Re: Another Out of Memory Problem

*To*: mathgroup at smc.vnet.net*Subject*: [mg91331] Re: Another Out of Memory Problem*From*: Roland Franzius <roland.franzius at uos.de>*Date*: Sat, 16 Aug 2008 05:53:17 -0400 (EDT)*References*: <g8137j$19$1@smc.vnet.net>

Kevin J. McCann schrieb: > I can do the following: > > Integrate[Cos[2*x]* > Exp[I*z*Cos[x]], > {x, -Pi, Pi}] > > > which produces a Bessel function answer; however if I change the > argument in the cosine to 2.5 as in: > > Integrate[Cos[2.5*x]* > Exp[I*z*Cos[x]], > {x, -Pi, Pi}] > > I almost immediately get this: > > No more memory available. > Mathematica kernel has shut down. > Try quitting other applications and then retry. > > Any ideas why? I am running XP with 2Gb of memory. Start the task manager (Alt+Ctrl+Del) and keep track of the memory in use. Windows class A Mathematica is able to adress 2 GB of memory maximally. Since it is running atop the Windows Desktop it is not able to issue the "out of memory" warning because of lack of memory in its own adress space, the old windows blue screen trap. With a machine that is able to adress 3 GB the warning is issued. With a 2 GB machine it is a question of how much memory is allocated for the graphics system. With less than 2 GB available the kernel crases on memory overflow. Integrate[Cos[2.5`20*x]*Exp[I*z*Cos[x]], {x, -Pi, Pi}] consumes about 1GB maximum of memory while Integrate[Cos[2.5*x]*Exp[I*z*Cos[x]], {x, -Pi, Pi}] needs around 1.97 GB and begins to block the task manager as well as the windows event handler. Its difficult to reach the Abort menu activation 2 GB intel dual core Windows Vista system. -- Roland Franzius