right.simplify
+ end
+
+ def derive(variable)
+ Addition.new(@left.derive(variable), @right.derive(variable)).simplify
+ end
+
+ def exact?
+ @left.exact? and @right.exact?
+ end
+
+ def ==(other)
+ self.class == other.class and left == other.left and right == other.right
+ end
+end
+
+class Multiplication < Binary
+ attr_reader :left, :right
+
+ def initialize(left, right)
+ @left, @right = left, right
+ end
+
+ def evaluate(environment = {})
+ (@left.evaluate environment) * (@right.evaluate environment)
+ end
+
+ def simplify
+ return Number.new evaluate if exact?
+ if @left.exact?
+ return Number.new 0 if @left.evaluate == 0
+ return @right.simplify if @left.evaluate == 1
+ end
+ if @right.exact?
+ return Number.new 0 if @right.evaluate == 0
+ return @left.simplify if @right.evaluate == 1
+ end
+ Multiplication.new @left.simplify, @right.simplify
+ end
+
+ def derive(variable)
+ left = Multiplication.new @left.derive(variable), @right
+ right = Multiplication.new @right, @left.derive(variable)
+ Addition.new(left, right).simplify
+ end
+
+ def exact?
+ @left.exact? and @right.exact?
+ end
+
+ def ==(other)
+ self.class == other.class and left == other.left and right == other.right
+ end
+end
+
+class Unary < Expr
+ def self.build(expr_tree)
+ case expr_tree.shift
+ when :number then Number.new expr_tree.shift
+ when :variable then Variable.new expr_tree.shift
+ when :- then Negation.new Expr.build expr_tree.shift
+ when :sin then Sine.new Expr.build expr_tree.shift
+ when :cos then Cosine.new Expr.build expr_tree.shift
+ end
+ end
+end
+
+class Negation < Unary
+ attr_reader :arg
+
+ def initialize(arg)
+ @arg = arg
+ end
+
+ def evaluate(environment = {})
+ -(@arg.evaluate environment)
+ end
+
+ def simplify
+ return Number.new evaluate if exact?
+ Negation.new @arg.simplify
+ end
+
+ def derive(variable)
+ Negation.new(@arg.derive(variable)).simplify
+ end
+
+ def exact?
+ @arg.exact?
+ end
+
+ def ==(other)
+ self.class == other.class and arg == other.arg
+ end
+end
+
+class Sine < Unary
+ attr_reader :arg
+
+ def initialize(arg)
+ @arg = arg
+ end
+
+ def evaluate(environment = {})
+ Math.sin @arg.evaluate environment
+ end
+
+ def simplify
+ return Number.new evaluate if exact?
+ Sine.new @arg.simplify
+ end
+
+ def derive(variable)
+ Multiplication.new(@arg.derive(variable), Cosine.new(@arg)).simplify
+ end
+
+ def exact?
+ @arg.exact?
+ end
+
+ def ==(other)
+ self.class == other.class and arg == other.arg
+ end
+end
+
+class Cosine < Unary
+ attr_reader :arg
+
+ def initialize(arg)
+ @arg = arg
+ end
+
+ def evaluate(environment = {})
+ Math.cos @arg.evaluate environment
+ end
+
+ def simplify
+ return Number.new evaluate if exact?
+ Cosine.new @arg.simplify
+ end
+
+ def derive(variable)
+ Multiplication.new(@arg.derive(variable), Negation.new(Sine.new(@arg))).simplify
+ end
+
+ def exact?
+ @arg.exact?
+ end
+
+ def ==(other)
+ self.class == other.class and arg == other.arg
+ end
+end
+
+class Variable < Unary
+ attr_reader :arg
+
+ def initialize(arg)
+ @arg = arg
+ end
+
+ def evaluate(environment = {})
+ raise "uninitialized variable" if not environment.has_key? @arg
+ environment.fetch @arg
+ end
+
+ def simplify
+ self
+ end
+
+ def derive(variable)
+ return Number.new 1 if variable == @arg
+ return Number.new 0
+ end
+
+ def exact?
+ false
+ end
+
+ def ==(other)
+ self.class == other.class and arg == other.arg
+ end
+end
+
+class Number < Unary
+ attr_reader :arg
+
+ def initialize(arg)
+ @arg = arg
+ end
+
+ def evaluate(environment = {})
+ @arg
+ end
+
+ def simplify
+ self
+ end
+
+ def derive(variable)
+ Number.new 0
+ end
+
+ def exact?
+ true
+ end
+
+ def ==(other)
+ self.class == other.class and arg == other.arg
+ end
+end

Камелия обнови решението на 11.11.2012 11:20 (преди около 12 години)

class Expr
def self.build(expr_tree)
if expr_tree.length == 3
Binary.build expr_tree
else
Unary.build expr_tree
end
end
end
class Binary < Expr
def self.build(expr_tree)
case expr_tree.shift
when :+ then Addition.new Expr.build(expr_tree.shift), Expr.build(expr_tree.shift)
when :* then Multiplication.new Expr.build(expr_tree.shift), Expr.build(expr_tree.shift)
end
end
end
class Addition < Binary
attr_reader :left, :right
def initialize(left, right)
@left, @right = left, right
end
def evaluate(environment = {})
(@left.evaluate environment) + (@right.evaluate environment)
end
def simplify
return Number.new evaluate if exact?
return @left.simplify if @right.exact? and @right.evaluate == 0
return @right.simplify if @left.exact? and @left.evaluate == 0
- Addition.new @left.simplify, @right.simplify
+ if @left.simplify == @left and @right.simplify == right
+ Addition.new(@left.simplify, @right.simplify)
+ else
+ Addition.new(@left.simplify, @right.simplify).simplify
+ end
end
def derive(variable)
Addition.new(@left.derive(variable), @right.derive(variable)).simplify
end
def exact?
@left.exact? and @right.exact?
end
def ==(other)
self.class == other.class and left == other.left and right == other.right
end
+
+ def !=(other)
+ not self == other
+ end
end
class Multiplication < Binary
attr_reader :left, :right
def initialize(left, right)
@left, @right = left, right
end
def evaluate(environment = {})
(@left.evaluate environment) * (@right.evaluate environment)
end
def simplify
return Number.new evaluate if exact?
if @left.exact?
return Number.new 0 if @left.evaluate == 0
return @right.simplify if @left.evaluate == 1
end
if @right.exact?
return Number.new 0 if @right.evaluate == 0
return @left.simplify if @right.evaluate == 1
end
- Multiplication.new @left.simplify, @right.simplify
+ if @left.simplify == @left and @right.simplify == right
+ Multiplication.new(@left.simplify, @right.simplify)
+ else
+ Multiplication.new(@left.simplify, @right.simplify).simplify
+ end
end
def derive(variable)
left = Multiplication.new @left.derive(variable), @right
- right = Multiplication.new @right, @left.derive(variable)
+ right = Multiplication.new @left, @right.derive(variable)
Addition.new(left, right).simplify
end
def exact?
@left.exact? and @right.exact?
end
def ==(other)
self.class == other.class and left == other.left and right == other.right
end
+
+ def !=(other)
+ not self == other
+ end
end
class Unary < Expr
def self.build(expr_tree)
case expr_tree.shift
when :number then Number.new expr_tree.shift
when :variable then Variable.new expr_tree.shift
when :- then Negation.new Expr.build expr_tree.shift
when :sin then Sine.new Expr.build expr_tree.shift
when :cos then Cosine.new Expr.build expr_tree.shift
end
end
end
class Negation < Unary
attr_reader :arg
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
-(@arg.evaluate environment)
end
def simplify
return Number.new evaluate if exact?
Negation.new @arg.simplify
end
def derive(variable)
Negation.new(@arg.derive(variable)).simplify
end
def exact?
@arg.exact?
end
def ==(other)
self.class == other.class and arg == other.arg
end
+
+ def !=(other)
+ not self == other
+ end
end
class Sine < Unary
attr_reader :arg
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
Math.sin @arg.evaluate environment
end
def simplify
return Number.new evaluate if exact?
