Re: RandomReal gets stuck
- To: mathgroup at smc.vnet.net
- Subject: [mg100361] Re: RandomReal gets stuck
- From: Szabolcs <szhorvat at gmail.com>
- Date: Tue, 2 Jun 2009 06:40:55 -0400 (EDT)
- References: <gvq0eu$n31$1@smc.vnet.net> <gvtmeb$gdh$1@smc.vnet.net>
On May 31, 1:33 pm, "Sjoerd C. de Vries" <sjoerd.c.devr... at gmail.com> wrote: > Hi Bas, > > I can confirm this bug. > > Executing an even simpler version, namely > > Maximize[Plus @@ Table[y[i], {i, 31}], Table[y[i], {i, 31}]]; > > will also set the random generator to a fixed starting point. The > number 31 is crucial, as lower values do not appear to cause the bug, > while higher values do. Changing Plus to Times appears to prevent the > bug. > > In[394]:= Table[ > Maximize[Plus @@ Table[y[i], {i, 31}], Table[y[i], {i, 31}]]; > RandomReal[], > {20} > ] > > During evaluation of In[394]:= Maximize::natt: The maximum is not > attained at any point satisfying the given constraints. >> > > Out[394]= {0.455719, 0.455719, 0.455719, 0.455719, 0.455719, \ > 0.455719, 0.455719, 0.455719, 0.455719, 0.455719, 0.455719, 0.455719, > \ > 0.455719, 0.455719, 0.455719, 0.455719, 0.455719, 0.455719, 0.455719, > \ > 0.455719} > > This is very nasty, as a lot of people critically depend on random > functions to be random. I would urge you to report this to wolfram > support. > The problem is present both in version 6.0.3 and version 7.0.1.