utterly confused by Lightweight Grid

[Sjoerd C. de Vries]

Hi all,

I read the announcement about the new gridMathematica stuff. As a
premier licensee I got to download the Lightweight Grid Manager for
free. Cool! The documentation and the announcement were a bit
confusing as to what precisely I could do with it, but it seemed that
I would be able to run parallel calculations on my computers running
v7. So, I downloaded a PC and mac version of the Lightweight Grid
Manager and installed it on a mac and two PCs. One PC and the mac are
laptops which connect by WLAN, the other PC is wired into the LAN.

Using the web browser interface I could interact with all three
machines. So, networking seemed to be OK. The PCs can share files and
ping ok. Lightweight Grid is enabled. In Mathematica's Parallel kernel
configuration I can see two of the three servers, one PC and one mac.
The other PC remains hidden even after switching off all firewalls.
And again, the web interface runs fine, therefore I don't think that
was a factor after all.

I did not suceeded in launching any remote kernel. ParallelEvaluate
[$MachineName] returns {}.

Anyone else done some testing? Is my interpretation of Lightweight
Grid Manager's functionality mistaken and do I need some additional
stuff like the Grid server?

Cheers -- Sjoerd

[jo...@wolfram.co.uk]

On Mar 21, 10:17 am, "Sjoerd C. de Vries" <sjoerd.c.devr...@gmail.com>
wrote:

Wolfram Lightweight Grid provides a mechanism for broadcasting the
availability of a computer, and managing remote launching and
connection of available Mathematica Kernels. But it does not, itself,
include any additional Mathematica licenses.

If you have a network license of Mathematica available to you,
configure those Wolfram Lightweight Grid installations to request
licenses from your existing MathLM server.

If you do not have any available Mathematica licenses to run on those
machines, you will need to purchase some. Either a regular Mathematica
network license, or gridMathematica Server, depending on whether you
want them to also work standalone or just want them for parallel
computations.

Jon McLoone

[Vince]

> Jon McLoone- Hide quoted text -
>
> - Show quoted text -

Licenses aside, three related questions:

1. Does Wolfram Lightweight Grid contain a copy of Mathematica 7.0.1?
2. If so, is that the media it uses to provide a "computation" kernel?
3. If so, can this be incompatible with a master kernel and/or other
computation kernels at version 7.0.0?

Thank you,

Vince Virgilio

[Jon McLoone]

On Mar 25, 10:45 am, Vince <blues...@gmail.com> wrote:

> Licenses aside, three related questions:
>
> 1. Does Wolfram Lightweight Grid contain a copy of Mathematica 7.0.1?

Yes. It includes the binaries of Mathematica 7.0.1.

> 2. If so, is that the media it uses to provide a "computation" kernel?

By default, yes. But there is a way to configure it launch from
another path, which might, for example be your 7.0.0 install.

> 3. If so, can this be incompatible with a master kernel and/or other
> computation kernels at version 7.0.0?

I don't beleive that there should be any problems. Except, of course,
if you distribute a problem where there was a fix/change in 7.0.1, the
result that you got might be somewhat non-deterministic depending on
which kernel performed the calculation.

For example
ParallelEvaluate[$ReleaseNumber]
Would give a somewhat unpredicable list of 0s and 1s if you had a
mixed grid of 7.0.1 and 7.0.0 binaries.

In general, I would recommend upgrading all of your installs to 7.0.1
anyway.

Jon

[jfk4...@gmail.com]

On Mar 25, 5:45 am, Vince <blues...@gmail.com> wrote:
> Licenses aside, three related questions:
>
> 1. Does Wolfram Lightweight Grid contain a copy of Mathematica 7.0.1?

Yes.

> 2. If so, is that the media it uses to provide a "computation" kernel?

Yes. You can also configure it to launch kernels from other
Mathematica installations on the same computer. Under the Kernel
Settings tab in the web interface, change the path in KernelCommand to
another installation, e.g. a Mathematica 7.0.0 installation.

> 3. If so, can this be incompatible with a master kernel and/or other
> computation kernels at version 7.0.0?

We recommend you use 7.0.1 for the master kernel, but you can also use
7.0.0 for that. On the server side, Lightweight Grid Manager will
happily launch kernels from 6.0, 7.0.0, or 7.0.1.