#-----------------------------------------------------------------------------
#
#	Author : philippe.billet@noos.fr
#
#	Error function erf(x)
#	erf(-x)=erf(x)
#  
#-----------------------------------------------------------------------------



Eval_erf = ->
	push(cadr(p1))
	Eval()
	yerf()

yerf = ->
	save()
	yyerf()
	restore()

yyerf = ->
	d = 0.0

	p1 = pop()

	if (isdouble(p1))
		d = 1.0 - erfc(p1.d)
		push_double(d)
		return

	if (isnegativeterm(p1))
		push_symbol(ERF)
		push(p1)
		negate()
		list(2)
		negate()
		return
	
	push_symbol(ERF)
	push(p1)
	list(2)
	return