Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2006
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2006

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

Search the Archive

Re: General--Exponential simplifications by default

  • To: mathgroup at smc.vnet.net
  • Subject: [mg69008] Re: [mg68966] General--Exponential simplifications by default
  • From: Daniel Lichtblau <danl at wolfram.com>
  • Date: Sat, 26 Aug 2006 02:04:56 -0400 (EDT)
  • References: <200608250935.FAA09304@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

guillaume_evin at yahoo.fr wrote:
> Hi !
> 
> I want to avoid simplifications when Mathematica integrates expressions with exponential terms. For example, I have :
> 
> In[8]=      Espcond[y_] = Integrate[x*Densx[x, y], {x, 0, Infinity}, Assumptions -> alpha > 0]
> Out[8]=      E^(-2eta y)(-theta + E^(eta y)(2+theta))/(2alpha)
> 
> I do not want to have a factorization by E^(-2eta y). More precisely I would like to have the following result:
> Out[8]=      (-theta E^(-2eta y)+ E^(-eta y)(2+theta))/(2alpha)
> 
> I guess there is a way to tackle this problem with "ComplexityFunction" and "Simplify", but I tried different things such as "ComplexityFunction -> (Count[{#1}, Exp_, &#8734;] &)" in the "Simplify" function but no change appears.
> 
> Is someone could give me some tricks on how tu use the "ComplexityFunction" ?
> 
> Thank you in advance.
> 
> Guillaume
> 
> Link to the forum page for this post:
> http://www.mathematica-users.org/webMathematica/wiki/wiki.jsp?pageName=Special:Forum_ViewTopic&pid=12974#p12974
> Posted through http://www.mathematica-users.org [[postId=12974]]


Could Collect with respect to powers of the exponential.

In[59]:= ee = E^(-2eta*y)*(-theta + E^(eta*y)(2+theta))/(2*alpha);

In[60]:= InputForm[Collect[ee, Exp[eta*y]]]
Out[60]//InputForm=
-theta/(2*alpha*E^(2*eta*y)) + (2 + theta)/(2*alpha*E^(eta*y))

Daniel Lichtblau
Wolfram Research


  • Prev by Date: Re: Symmetric polynomials
  • Next by Date: Re: How to handle Arrays that has functional parameters:
  • Previous by thread: General--Exponential simplifications by default
  • Next by thread: Re: General--Exponential simplifications by default