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Commander Kinsey
Guest
Why do graphics cards only monitor the speed of one fan? If the other one fails, it won\'t know!
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G
Gerhard Hoffmann
Guest
Am 14.07.20 um 17:50 schrieb bitrex:
No. Inverting the conductivity matrix is hard because you
cannot do the pivoting in advance. The necessity shows
up during work.
For transient analysis, every time step builds on the previous one(s)
and you cannot parallelize a lot of them because you don\'t know
the starting condition of the future ones.
It has been tried often, a working solution would have been worth gold.
I remember the Weitek array coprocessor back in 80386 times and
a try with the NS16032. They never got a factor of more than 2 or 3.
Everything really interesting is np-complete. :-(
Cheers, Gerhard
I suggested to Mike E that LT Spice should use a graphic card for
computation, but I guess that\'s not going to happen now.
A modest Windows PC can spin Solidworks 3D images around just fine.
Is SPICE trivially parallelize-able in that way?
No. Inverting the conductivity matrix is hard because you
cannot do the pivoting in advance. The necessity shows
up during work.
For transient analysis, every time step builds on the previous one(s)
and you cannot parallelize a lot of them because you don\'t know
the starting condition of the future ones.
It has been tried often, a working solution would have been worth gold.
I remember the Weitek array coprocessor back in 80386 times and
a try with the NS16032. They never got a factor of more than 2 or 3.
Everything really interesting is np-complete. :-(
Cheers, Gerhard
B
bitrex
Guest
On 7/14/2020 12:14 PM, Gerhard Hoffmann wrote:
That\'s what I figured.
There are probably ways to leverage GPUs in the process somehow but I
expect it\'s going to be a 3 or 4 times speedup over using a general
purpose CPU not like a ten thousand times speedup in the way rendering
scenes is.
Am 14.07.20 um 17:50 schrieb bitrex:
I suggested to Mike E that LT Spice should use a graphic card for
computation, but I guess that\'s not going to happen now.
A modest Windows PC can spin Solidworks 3D images around just fine.
Is SPICE trivially parallelize-able in that way?
No. Inverting the conductivity matrix is hard because you
cannot do the pivoting in advance. The necessity shows
up during work.
For transient analysis, every time step builds on the previous one(s)
and you cannot parallelize a lot of them because you don\'t know
the starting condition of the future ones.
It has been tried often, a working solution would have been worth gold.
I remember the Weitek array coprocessor back in 80386 times and
a try with the NS16032. They never got a factor of more than 2 or 3.
Everything really interesting is np-complete. :-(
Cheers, Gerhard
That\'s what I figured.
There are probably ways to leverage GPUs in the process somehow but I
expect it\'s going to be a 3 or 4 times speedup over using a general
purpose CPU not like a ten thousand times speedup in the way rendering
scenes is.
B
bitrex
Guest
On 7/14/2020 12:14 PM, Gerhard Hoffmann wrote:
Another problem of practical value that\'s NP-complete is the pen-plotter
problem or the \"postal-route inspection\" problem; how do you connect
vertices of a vector image with lines such that the total Manhattan
distance the plotter head covers in the process is minimal.
as opposed to the shortest path problem on directed and directed graphs,
exact solution to that one is np-complete. There are heuristics that do
pretty good
Am 14.07.20 um 17:50 schrieb bitrex:
I suggested to Mike E that LT Spice should use a graphic card for
computation, but I guess that\'s not going to happen now.
A modest Windows PC can spin Solidworks 3D images around just fine.
Is SPICE trivially parallelize-able in that way?
No. Inverting the conductivity matrix is hard because you
cannot do the pivoting in advance. The necessity shows
up during work.
For transient analysis, every time step builds on the previous one(s)
and you cannot parallelize a lot of them because you don\'t know
the starting condition of the future ones.
It has been tried often, a working solution would have been worth gold.
I remember the Weitek array coprocessor back in 80386 times and
a try with the NS16032. They never got a factor of more than 2 or 3.
