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

MathGroup Archive 2009

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

Search the Archive

Re: Mathematica bug??

  • To: mathgroup at smc.vnet.net
  • Subject: [mg100583] Re: Mathematica bug??
  • From: Erik Max Francis <max at alcyone.com>
  • Date: Mon, 8 Jun 2009 03:05:59 -0400 (EDT)
  • References: <h0fvlb$rct$1@smc.vnet.net>

oshaughn wrote:
> {{Sqrt[1 - 2/r], 0, 0, 0}, {0, 1/Sqrt[1 - 2/r], 0, 0}, {0, 0, r,
>    0}, {0, 0, 0, r Sin[\[Theta]]}} // Inverse
> 
> gives
> 
> {{0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 1/r, 0}, {0, 0, 0, Csc[\[Theta]]/
>   r}}
> 
> with no warnings.  This is a *diagonal* matrix that should be
> trivially invertible.
> 
> Does anyone know why Inverse has catastrophically failed here?

For what it's worth, it works properly here:

In[8]:= {{Sqrt[1 - 2/r], 0, 0, 0}, {0, 1/Sqrt[1 - 2/r], 0, 0}, {0, 0,
    r, 0}, {0, 0, 0, r Sin[\[Theta]]}} // Inverse

Out[8]= {{1/Sqrt[1 - 2/r], 0, 0, 0}, {0, Sqrt[1 - 2/r], 0, 0}, {0, 0,
   1/r, 0}, {0, 0, 0, Csc[\[Theta]]/r}}

In[9]:= $Version

Out[9]= "7.0 for Linux x86 (32-bit) (January 30, 2009)"

-- 
Erik Max Francis && max at alcyone.com && http://www.alcyone.com/max/
  San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
   If you are afraid of loneliness, do not marry.
    -- Anton Chekhov


  • Prev by Date: Re: Mathematica bug??
  • Next by Date: Re: Mathematica bug??
  • Previous by thread: Re: Mathematica bug??
  • Next by thread: Re: Mathematica bug??