Sine.new @arg.simplify
end
def derive(variable)
Multiplication.new(@arg.derive(variable), Cosine.new(@arg)).simplify
end
def exact?
@arg.exact?
end
def ==(other)
self.class == other.class and arg == other.arg
end
+
+ def !=(other)
+ not self == other
+ end
end
class Cosine < Unary
attr_reader :arg
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
Math.cos @arg.evaluate environment
end
def simplify
return Number.new evaluate if exact?
Cosine.new @arg.simplify
end
def derive(variable)
Multiplication.new(@arg.derive(variable), Negation.new(Sine.new(@arg))).simplify
end
def exact?
@arg.exact?
end
def ==(other)
self.class == other.class and arg == other.arg
end
+
+ def !=(other)
+ not self == other
+ end
end
class Variable < Unary
attr_reader :arg
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
raise "uninitialized variable" if not environment.has_key? @arg
environment.fetch @arg
end
def simplify
self
end
def derive(variable)
return Number.new 1 if variable == @arg
return Number.new 0
end
def exact?
false
end
def ==(other)
self.class == other.class and arg == other.arg
end
+
+ def !=(other)
+ not self == other
+ end
end
class Number < Unary
attr_reader :arg
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
@arg
end
def simplify
self
end
def derive(variable)
Number.new 0
end
def exact?
true
end
def ==(other)
self.class == other.class and arg == other.arg
+ end
+
+ def !=(other)
+ not self == other
end
end

Камелия обнови решението на 11.11.2012 12:10 (преди около 12 години)

class Expr
def self.build(expr_tree)
if expr_tree.length == 3
Binary.build expr_tree
else
Unary.build expr_tree
end
end
end
class Binary < Expr
def self.build(expr_tree)
case expr_tree.shift
when :+ then Addition.new Expr.build(expr_tree.shift), Expr.build(expr_tree.shift)
when :* then Multiplication.new Expr.build(expr_tree.shift), Expr.build(expr_tree.shift)
end
end
end
class Addition < Binary
attr_reader :left, :right
def initialize(left, right)
@left, @right = left, right
end
def evaluate(environment = {})
(@left.evaluate environment) + (@right.evaluate environment)
end
def simplify
return Number.new evaluate if exact?
return @left.simplify if @right.exact? and @right.evaluate == 0
return @right.simplify if @left.exact? and @left.evaluate == 0
- if @left.simplify == @left and @right.simplify == right
- Addition.new(@left.simplify, @right.simplify)
+ left, right = @left.simplify, @right.simplify
+ if left == @left and right == @right
+ Addition.new(left, right)
else
- Addition.new(@left.simplify, @right.simplify).simplify
+ Addition.new(left, right).simplify
end
end
def derive(variable)
Addition.new(@left.derive(variable), @right.derive(variable)).simplify
end
def exact?
@left.exact? and @right.exact?
end
def ==(other)
self.class == other.class and left == other.left and right == other.right
end
def !=(other)
not self == other
end
end
class Multiplication < Binary
attr_reader :left, :right
def initialize(left, right)
@left, @right = left, right
end
def evaluate(environment = {})
(@left.evaluate environment) * (@right.evaluate environment)
end
def simplify
return Number.new evaluate if exact?
if @left.exact?
return Number.new 0 if @left.evaluate == 0
return @right.simplify if @left.evaluate == 1
end
if @right.exact?
return Number.new 0 if @right.evaluate == 0
return @left.simplify if @right.evaluate == 1
end
- if @left.simplify == @left and @right.simplify == right
+ if @left == @left.simplify and @right == @right.simplify
Multiplication.new(@left.simplify, @right.simplify)
else
Multiplication.new(@left.simplify, @right.simplify).simplify
end
end
def derive(variable)
left = Multiplication.new @left.derive(variable), @right
right = Multiplication.new @left, @right.derive(variable)
Addition.new(left, right).simplify
end
def exact?
