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Re: Matrix manipulation - Thanks!


  • To: mathgroup@smc.vnet.net
  • Subject: [mg12446] Re: Matrix manipulation - Thanks!
  • From: bt585@FreeNet.Carleton.CA (Michael Chang)
  • Date: Tue, 19 May 1998 13:31:17 -0400
  • Organization: The National Capital FreeNet
  • References: <6j5svv$i6g$16@dragonfly.wolfram.com> <6jf0de$3dl@smc.vnet.net>

Hi!

Thanks very much for *all* of your suggestions.  Using the
TraditionalForm option as an output option seems to be a very simple
and effective solution! 

Thanks again!

Mike
 
"Allan Hayes" (hay@haystack.demon.cc.uk) writes:
> Michael Chang <bt585@FreeNet.Carleton.CA>  Subject: [mg12446] [mg12327] Matrix
> manipulation Notes the following
> 
> In[1]:=
>  a={{1,2},{3,4}};
> In[2]:=
> b=a//MatrixForm
> 
> Out[2]//MatrixForm=
> 1   2
> 
> 3   4
> 
> In[3]:=
> Inverse[b]
> 
> Out[3]=
> Inverse[1   2]
> 
>         3   4
> 
> The reason for this is that the FullForm of  b is
> 
> In[4]:=
> FullForm[b]
> 
> Out[4]//FullForm=
> MatrixForm[List[List[1, 2], List[3, 4]]]
> 
> So the FullForm of Inverse[b] is
> In[5]:=
> FullForm[Inverse[b]]
> 
> Out[5]//FullForm=
> Inverse[MatrixForm[List[List[1, 2], List[3, 4]]]]
> 
> 
> -- which shows that Inverse does not get at the matrix inside MatrixForm
> 
> 
> **Two suggestions**
> 
> 1) If we only want to see b formatted two-dimensionally then we can use
> In[6]:=
> (b=a)//MatrixForm
> 
> Out[6]//MatrixForm=
> 1   2
> 
> 3   4
> 
> In[7]:=
> Inverse[b]//MatrixForm
> Out[7]//MatrixForm=
> 
> 
> -2     1
> 
> 3        1
> -      -(-)
> 2        2
> 
> 2) Use TraditionalForm for output - matrices are formatted two
> dimensionally in this.
> 
> 
> -- 
> Allan Hayes
> Mathematica Training and Consulting
> Leicester UK
> http://www.haystack.demon.co.uk
> hay@haystack.demon.co.uk
> voice: +44 (0)116 271 4198
> fax: +44(0)116 271 8642
> 




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