soccer jersey forums.silverfrost.com :: View topic - Thanks for the Memory(s)
forums.silverfrost.com Forum Index forums.silverfrost.com
Welcome to the Silverfrost forums
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Thanks for the Memory(s)

 
Post new topic   Reply to topic    forums.silverfrost.com Forum Index -> 64-bit
View previous topic :: View next topic  
Author Message
LitusSaxonicum



Joined: 23 Aug 2005
Posts: 2391
Location: Yateley, Hants, UK

PostPosted: Sun Mar 12, 2017 11:48 pm    Post subject: Reply with quote

John,

If you look at the post on "Some issues with roundoff and a whole lot else", I looked at the memory capacities for self-build computer components, and most mainboards support 32Gb, but you can, for a price, get 8-socket boards with correspondingly expensive memory. My prices are in GBP.

Just about everything I want to do can be done in 1Gb, but I recognize the need of folks like Dan and John in Oz to access all the RAM they can. It seems to me that a 1D array or REAL*8 could take up 16 Gb with 2Gb elements of 8 bytes, let alone 2 or 3D arrays.

The fact that bigger than 4-byte indexing is needed in terms of bytes doesn't seem to me to need bigger than 4-byte integers for the variables. But hey, it's all academic in the sense that I'll never need to use it.

Eddie
Back to top
View user's profile Send private message
DanRRight



Joined: 10 Mar 2008
Posts: 2836
Location: South Pole, Antarctica

PostPosted: Mon Mar 13, 2017 2:59 am    Post subject: Reply with quote

John, Ask your own or any 10 years old kid in the world do they want GTX 1080ti with 11GB of RAM or not. They will ask you if you can buy two. Or three. And will perfectly explain and demonstrate why even more RAM is needed.


Same but often much worse with our modeling. The modeling world is even not 3D but more multidimensional. Remember that Fortran 77 had 7-dimensional restriction ? I suffered from that because for one task i needed 8.

With plasma PIC codes for example you need for ions 3 space dimensions, 3 momentum dimensions, 1 more for ionization state and 1 for partitioning. And that for 2-3 different elements. Total 9. Total 7 dimensions needed for electrons (they all have ionization =1). Also data needed for the EM fields: 3 for electric field, 3 for magnetic field. Do the math how many particles you can include in the simulation for realistic modeling.
Back to top
View user's profile Send private message
JohnCampbell



Joined: 16 Feb 2006
Posts: 2561
Location: Sydney

PostPosted: Mon Mar 13, 2017 5:04 am    Post subject: Reply with quote

John,
Quote:
all this is all well and good, but many folks can'r�t afford 32Gb memory computers

Times must be tough where you are !! I suggest you google memory prices. You can get 32gb DDR4 memory for about $AU 300, which is less than the price of an i7-7700K processor.

Not sure of the price in a notebook, but not much more, unless you buy from Dell or HP !!
Back to top
View user's profile Send private message
LitusSaxonicum



Joined: 23 Aug 2005
Posts: 2391
Location: Yateley, Hants, UK

PostPosted: Mon Mar 13, 2017 10:58 am    Post subject: Reply with quote

Depends what you want it for. Most Fortran programs ever written will run in 1 Gb, mainly because they were intended to run on machines with a lot less.

Eddie
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    forums.silverfrost.com Forum Index -> 64-bit All times are GMT + 1 Hour
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group