Question

在MiniGUi中，我可以看到db.index。如何通过Java代码将其设置为tree.spatial.rstarvariants.rstar.RStartTreeFactory？

我已实施：

params.addParameter(AbstractDatabase.Parameterizer.INDEX_ID,tree.spatial.rstarvariants.rstar.RStarTreeFactory);

找不到addParameter()函数tree.spatial...RStarTreeFactory类的第二个参数

// Setup parameters:
            ListParameterization params = new ListParameterization();
            params.addParameter(
                    FileBasedDatabaseConnection.Parameterizer.INPUT_ID,
                    fileLocation);
            params.addParameter(AbstractDatabase.Parameterizer.INDEX_ID,
                RStarTreeFactory.class);

我得到了NullPointerException。我是否正确使用RStarTreeFactory.class？

Answer 1

ELKI命令行（和MiniGui;它是一个命令行构建器）允许指定简写类名，省略已实现接口的包前缀。

完整的命令行文档产生：

-db.index <object_1|class_1,...,object_n|class_n>
    Database indexes to add.
    Implementing de.lmu.ifi.dbs.elki.index.IndexFactory
    Known classes (default package de.lmu.ifi.dbs.elki.index.):
    -> tree.spatial.rstarvariants.rstar.RStarTreeFactory
    -> ...

即。对于此参数，可以省略类前缀de.lmu.ifi.dbs.elki.index.。

因此完整的班级名称是：

de.lmu.ifi.dbs.elki.index.tree.spatial.rstarvariants.rstar.RStarTreeFactory

或者您只需输入RStarTreeFactory，然后让eclipse自动修复导入：

params.addParameter(AbstractDatabase.Parameterizer.INDEX_ID,
    RStarTreeFactory.class);
// Bulk loading static data yields much better trees and is much faster, too.
params.addParameter(RStarTreeFactory.Parameterizer.BULK_SPLIT_ID, 
    SortTileRecursiveBulkSplit.class);
// Page size should fit your dimensionality.
// For 2-dimensional data, use page sizes less than 1000.
// Rule of thumb: 15...20 * (dim * 8 + 4) is usually reasonable
// (for in-memory bulk-loaded trees)
params.addParameter(AbstractPageFileFactory.Parameterizer.PAGE_SIZE_ID, 300);

另请参阅：Geo Indexing example in the tutorial folder。

ELKI DBSCAN R *树索引

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