Re: using predefined expressions in functions [newbie question]
- To: mathgroup at smc.vnet.net
- Subject: [mg100219] Re: using predefined expressions in functions [newbie question]
- From: Alexei Boulbitch <Alexei.Boulbitch at iee.lu>
- Date: Thu, 28 May 2009 06:49:51 -0400 (EDT)
Hi, ChangMo,
Try to determine the function explicitly in terms of its arguments like one of the following:
f1[R1_, R2_] := R1.R2;
In[17]:= f1[{1, 2, 3}, {4, 5, 6}]
Out[17]= 32
or otherwise,
f2[x1_, y1_, z1_, x2_, y2_, z2_] := x1*x2 + y1*y2 + z1*z2;
In[25]:= f[1, 2, 3, 4, 5, 6]
Out[25]= 32
or like this:
In[35]:=
f[x1_, y1_, z1_, x2_, y2_, z2_] := {x1, y1, z1}.{x2, y2, z2};
f[1, 2, 3, 4, 5, 6]
Out[36]= 32
Hi,
I've been trying to write a function using some predefined
expressions, but the function assignment seems to understand the
symbols in the expressions as literals. eg.,
Needs["VectorAnalysis`"]
R1 := {x1,y1,z1}
R2 := {x2,y2,z2}
f[x1_,y1_,z1_,x2_,y2_,z2_] := R1 . R2
f[1,2,3,4,5,6]
gives the output
x1 x2 + y1 y2 + z1 z2
instead of
32 ( = 1*4 + 2*5 + 3*6 )
Can anyone help me with this? Thanks for your attention.
-ChangMo
--
Alexei Boulbitch, Dr., habil.
Senior Scientist
IEE S.A.
ZAE Weiergewan
11, rue Edmond Reuter
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Luxembourg
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