Everything really interesting is np-complete. :-(
Cheers, Gerhard
Another problem of practical value that\'s NP-complete is the pen-plotter
problem or the \"postal-route inspection\" problem; how do you connect
vertices of a vector image with lines such that the total Manhattan
distance the plotter head covers in the process is minimal.
as opposed to the shortest path problem on directed and directed graphs,
exact solution to that one is np-complete. There are heuristics that do
pretty good
B
bitrex
Guest
On 7/14/2020 12:25 PM, bitrex wrote:
it\'s similar but distinct from the traveling salesman problem
On 7/14/2020 12:14 PM, Gerhard Hoffmann wrote:
Am 14.07.20 um 17:50 schrieb bitrex:
I suggested to Mike E that LT Spice should use a graphic card for
computation, but I guess that\'s not going to happen now.
A modest Windows PC can spin Solidworks 3D images around just fine.
Is SPICE trivially parallelize-able in that way?
No. Inverting the conductivity matrix is hard because you
cannot do the pivoting in advance. The necessity shows
up during work.
For transient analysis, every time step builds on the previous one(s)
and you cannot parallelize a lot of them because you don\'t know
the starting condition of the future ones.
It has been tried often, a working solution would have been worth gold.
I remember the Weitek array coprocessor back in 80386 times and
a try with the NS16032. They never got a factor of more than 2 or 3.
Everything really interesting is np-complete. :-(
Cheers, Gerhard
Another problem of practical value that\'s NP-complete is the pen-plotter
problem or the \"postal-route inspection\" problem; how do you connect
vertices of a vector image with lines such that the total Manhattan
distance the plotter head covers in the process is minimal.
as opposed to the shortest path problem on directed and directed graphs,
exact solution to that one is np-complete. There are heuristics that do
pretty good
it\'s similar but distinct from the traveling salesman problem
S
server
Guest
On Tue, 14 Jul 2020 18:14:04 +0200, Gerhard Hoffmann <dk4xp@arcor.de>
wrote:
LT Spice can already use multiple cores, so something is
parallel-izable. The petaflop computers, used for weather and physics
simulation, have thousands of CPUs.
Spice is usually fine, but once in a while I want 1000x or so more
speed.
--
John Larkin Highland Technology, Inc
Science teaches us to doubt.
Claude Bernard
wrote:
Am 14.07.20 um 17:50 schrieb bitrex:
I suggested to Mike E that LT Spice should use a graphic card for
computation, but I guess that\'s not going to happen now.
A modest Windows PC can spin Solidworks 3D images around just fine.
Is SPICE trivially parallelize-able in that way?
No. Inverting the conductivity matrix is hard because you
cannot do the pivoting in advance. The necessity shows
up during work.
For transient analysis, every time step builds on the previous one(s)
and you cannot parallelize a lot of them because you don\'t know
the starting condition of the future ones.
It has been tried often, a working solution would have been worth gold.
I remember the Weitek array coprocessor back in 80386 times and
a try with the NS16032. They never got a factor of more than 2 or 3.
Everything really interesting is np-complete. :-(
Cheers, Gerhard
LT Spice can already use multiple cores, so something is
parallel-izable. The petaflop computers, used for weather and physics
simulation, have thousands of CPUs.
Spice is usually fine, but once in a while I want 1000x or so more
speed.
--
John Larkin Highland Technology, Inc
Science teaches us to doubt.
Claude Bernard
B
bitrex
Guest
On 7/14/2020 12:27 PM, jlarkin@highlandsniptechnology.com wrote:
GPU cores aren\'t general-purpose CPUs, they\'re serial-pipelined and
optimized for SIMD-instructions.
A mutlicore general-purpose CPU has good cache coherency there\'s a fast
on-die cache for all 4 or 8 cores or w/e that any of the processors can
look at data the others are working on quickly.
It\'s hard to achieve that kind of cache coherency with thousands of
cores. If core #127 needs to \"see\" what core #562 is working on it
usually has to go out to video RAM. which is not nearly as fast as
on-die cache.
On Tue, 14 Jul 2020 18:14:04 +0200, Gerhard Hoffmann <dk4xp@arcor.de
wrote:
Am 14.07.20 um 17:50 schrieb bitrex:
I suggested to Mike E that LT Spice should use a graphic card for
computation, but I guess that\'s not going to happen now.
