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Re: Mathematica 7 much slower than Mathematica 6 on Limit

  • To: mathgroup at smc.vnet.net
  • Subject: [mg94771] Re: [mg94767] Mathematica 7 much slower than Mathematica 6 on Limit
  • From: Syd Geraghty <sydgeraghty at me.com>
  • Date: Wed, 24 Dec 2008 06:04:41 -0500 (EST)
  • References: <200812231200.HAA26141@smc.vnet.net>

Hi WB,

Your code.

> h = 1.575; er = 4.7;er2 = (er - 1)/2;
> p[k_] := Sqrt[1 - k^2];
>
> With[{a = 0.5},
>    Limit[120 Pi EllipticK[a/d]/EllipticK[p[a/d]]/
>    Sqrt[1 + er2 EllipticK[
>    p[a/d]] EllipticK[Sinh[Pi a/2/h]/Sinh[Pi d/2/h]]/
>    EllipticK[a/d]/EllipticK[p[Sinh[Pi a/2/h]/Sinh[Pi d/2/h]]]],
>    d -> 1000]]//Timing

These are three sequential results on V7 and V5.2 on the system  
defined below my email address:


1		{102.358, 63.4524}				V7

2		{0.398885 Second, 63.4524}		V5.2

3		{0.001689, 63.4524}				V7


Strange results:

I started from fresh kernels and re-ran results in the sequence below:

4		{0.32161 Second, 63.4524}		V5.2

5		{102.669, 63.4524}				V7

6		{0.000948 Second, 63.4524}		V5.2

7		{0.002093, 63.4524}				V7


	I sent copies of my results to WRI support for them to check it out.


Cheers .... Syd


Syd Geraghty B.Sc, M.Sc.

sydgeraghty at mac.com

Mathematica 7.0.0 for Mac OS X x86 (64 - bit) (21st November, 2008)
MacOS X V 10.5.6
MacBook Pro 2.33 Ghz Intel Core 2 Duo  2GB RAM










On Dec 23, 2008, at 7:00 AM, wb at wavebounce.com wrote:

> I just updated to Mathematica 7 and here's the first Mathematica 6  
> notebook I've had any problem with. Can anyone comment on whether I  
> should make some change to speed up this routine? Surely Mathematica  
> 7 isn't 15 times slower in general.
> On my WinXP machine:
> 104.9 sec on Mathematica 7
> 8.7 sec on Mathematica 6
>
> Thanks.
> **************
> h = 1.575; er = 4.7;er2 = (er - 1)/2;
> p[k_] := Sqrt[1 - k^2];
>
> With[{a = 0.5},
>    Limit[120 Pi EllipticK[a/d]/EllipticK[p[a/d]]/
>    Sqrt[1 + er2 EllipticK[
>    p[a/d]] EllipticK[Sinh[Pi a/2/h]/Sinh[Pi d/2/h]]/
>    EllipticK[a/d]/EllipticK[p[Sinh[Pi a/2/h]/Sinh[Pi d/2/h]]]],
>    d -> 1000]]
> ****************
>



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