Class: Keisan::Functions::Diff

Inherits:
Keisan::Function show all
Defined in:
lib/keisan/functions/diff.rb

Instance Attribute Summary

Attributes inherited from Keisan::Function

#arity, #name

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Diff

Returns a new instance of Diff.



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# File 'lib/keisan/functions/diff.rb', line 4

def initialize
  super("diff", -1)
  @name = "diff"
end

Instance Method Details

#evaluate(ast_function, context = nil) ⇒ Object 



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# File 'lib/keisan/functions/diff.rb', line 21

def evaluate(ast_function, context = nil)
  validate_arguments!(ast_function.children.count)
  context ||= Context.new
  function, variables = function_and_variables(ast_function)
  local = context_from(variables, context)

  result = variables.inject(function.evaluate(local)) do |result, variable|
    result = differentiate(result, variable, local)
    if !is_ast_derivative?(result)
      result = result.evaluate(local)
    end
    result
  end

  case result
  when AST::Function
    result.name == "diff" ? result : result.simplify(context)
  else
    result.simplify(context)
  end
end

#simplify(ast_function, context = nil) ⇒ Object

Raises:



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# File 'lib/keisan/functions/diff.rb', line 43

def simplify(ast_function, context = nil)
  validate_arguments!(ast_function.children.count)
  raise Exceptions::InternalError.new("received non-diff function") unless ast_function.name == "diff"
  function, variables = function_and_variables(ast_function)
  context ||= Context.new
  local = context_from(variables, context)

  result = variables.inject(function.simplify(local)) do |result, variable|
    result = differentiate(result, variable, local)
    if !is_ast_derivative?(result)
      result = result.simplify(local)
    end
    result
  end

  case result
  when AST::Function
    result.name == "diff" ? result : result.simplify(context)
  else
    result.simplify(context)
  end
end

#value(ast_function, context = nil) ⇒ Object 



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# File 'lib/keisan/functions/diff.rb', line 9

def value(ast_function, context = nil)
  validate_arguments!(ast_function.children.count)
  context ||= Context.new
  evaluation = evaluate(ast_function, context)

  if is_ast_derivative?(evaluation)
    raise Exceptions::NonDifferentiableError.new
  else
    evaluation.value(context)
  end
end