Re: Disappearing Function Definition
- To: mathgroup at smc.vnet.net
- Subject: [mg45011] Re: [mg45006] Disappearing Function Definition
- From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
- Date: Sat, 13 Dec 2003 06:05:54 -0500 (EST)
- References: <200312120942.EAA24199@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
All that happens is that the kenrel quits. The "definition" disappears
simply because once the kernel quits all all values and definiton
stored by Mathematica go with it. Why does the kernel quit? Presumably
because Mathematica can't make any sense of your input. I certainly
can't blame it and also I can't believe you really expected to get any
answer!
Of course if you give x a numerical value, then it's another matter:
f[x_, y_] = x + y;
Pick[x_, y_] = Sum[DiracDelta[y-t], {t, x}];
x=15;
Integrate[f[x, y]*Pick[x, y], {y, 0, 100}]
345
On 12 Dec 2003, at 18:42, Scott Guthery wrote:
> Can anybody explain the following? Note that In[4] thinks for
> a while and then returns with no Out[4] but if you then take a
> look at f its definition has disappeared.
>
>
> In[1]:= f[x_, y_] = x + y
>
> Out[1]:= x+y
>
> In[2]:= f[x,y]
>
> Out[2]:= x+y
>
> In[3]:= Pick[x_, y_] = Sum[DiracDelta[y-t], {t, x}]
>
> Out[3]:= \!\(\[Sum]\+\(t = 1\)\%x DiracDelta[\(-t\) + y]\)
>
> In[4]:= Integrate[f[x, y]*Pick[x, y], {y, 0, 100}]
>
> *** Nothing returned here ***
>
> In[1]:= f[x,y]
>
> Out[1]= f[x,y]
>
>
>
>
>
- References:
- Disappearing Function Definition
- From: "Scott Guthery" <sguthery@mobile-mind.com>
- Disappearing Function Definition