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Re: RealValued functions and derivatives

• To: mathgroup at smc.vnet.net
• Subject: [mg63406] Re: RealValued functions and derivatives
• From: "Valeri Astanoff" <astanoff at yahoo.fr>
• Date: Fri, 30 Dec 2005 02:32:25 -0500 (EST)
• References: <dojesh$fo8$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Fabrice,

Zis is my way (maybe not the best way)
to force derivative real values :

In[1]:=$Version

Out[1]=5.1 for Microsoft Windows (January 28, 2005)

In[2]:=<<Algebra`ReIm`

In[3]:=x/:Im[x]=0;
y/:Im[y]=0;
Algebra`ReIm`Private`RealValuedQ[f]^=True;
Algebra`ReIm`Private`RealValuedQ[Derivative[_,_][f]]^=True;

In[7]:=Im[Derivative[1,0][f][x,y]]

Out[7]=0

In[8]:=Im[Derivative[0,1][f][x,y]]

Out[8]=0


Et voila !

v.a.