@left.exact? and @right.exact?
end
def ==(other)
self.class == other.class and left == other.left and right == other.right
end
def !=(other)
not self == other
end
end
class Unary < Expr
def self.build(expr_tree)
case expr_tree.shift
when :number then Number.new expr_tree.shift
when :variable then Variable.new expr_tree.shift
when :- then Negation.new Expr.build expr_tree.shift
when :sin then Sine.new Expr.build expr_tree.shift
when :cos then Cosine.new Expr.build expr_tree.shift
end
end
end
class Negation < Unary
attr_reader :arg
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
-(@arg.evaluate environment)
end
def simplify
return Number.new evaluate if exact?
Negation.new @arg.simplify
end
def derive(variable)
Negation.new(@arg.derive(variable)).simplify
end
def exact?
@arg.exact?
end
def ==(other)
self.class == other.class and arg == other.arg
end
def !=(other)
not self == other
end
end
class Sine < Unary
attr_reader :arg
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
Math.sin @arg.evaluate environment
end
def simplify
return Number.new evaluate if exact?
Sine.new @arg.simplify
end
def derive(variable)
Multiplication.new(@arg.derive(variable), Cosine.new(@arg)).simplify
end
def exact?
@arg.exact?
end
def ==(other)
self.class == other.class and arg == other.arg
end
def !=(other)
not self == other
end
end
class Cosine < Unary
attr_reader :arg
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
Math.cos @arg.evaluate environment
end
def simplify
return Number.new evaluate if exact?
Cosine.new @arg.simplify
end
def derive(variable)
Multiplication.new(@arg.derive(variable), Negation.new(Sine.new(@arg))).simplify
end
def exact?
@arg.exact?
end
def ==(other)
self.class == other.class and arg == other.arg
end
def !=(other)
not self == other
end
end
class Variable < Unary
attr_reader :arg
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
raise "uninitialized variable" if not environment.has_key? @arg
environment.fetch @arg
end
def simplify
self
end
def derive(variable)
return Number.new 1 if variable == @arg
return Number.new 0
end
def exact?
false
end
def ==(other)
self.class == other.class and arg == other.arg
end
def !=(other)
not self == other
end
end
class Number < Unary
attr_reader :arg
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
@arg
end
def simplify
self
end
def derive(variable)
Number.new 0
end
def exact?
true
end
def ==(other)
self.class == other.class and arg == other.arg
end
def !=(other)
not self == other
end
end

Камелия обнови решението на 13.11.2012 10:12 (преди около 12 години)

class Expr
def self.build(expr_tree)
- if expr_tree.length == 3
- Binary.build expr_tree
+ expr_tree_copy = Array.new expr_tree
+ if expr_tree_copy.length == 3
+ Binary.build expr_tree_copy
else
- Unary.build expr_tree
+ Unary.build expr_tree_copy
end
end
end
class Binary < Expr
+ attr_reader :left, :right
+
def self.build(expr_tree)
case expr_tree.shift
when :+ then Addition.new Expr.build(expr_tree.shift), Expr.build(expr_tree.shift)
when :* then Multiplication.new Expr.build(expr_tree.shift), Expr.build(expr_tree.shift)
end
end
+
+ def exact?
+ @left.exact? and @right.exact?
+ end
+
+ def ==(other)
+ self.class == other.class and left == other.left and right == other.right
+ end
+
+ def !=(other)
+ not self == other
+ end
end
class Addition < Binary
- attr_reader :left, :right
-
def initialize(left, right)
@left, @right = left, right
end
def evaluate(environment = {})
(@left.evaluate environment) + (@right.evaluate environment)
end
def simplify
return Number.new evaluate if exact?
return @left.simplify if @right.exact? and @right.evaluate == 0
return @right.simplify if @left.exact? and @left.evaluate == 0
left, right = @left.simplify, @right.simplify
if left == @left and right == @right
Addition.new(left, right)
else
Addition.new(left, right).simplify
end
end
def derive(variable)
Addition.new(@left.derive(variable), @right.derive(variable)).simplify
end
-
- def exact?