A modest Windows PC can spin Solidworks 3D images around just fine.
Is SPICE trivially parallelize-able in that way?
No. Inverting the conductivity matrix is hard because you
cannot do the pivoting in advance. The necessity shows
up during work.
For transient analysis, every time step builds on the previous one(s)
and you cannot parallelize a lot of them because you don\'t know
the starting condition of the future ones.
It has been tried often, a working solution would have been worth gold.
I remember the Weitek array coprocessor back in 80386 times and
a try with the NS16032. They never got a factor of more than 2 or 3.
Everything really interesting is np-complete. :-(
Cheers, Gerhard
LT Spice can already use multiple cores, so something is
parallel-izable. The petaflop computers, used for weather and physics
simulation, have thousands of CPUs.
Spice is usually fine, but once in a while I want 1000x or so more
speed.
GPU cores aren\'t general-purpose CPUs, they\'re serial-pipelined and
optimized for SIMD-instructions.
A mutlicore general-purpose CPU has good cache coherency there\'s a fast
on-die cache for all 4 or 8 cores or w/e that any of the processors can
look at data the others are working on quickly.
It\'s hard to achieve that kind of cache coherency with thousands of
cores. If core #127 needs to \"see\" what core #562 is working on it
usually has to go out to video RAM. which is not nearly as fast as
on-die cache.
B
bitrex
Guest
On 7/14/2020 12:27 PM, jlarkin@highlandsniptechnology.com wrote:
GPU cores aren\'t general-purpose CPUs, they\'re serial-pipelined and
optimized for SIMD-instructions.
A mutlicore general-purpose CPU has good cache coherency there\'s a fast
on-die cache for all 4 or 8 cores or w/e that any of the processors can
look at data the others are working on quickly.
It\'s hard to achieve that kind of cache coherency with thousands of
cores. If core #127 needs to \"see\" what core #562 is working on it
usually has to go out to video RAM. which is not nearly as fast as
on-die cache.
On Tue, 14 Jul 2020 18:14:04 +0200, Gerhard Hoffmann <dk4xp@arcor.de
wrote:
Am 14.07.20 um 17:50 schrieb bitrex:
I suggested to Mike E that LT Spice should use a graphic card for
computation, but I guess that\'s not going to happen now.
A modest Windows PC can spin Solidworks 3D images around just fine.
Is SPICE trivially parallelize-able in that way?
No. Inverting the conductivity matrix is hard because you
cannot do the pivoting in advance. The necessity shows
up during work.
For transient analysis, every time step builds on the previous one(s)
and you cannot parallelize a lot of them because you don\'t know
the starting condition of the future ones.
It has been tried often, a working solution would have been worth gold.
I remember the Weitek array coprocessor back in 80386 times and
a try with the NS16032. They never got a factor of more than 2 or 3.
Everything really interesting is np-complete. :-(
Cheers, Gerhard
LT Spice can already use multiple cores, so something is
parallel-izable. The petaflop computers, used for weather and physics
simulation, have thousands of CPUs.
Spice is usually fine, but once in a while I want 1000x or so more
speed.
GPU cores aren\'t general-purpose CPUs, they\'re serial-pipelined and
optimized for SIMD-instructions.
A mutlicore general-purpose CPU has good cache coherency there\'s a fast
on-die cache for all 4 or 8 cores or w/e that any of the processors can
look at data the others are working on quickly.
It\'s hard to achieve that kind of cache coherency with thousands of
cores. If core #127 needs to \"see\" what core #562 is working on it
usually has to go out to video RAM. which is not nearly as fast as
on-die cache.
B
bitrex
Guest
On 7/14/2020 12:27 PM, jlarkin@highlandsniptechnology.com wrote:
People with advanced credentials in e.g. meteorology or computational
biology or physics plus the computer science of optimizing
multiprocessing systems get paid the biggo buckos
On Tue, 14 Jul 2020 18:14:04 +0200, Gerhard Hoffmann <dk4xp@arcor.de
wrote:
Am 14.07.20 um 17:50 schrieb bitrex:
I suggested to Mike E that LT Spice should use a graphic card for
computation, but I guess that\'s not going to happen now.
