Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2011

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: problem with LessEqual::nord:

  • To: mathgroup at smc.vnet.net
  • Subject: [mg115851] Re: problem with LessEqual::nord:
  • From: Daniel Lichtblau <danl at wolfram.com>
  • Date: Sat, 22 Jan 2011 03:25:04 -0500 (EST)

tarun dutta wrote:
> I am using "NMINIMIZE" to get the result of a function which contains
> complex term.after executing the program it is showing the following
> error--
> LessEqual::nord: Invalid comparison with 155.698+0. I attempted. >>
> 
> can you explain the reason and how will I be free from this kind of
> error?
> thanks in advance.
> regards,
> tarun
> 

It looks like a "phantom" imaginary part that is caused by cancellation 
of imaginary parts in sums of approximate complex numbers. If so, and if 
you know in general that all things you evaluate end up being real (up 
to truncation error) you might get rid of it by wrapping the function 
being evaluated in Re[].

Daniel Lichtblau
Wolfram Research


  • Prev by Date: Re: New Mathematica file format .cdf; what is it?
  • Next by Date: Re: problem with LessEqual::nord:
  • Previous by thread: problem with LessEqual::nord:
  • Next by thread: Re: problem with LessEqual::nord: