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In mathematics, a Euclidean distance matrix is an ''n×n'' matrix representing the spacing of a set of ''n'' points in Euclidean space. If ''A'' is a Euclidean distance matrix and the points are defined on ''m''-dimensional space, then the elements of ''A'' are given by : where ||.||2 denotes the 2-norm on Rm. ==Properties== Simply put, the element describes the square of the distance between the ''i'' th and ''j'' th points in the set. By the properties of the 2-norm (or indeed, Euclidean distance in general), the matrix ''A'' has the following properties. * All elements on the diagonal of ''A'' are zero (i.e. it is a hollow matrix). * The trace of ''A'' is zero (by the above property). * ''A'' is symmetric (i.e. ). * * The number of unique (distinct) non-zero values within an ''n''-by-''n'' Euclidean distance matrix is bounded above by due to the matrix being symmetric and hollow. * In dimension ''m'', a Euclidean distance matrix has rank less than or equal to ''m+2''. If the points are in general position, the rank is exactly 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「Euclidean distance matrix」の詳細全文を読む スポンサード リンク
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