A modest Windows PC can spin Solidworks 3D images around just fine.
Is SPICE trivially parallelize-able in that way?
No. Inverting the conductivity matrix is hard because you
cannot do the pivoting in advance. The necessity shows
up during work.
For transient analysis, every time step builds on the previous one(s)
and you cannot parallelize a lot of them because you don\'t know
the starting condition of the future ones.
It has been tried often, a working solution would have been worth gold.
I remember the Weitek array coprocessor back in 80386 times and
a try with the NS16032. They never got a factor of more than 2 or 3.
Everything really interesting is np-complete. :-(
Cheers, Gerhard
LT Spice can already use multiple cores, so something is
parallel-izable. The petaflop computers, used for weather and physics
simulation, have thousands of CPUs.
Spice is usually fine, but once in a while I want 1000x or so more
speed.
People with advanced credentials in e.g. meteorology or computational
biology or physics plus the computer science of optimizing
multiprocessing systems get paid the biggo buckos
B
bitrex
Guest
On 7/14/2020 12:27 PM, jlarkin@highlandsniptechnology.com wrote:
People with advanced credentials in e.g. meteorology or computational
biology or physics plus the computer science of optimizing
multiprocessing systems get paid the biggo buckos
On Tue, 14 Jul 2020 18:14:04 +0200, Gerhard Hoffmann <dk4xp@arcor.de
wrote:
Am 14.07.20 um 17:50 schrieb bitrex:
I suggested to Mike E that LT Spice should use a graphic card for
computation, but I guess that\'s not going to happen now.
A modest Windows PC can spin Solidworks 3D images around just fine.
Is SPICE trivially parallelize-able in that way?
No. Inverting the conductivity matrix is hard because you
cannot do the pivoting in advance. The necessity shows
up during work.
For transient analysis, every time step builds on the previous one(s)
and you cannot parallelize a lot of them because you don\'t know
the starting condition of the future ones.
It has been tried often, a working solution would have been worth gold.
I remember the Weitek array coprocessor back in 80386 times and
a try with the NS16032. They never got a factor of more than 2 or 3.
Everything really interesting is np-complete. :-(
Cheers, Gerhard
LT Spice can already use multiple cores, so something is
parallel-izable. The petaflop computers, used for weather and physics
simulation, have thousands of CPUs.
Spice is usually fine, but once in a while I want 1000x or so more
speed.
People with advanced credentials in e.g. meteorology or computational
biology or physics plus the computer science of optimizing
multiprocessing systems get paid the biggo buckos
P
Phil Hobbs
Guest
On 2020-07-14 12:14, Gerhard Hoffmann wrote:
It probably could be, if you changed the scheme so as to impose a
speed-of-light propagation limit. That way you could divide the
schematic up into chunks, do time steps locally, and then propagate the
changes to adjacent chunks.
That gets rid of every node having to know about every other node on
every time step, and makes FDTD codes such as my POEMS facility
parallelize well. (It works that way.)
Linear algebra also can be made to vectorize well on the right hardware.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com
Am 14.07.20 um 17:50 schrieb bitrex:
I suggested to Mike E that LT Spice should use a graphic card for
computation, but I guess that\'s not going to happen now.
A modest Windows PC can spin Solidworks 3D images around just fine.
Is SPICE trivially parallelize-able in that way?
No. Inverting the conductivity matrix is hard because you
cannot do the pivoting in advance. The necessity shows
up during work.
For transient analysis, every time step builds on the previous one(s)
and you cannot parallelize a lot of them because you don\'t know
the starting condition of the future ones.
It has been tried often, a working solution would have been worth gold.
I remember the Weitek array coprocessor back in 80386 times and
a try with the NS16032. They never got a factor of more than 2 or 3.
Everything really interesting is np-complete. :-(
Cheers, Gerhard
It probably could be, if you changed the scheme so as to impose a
speed-of-light propagation limit. That way you could divide the
schematic up into chunks, do time steps locally, and then propagate the
changes to adjacent chunks.
That gets rid of every node having to know about every other node on
every time step, and makes FDTD codes such as my POEMS facility
parallelize well. (It works that way.)
Linear algebra also can be made to vectorize well on the right hardware.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com