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Granularity is the extent to which a material or system is composed of distinguishable pieces or ''grains''. 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. For example, a kilometer broken into centimeters has finer granularity than a kilometer broken into meters. In contrast, molecules of photographic emulsion may clump together to form distinct noticeable granules, reflecting coarser granularity. Coarse-grained materials or systems have fewer, larger discrete components than fine-grained materials or systems. A coarse-grained description of a system regards large subcomponents while a fine-grained description regards smaller components of which the larger ones are composed. The terms granularity, coarse, and fine are relative, used when comparing systems or descriptions of systems. 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. The terms ''fine'' and ''coarse'' are used consistently across fields, but the term ''granularity'' itself is not. For example, in investing, ''more granularity'' refers to more positions of smaller size, while photographic film that is ''more granular'' has fewer and larger chemical "grains." Similarly, sugar that is ''more granular'' has fewer and larger grains. ==Physics== A ''fine-grained'' description of a system is a detailed, exhaustive, low-level model of it. A ''coarse-grained'' description is a model where some of this fine detail has been smoothed over or averaged out. The replacement of a fine-grained description with a lower-resolution coarse-grained model is called ''coarse graining''. (See for example the second law of thermodynamics) 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「granularity」の詳細全文を読む スポンサード リンク
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