- @left.exact? and @right.exact?
- end
-
- def ==(other)
- self.class == other.class and left == other.left and right == other.right
- end
-
- def !=(other)
- not self == other
- end
end
class Multiplication < Binary
- attr_reader :left, :right
-
def initialize(left, right)
@left, @right = left, right
end
def evaluate(environment = {})
(@left.evaluate environment) * (@right.evaluate environment)
end
def simplify
return Number.new evaluate if exact?
if @left.exact?
return Number.new 0 if @left.evaluate == 0
return @right.simplify if @left.evaluate == 1
end
if @right.exact?
return Number.new 0 if @right.evaluate == 0
return @left.simplify if @right.evaluate == 1
end
if @left == @left.simplify and @right == @right.simplify
Multiplication.new(@left.simplify, @right.simplify)
else
Multiplication.new(@left.simplify, @right.simplify).simplify
end
end
def derive(variable)
left = Multiplication.new @left.derive(variable), @right
right = Multiplication.new @left, @right.derive(variable)
Addition.new(left, right).simplify
end
-
- def exact?
- @left.exact? and @right.exact?
- end
-
- def ==(other)
- self.class == other.class and left == other.left and right == other.right
- end
-
- def !=(other)
- not self == other
- end
end
class Unary < Expr
+ attr_reader :arg
+
def self.build(expr_tree)
case expr_tree.shift
when :number then Number.new expr_tree.shift
when :variable then Variable.new expr_tree.shift
when :- then Negation.new Expr.build expr_tree.shift
when :sin then Sine.new Expr.build expr_tree.shift
when :cos then Cosine.new Expr.build expr_tree.shift
end
end
+
+ def exact?
+ @arg.exact?
+ end
+
+ def ==(other)
+ self.class == other.class and arg == other.arg
+ end
+
+ def !=(other)
+ not self == other
+ end
end
class Negation < Unary
- attr_reader :arg
-
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
-(@arg.evaluate environment)
end
def simplify
return Number.new evaluate if exact?
Negation.new @arg.simplify
end
def derive(variable)
Negation.new(@arg.derive(variable)).simplify
end
-
- def exact?
- @arg.exact?
- end
-
- def ==(other)
- self.class == other.class and arg == other.arg
- end
-
- def !=(other)
- not self == other
- end
end
class Sine < Unary
- attr_reader :arg
-
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
Math.sin @arg.evaluate environment
end
def simplify
return Number.new evaluate if exact?
Sine.new @arg.simplify
end
def derive(variable)
Multiplication.new(@arg.derive(variable), Cosine.new(@arg)).simplify
end
-
- def exact?
- @arg.exact?
- end
-
- def ==(other)
- self.class == other.class and arg == other.arg
- end
-
- def !=(other)
- not self == other
- end
end
class Cosine < Unary
- attr_reader :arg
-
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
Math.cos @arg.evaluate environment
end
def simplify
return Number.new evaluate if exact?
Cosine.new @arg.simplify
end
def derive(variable)
Multiplication.new(@arg.derive(variable), Negation.new(Sine.new(@arg))).simplify
end
-
- def exact?
- @arg.exact?
- end
-
- def ==(other)
- self.class == other.class and arg == other.arg
- end
-
- def !=(other)
- not self == other
- end
end
class Variable < Unary
- attr_reader :arg
-
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
raise "uninitialized variable" if not environment.has_key? @arg
environment.fetch @arg
end
def simplify
self
end
def derive(variable)
return Number.new 1 if variable == @arg
return Number.new 0
end
def exact?
false
end
-
- def ==(other)
- self.class == other.class and arg == other.arg
- end
-
- def !=(other)
- not self == other
- end
end
class Number < Unary
- attr_reader :arg
-
def initialize(arg)
@arg = arg
end
def evaluate(environment = {})
@arg
end
def simplify
self
end
def derive(variable)
Number.new 0
end
def exact?
true
- end
-
- def ==(other)
- self.class == other.class and arg == other.arg
- end
-
- def !=(other)
- not self == other
end
end