So here (20) is a simpler expression for derivative of arg: (16) -> abs(x)==sqrt(x*conjugate(x)) Compiled code for abs has been cleared. Compiled code for arg has been cleared. 1 old definition(s) deleted for function or rule abs Type: Void (17) -> arg(x)==log(x/abs(x))/%i 1 old definition(s) deleted for function or rule arg Type: Void (18) -> arg %i Compiling function abs with type Complex(Integer) -> Expression( Complex(Integer)) Compiling function arg with type Complex(Integer) -> Expression( Complex(Integer))
(18) - %i log(%i) Type: Expression(Complex(Integer)) (19) -> complexNumeric % (19) 1.5707963267_948966192 Type: Complex(Float) (20) -> D(arg(x),x) Compiling function abs with type Variable(x) -> Expression(Integer) Compiling function arg with type Variable(x) -> Expression(Complex( Integer)) _ - %ix + %i x (20) ------------ _ 2xx Type: Expression(Complex(Integer)) In general I am a little uncertain if, how and when to deal with simplifications of expressions like abs that can be expressed in terms of more fundamental/elementary functions. What do you think? Bill. On 20 November 2014 09:41, Bill Page <bill.p...@newsynthesis.org> wrote: > ... > > I had a thought. I suppose that all non-analytic (nonholomorphic) functions of interest can be written in terms of conjugate and some analytic functions, e.g. > > abs(x)=sqrt(x*conjugate(x)) > > so perhaps all we really need is to know how to differentiate conjugate properly? > > Bill -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.