Granularity

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See also: Granulation (disambiguation) Granularity_sentence_0

Granularity (also called graininess), the condition of existing in granules or grains, refers to the extent to which a material or system is composed of distinguishable pieces. Granularity_sentence_1

It can either refer to the extent to which a larger entity is subdivided, or the extent to which groups of smaller indistinguishable entities have joined together to become larger distinguishable entities. Granularity_sentence_2

A kilometer broken into centimeters has finer granularity than a kilometer broken into meters; whereas, by contrast, molecules of the photographic emulsion may clump together to form distinct noticeable granules, reflecting coarser granularity. Granularity_sentence_3

Precision and ambiguity Granularity_section_0

Coarse-grained materials or systems have fewer, larger discrete components than fine-grained materials or systems. Granularity_sentence_4

Granularity_unordered_list_0

  • A coarse-grained description of a system regards large subcomponents.Granularity_item_0_0
  • A fine-grained description regards smaller components of which the larger ones are composed.Granularity_item_0_1

The concepts granularity, coarseness, and fineness are relative; and are used when comparing systems or descriptions of systems. Granularity_sentence_5

An example of increasingly fine granularity: a list of nations in the United Nations, a list of all states/provinces in those nations, a list of all cities in those states, etc. Granularity_sentence_6

Note that, although the modifying terms, fine and coarse are used consistently across all fields, the term granularity is not. Granularity_sentence_7

Granularity_unordered_list_1

  • In investing: more granularity refers to more positions of smaller size.Granularity_item_1_2
  • In photography: more granular photographic film has fewer and larger chemical "grains" (similarly, more granular sugar has fewer and larger grains).Granularity_item_1_3

Physics Granularity_section_1

A fine-grained description of a system is a detailed, exhaustive, low-level model of it. Granularity_sentence_8

A coarse-grained description is a model where some of this fine detail has been smoothed over or averaged out. Granularity_sentence_9

The replacement of a fine-grained description with a lower-resolution coarse-grained model is called coarse-graining. Granularity_sentence_10

(See for example the second law of thermodynamics) Granularity_sentence_11

Molecular dynamics Granularity_section_2

In molecular dynamics, coarse graining consists of replacing an atomistic description of a biological molecule with a lower-resolution coarse-grained model that averages or smooths away fine details. Granularity_sentence_12

Coarse-grained models have been developed for investigating the longer time- and length-scale dynamics that are critical to many biological processes, such as lipid membranes and proteins. Granularity_sentence_13

These concepts not only apply to biological molecules but also inorganic molecules. Granularity_sentence_14

Coarse graining may remove certain degrees of freedom, such as the vibrational modes between two atoms, or represent the two atoms as a single particle. Granularity_sentence_15

The ends to which systems may be coarse-grained is simply bound by the accuracy in the dynamics and structural properties one wishes to replicate. Granularity_sentence_16

This modern area of research is in its infancy, and although it is commonly used in biological modeling, the analytic theory behind it is poorly understood. Granularity_sentence_17

Computing Granularity_section_3

See also: granularity (parallel computing) Granularity_sentence_18

In parallel computing, granularity means the amount of computation in relation to communication, i.e., the ratio of computation to the amount of communication. Granularity_sentence_19

Fine-grained parallelism means individual tasks are relatively small in terms of code size and execution time. Granularity_sentence_20

The data is transferred among processors frequently in amounts of one or a few memory words. Granularity_sentence_21

Coarse-grained is the opposite: data is communicated infrequently, after larger amounts of computation. Granularity_sentence_22

The finer the granularity, the greater the potential for parallelism and hence speed-up, but the greater the overheads of synchronization and communication. Granularity_sentence_23

In order to attain the best parallel performance, the best balance between load and communication overhead needs to be found. Granularity_sentence_24

If the granularity is too fine, the performance can suffer from the increased communication overhead. Granularity_sentence_25

On the other side, if the granularity is too coarse, the performance can suffer from load imbalance. Granularity_sentence_26

Reconfigurable computing and supercomputing Granularity_section_4

See also: Embedded Supercomputing Granularity_sentence_27

In reconfigurable computing and in supercomputing these terms refer to the data path width. Granularity_sentence_28

The use of about one-bit wide processing elements like the configurable logic blocks (CLBs) in an FPGA is called fine-grained computing or fine-grained reconfigurability, whereas using wide data paths, such as, for instance, 32 bits wide resources, like microprocessor CPUs or data-stream-driven data path units (DPUs) like in a reconfigurable datapath array (rDPA) is called coarse-grained computing or coarse-grained reconfigurability. Granularity_sentence_29

Data granularity Granularity_section_5

Credits to the contents of this page go to the authors of the corresponding Wikipedia page: en.wikipedia.org/wiki/Granularity.