Skip to content Skip to navigation Skip to collection information

Connexions

You are here: Home » Content » High Performance Computing » Programs That Require More Memory Than You Have

Navigation

Table of Contents

Lenses

What is a lens?

Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags? tag icon

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

This content is ...

Endorsed by Endorsed (What does "Endorsed by" mean?)

This content has been endorsed by the organizations listed. Click each link for a list of all content endorsed by the organization.
  • HPC Open Edu Cup

    This collection is included inLens: High Performance Computing Open Education Cup 2008-2009
    By: Ken Kennedy Institute for Information Technology

    Click the "HPC Open Edu Cup" link to see all content they endorse.

Affiliated with (What does "Affiliated with" mean?)

This content is either by members of the organizations listed or about topics related to the organizations listed. Click each link to see a list of all content affiliated with the organization.
  • NSF Partnership display tagshide tags

    This collection is included inLens: NSF Partnership in Signal Processing
    By: Sidney Burrus

    Click the "NSF Partnership" link to see all content affiliated with them.

    Click the tag icon tag icon to display tags associated with this content.

  • Featured Content

    This collection is included inLens: Connexions Featured Content
    By: Connexions

    Comments:

    "The purpose of Chuck Severence's book, High Performance Computing has always been to teach new programmers and scientists about the basics of High Performance Computing. This book is for learners […]"

    Click the "Featured Content" link to see all content affiliated with them.

Also in these lenses

  • UniqU content

    This collection is included inLens: UniqU's lens
    By: UniqU, LLC

    Click the "UniqU content" link to see all content selected in this lens.

  • Lens for Engineering

    This module and collection are included inLens: Lens for Engineering
    By: Sidney Burrus

    Click the "Lens for Engineering" link to see all content selected in this lens.

  • eScience, eResearch and Computational Problem Solving

    This collection is included inLens: eScience, eResearch and Computational Problem Solving
    By: Jan E. Odegard

    Click the "eScience, eResearch and Computational Problem Solving" link to see all content selected in this lens.

Recently Viewed

This feature requires Javascript to be enabled.

Tags

(What is a tag?)

These tags come from the endorsement, affiliation, and other lenses that include this content.
 

Programs That Require More Memory Than You Have

Module by: Charles Severance, Kevin Dowd. E-mail the authors

People occasionally have programs whose memory size requirements are so great that the data can’t fit in memory all at once. At any time, some of the data has to reside outside of main memory on secondary (usually disk) storage. These out-of- core solutions fall into two categories:

  • Software-managed, out-of-core solutions
  • Virtual memory–managed, out-of-core solutions

With a software-managed approach, the programmer has recognized that the problem is too big and has modified the source code to move sections of the data out to disk for retrieval at a later time. The other method depends on the computer’s memory system handling the secondary storage requirements on its own, some- times at a great cost in runtime.

Software-Managed, Out-of-Core Solutions

Most codes with software-managed, out-of-core solutions have adjustments; you can tell the program how much memory it has to work with, and it takes care of the rest. It is important to make sure the adjustment is set correctly. Code that was tuned for a machine with limited memory could have been ported to another without taking into account the storage available. Perhaps the whole problem will fit easily.

If we are writing an out-of-core solution, the trick is to group memory references together so that they are localized. This usually occurs naturally as a side effect of partitioning, say, a matrix factorization into groups of columns. Blocking references the way we did in the previous section also corrals memory references together so you can treat them as memory “pages.” Knowing when to ship them off to disk entails being closely involved with what the program is doing.

Collection Navigation

Content actions

Download:

Collection as:

PDF | EPUB (?)

What is an EPUB file?

EPUB is an electronic book format that can be read on a variety of mobile devices.

Downloading to a reading device

For detailed instructions on how to download this content's EPUB to your specific device, click the "(?)" link.

| More downloads ...

Module as:

PDF | EPUB (?)

What is an EPUB file?

EPUB is an electronic book format that can be read on a variety of mobile devices.

Downloading to a reading device

For detailed instructions on how to download this content's EPUB to your specific device, click the "(?)" link.

| More downloads ...

Add:

Collection to:

My Favorites (?)

'My Favorites' is a special kind of lens which you can use to bookmark modules and collections. 'My Favorites' can only be seen by you, and collections saved in 'My Favorites' can remember the last module you were on. You need an account to use 'My Favorites'.

| A lens I own (?)

Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags? tag icon

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

| External bookmarks

Module to:

My Favorites (?)

'My Favorites' is a special kind of lens which you can use to bookmark modules and collections. 'My Favorites' can only be seen by you, and collections saved in 'My Favorites' can remember the last module you were on. You need an account to use 'My Favorites'.

| A lens I own (?)

Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags? tag icon

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

| External bookmarks