Rapid KNN retrieval method and system for high-dimensional metric spatial data
A spatial data, high-dimensional technology, applied in the field of high-dimensional spatial data retrieval, can solve the problems of large data volume and low query efficiency, and achieve the effect of high recall rate and fast retrieval speed
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Embodiment 1
[0029] see figure 1 , the fast KNN retrieval method of the high-dimensional dimensional space data of the present embodiment, comprises the following steps:
[0030] S110. Obtain a query instruction, including query data, nearest neighbor K value, and default query radius r.
[0031] S120. Acquire a current node, where the current node includes at least one child node.
[0032] S130. Prune the child nodes of the current node from top to bottom until leaf nodes.
[0033] S140. Traverse the leaf nodes, obtain K nearest neighbor data, obtain the distance d of the Kth data farthest from the queried data, and update the query radius r=d.
[0034] S150. Take the parent node of the current node as the new current node, and execute step S120.
[0035] S160. The current node has no sibling nodes satisfying the pruning condition, sorting from small to large and returning K nearest neighbor results.
Embodiment 2
[0037] see figure 2 , the fast KNN retrieval method of the high-dimensional dimensional space data of the present embodiment, comprises the following steps:
[0038] S201. Input query data q and default query radius r.
[0039] S202. Calculate the distance from the query data q to the supporting point sequence p[0,...,n-1], and obtain the distance sequence Pd[0,...,n-1] between q and each supporting point; Pivot Point , can be understood as a reference point, and each data will get its position in multidimensional space relative to multiple support points.
[0040] S203. Sort Pd[0,...,n-1] according to increasing distance, and obtain the storage path Ps[0,...,n-1] where the query data q belongs to the leaf node. The data storage structure is as follows image 3 As shown; for example, when the calculated sequence is Ps[1,0,11,10,...], since there are 4 layers of B+Tree in the figure, the corresponding leaf can be found by matching the first four numbers in the sequence Node...
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