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MathGroup Archive 2004

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Re: newbie question on functions

  • To: mathgroup at smc.vnet.net
  • Subject: [mg51763] Re: [mg51750] newbie question on functions
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Mon, 1 Nov 2004 02:52:44 -0500 (EST)
  • Reply-to: hanlonr at cox.net
  • Sender: owner-wri-mathgroup at wolfram.com

Functional programming would be simpler.

ratio[mat_?MatrixQ, col1_Integer, col2_Integer] := 
    (Log[2,#[[1]]/#[[2]]]& /@ mat[[All,{col1,col2}]]) /; 
      1<=col1<=Length[mat[[1]]] && 1<=col2 <= Length[mat[[1]]];

intensity[mat_?MatrixQ, col1_Integer, col2_Integer] := 
    (Log[2,#[[1]]*#[[2]]]& /@ mat[[All,{col1,col2}]]) /; 
      1<=col1<=Length[mat[[1]]] && 1<=col2 <= Length[mat[[1]]];

fmicroarray=Array[fma,{3,19}];

ratio[fmicroarray,18,19]

{Log[fma[1, 18]/fma[1, 19]]/Log[2], Log[fma[2, 18]/fma[2, 19]]/Log[2], 
  Log[fma[3, 18]/fma[3, 19]]/Log[2]}

intensity[fmicroarray,18,19]

{Log[fma[1, 18]*fma[1, 19]]/Log[2], Log[fma[2, 18]*fma[2, 19]]/Log[2], 
  Log[fma[3, 18]*fma[3, 19]]/Log[2]}


Bob Hanlon

> 
> From: Todd Allen <genesplicer28 at yahoo.com>
To: mathgroup at smc.vnet.net
> Date: 2004/10/31 Sun AM 01:17:36 EST
> To: mathgroup at smc.vnet.net
> Subject: [mg51763] [mg51750] newbie question on  functions
> 
> Hi all,
>  
>      I have what is probably a nieve question, but it is giving me some 
difficulty.  I am trying to generate a function in which I pass two columns of 
information from a matrix to this function to perform some calculations.  I 
can successfully pass the data and get the resulting calculation......but the 
problem is the function returns the results but does not save the results in 
memory to perform subsequent calculations with.  How can I get the function 
to keep the result?  Is there a way to assign the function output to a new 
variable before mathematica discards the results.  Does this behavior have 
anything to do with the Head of the function  being symbolic, rather than say 
a list??
>  
> Below is the relevant code:
>  
> SetAttributes[ratio,Listable];
> SetAttributes[intensity,Listable];
> 
> ratio[cy3_,cy5_]:=Table[Log[2,(cy3/cy5)]]//N;
> intensity[cy3_,cy5_]:=Table[Log[2,(cy3*cy5)]]//N;
> ratio[Table[fmicroarray[[i,18]],{i,1,Length[fmicroarray]}],
>   Table[fmicroarray[[i,19]],{i,1,Length[fmicroarray]}]]
>  
>  
> I appreciate any insight you might have.  Thanks.
>  
> Todd
> 
> 


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