Mathematica 9 is now available
Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2008

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

Search the Archive

Re: Deleting Integrate[] transformation rule

  • To: mathgroup at smc.vnet.net
  • Subject: [mg87609] Re: Deleting Integrate[] transformation rule
  • From: UHAP023 at alpha1.rhbnc.ac.uk
  • Date: Mon, 14 Apr 2008 05:44:49 -0400 (EDT)
  • References: <ftq5ab$it$1@smc.vnet.net> <ftscv1$b81$1@smc.vnet.net>

Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com> wrote:
: UHAP023 at alpha1.rhbnc.ac.uk wrote:

: > When integrating Mathematica knows the result of D[EllipticF[phi,m, phi]] =
: ====================================================================!!
: Syntax error: a square bracket is missing.

: > 1/Sqrt[1-m*Sin[phi]^2]] and will produce expressions containing
: > EllipticF[] in its result when it encounters such a pattern.  I want
: > to prevent this -- that is Unprotect Integrate[] and make it forget
: > this rule so that EllipticF[] will not appear in the result.

: No need to do that: just use the correct syntax as in,

: In[1]:= D[EllipticF[phi, m], phi]

: Out[1]=

:            1
: ---------------------
:                     2
: Sqrt[1 - m Sin[phi] ]

My apologies. I typed the above in a rush, hence the syntax errors -- 
including I notice an extraneous ']' in the derivative expression.  
However you did not address the question.  It must be possible to 
Unprotect Integrate[] and modify it to remove the transformation rule that 
it uses to pattern match and convert integrand expressions of the form 
1/Sqrt[1-m*Sin[phi]^2] to resultant integral expressions of the form 
EllipticF[phi,m] -- thus preventing EllipticF[] appearing in any result 
produced by Integrate[].  It is unclear to me from the Mathematica 4.0 docs
I have how to do this.  The Hold* family of functions, HoldComplete in
particular look relevant??  Can anybody confirm/refute and supply a worked
example of this procedure?

Thanks
Tom.

: Regards,
: -- Jean-Marc

Ps. the email address in the header is just a spam trap.

-- 
Tom Crane, Dept. Physics, Royal Holloway, University of London, Egham Hill,
Egham, Surrey, TW20 0EX, England. 
Email:  T.Crane at rhul dot ac dot uk
Fax:    +44 (0) 1784 472794


  • Prev by Date: Re: List concatenation speed
  • Next by Date: Re: List concatenation speed
  • Previous by thread: Re: Deleting Integrate[] transformation rule
  • Next by thread: Re: Re: Deleting Integrate[] transformation rule