Re: Compile. Not again
- To: mathgroup at smc.vnet.net
- Subject: [mg56490] Re: [mg56470] Compile. Not again
- From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
- Date: Tue, 26 Apr 2005 21:52:50 -0400 (EDT)
- References: <200504260534.BAA14453@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Another strange (to me) observation: consider the following function g
g = CompiledFunction[{}, {{2, 1, 0}}, {0, 4, 0, 0, 1}, {{1, 5}, {7,
{0}, 2,
1, 0}, {4, 1, 0}, {64, 0, 0, 0, 0,
1}, {4, 1, 0}, {4, 1, 2}, {24, 1, 2, 3}, {65, 0, 0, 0,
0, 3}, {2}}, Function[{}, Module[{L = {0}}, L[[1]]++; L]],
Evaluate]
g ought to be exactly the same as f (look at InputForm[f]). However
every time you evaluate g[] you will get {1} (at least I do with
Mathemaitca 5.1 on Mac OS X).
Anndrzej Kozlowski
On 26 Apr 2005, at 14:34, Maxim wrote:
> *This message was transferred with a trial version of CommuniGate(tm)
> Pro*
> Here's what I get in version 5.1.0:
>
> In[1]:= f = Compile[{}, Module[{L = {0}}, L[[1]]++; L]]
>
> In[2]:= a = f[]
>
> Out[2]= {1}
>
> In[3]:= b = f[]
>
> Out[3]= {2}
>
> In[4]:= Table[f[], {3}]
>
> Out[4]= {{5}, {5}, {5}}
>
> In[5]:= {a, b}
>
> Out[5]= {{5}, {5}}
>
> Each subsequent call to f uses the modified value of L. This also
> affects
> Table and all the objects involved in assignments such as x = f[] (but
> not
> x = f[][[1]]), including DownValues[Out]. The problem might be related
> to
> deciding whether a and b point to the same shared object.
>
> Maxim Rytin
> m.r at inbox.ru
>
- References:
- Compile. Not again
- From: Maxim <ab_def@prontomail.com>
- Compile. Not again