Re: Mathematica question
- To: mathgroup at smc.vnet.net
- Subject: [mg85066] Re: Mathematica question
- From: Szabolcs Horvát <szhorvat at gmail.com>
- Date: Sun, 27 Jan 2008 05:40:29 -0500 (EST)
- Organization: University of Bergen
- References: <fnet0b$iaa$1@smc.vnet.net>
None None wrote:
> Dear Sir
>
> I have a problem in mathematica. Consider the following function
> definition. EC1[expr_]:=expr//.{m_ Log[a_]+m_Log[ b_]=A6 m (Log[a]+Log[ b]),m_ Log[a_]-m_Log[ b_]=A6 m (Log[a]-Log[ b])}
> It works fine for "m Log[a]+mLog[b]", but it does not work for
> "m Log[a]-m Log[b]".
>
Hi,
Please convert the expression to InputForm (using ctrl+shift+i) before
posting, otherwise special characters may get damaged during transfer.
Also make sure that you post a plain text message (don't use the rich
text editor of your webmail), and preserve the whitespace: mLog[b] and m
Log[b] are different expressions.
It seems to work fine for the specific examples you posted:
In[1]:= EC1[expr_] :=
expr //. {m_ Log[a_] + m_ Log[b_] -> m (Log[a] + Log[b]),
m_ Log[a_] - m_ Log[b_] -> m (Log[a] - Log[b])}
In[2]:= EC1[m Log[a] + m Log[b]]
Out[2]= m (Log[a] + Log[b])
In[3]:= EC1[m Log[a] - m Log[b]]
Out[3]= m (Log[a] - Log[b])
Szabolcs