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  2. Data orientation - Wikipedia

    en.wikipedia.org/wiki/Data_orientation

    The two most common representations are column-oriented (columnar format) and row-oriented (row format). [ 1 ] [ 2 ] The choice of data orientation is a trade-off and an architectural decision in databases , query engines, and numerical simulations. [ 1 ]

  3. Inverted index - Wikipedia

    en.wikipedia.org/wiki/Inverted_index

    In computer science, an inverted index (also referred to as a postings list, postings file, or inverted file) is a database index storing a mapping from content, such as words or numbers, to its locations in a table, or in a document or a set of documents (named in contrast to a forward index, which maps from documents to content). [1]

  4. Word2vec - Wikipedia

    en.wikipedia.org/wiki/Word2vec

    Arora et al. (2016) [25] explain word2vec and related algorithms as performing inference for a simple generative model for text, which involves a random walk generation process based upon loglinear topic model. They use this to explain some properties of word embeddings, including their use to solve analogies.

  5. Data analysis - Wikipedia

    en.wikipedia.org/wiki/Data_analysis

    The data is necessary as inputs to the analysis, which is specified based upon the requirements of those directing the analytics (or customers, who will use the finished product of the analysis). [ 14 ] [ 15 ] The general type of entity upon which the data will be collected is referred to as an experimental unit (e.g., a person or population of ...

  6. Raising and lowering indices - Wikipedia

    en.wikipedia.org/wiki/Raising_and_lowering_indices

    Concretely, in the case where the vector space has an inner product, in matrix notation these can be thought of as row vectors, which give a number when applied to column vectors. We denote this by V ∗ := Hom ( V , K ) {\displaystyle V^{*}:={\text{Hom}}(V,K)} , so that α ∈ V ∗ {\displaystyle \alpha \in V^{*}} is a linear map α : V → K ...

  7. Pivot table - Wikipedia

    en.wikipedia.org/wiki/Pivot_table

    Row labels are used to apply a filter to one or more rows that have to be shown in the pivot table. For instance, if the "Salesperson" field is dragged on this area then the other output table constructed will have values from the column "Salesperson", i.e., one will have a number of rows equal to the number of "Sales Person". There will also ...

  8. DuckDB - Wikipedia

    en.wikipedia.org/wiki/DuckDB

    DuckDB is an open-source column-oriented relational database management system (RDBMS). [1] It is designed to provide high performance on complex queries against large databases in embedded configuration, [2] such as combining tables with hundreds of columns and billions of rows.

  9. k-means clustering - Wikipedia

    en.wikipedia.org/wiki/K-means_clustering

    Davies–Bouldin index: The Davies-Bouldin index is a measure of the how much separation there is between clusters. [32] Lower values of the Davies-Bouldin index indicate a model with better separation. Calinski-Harabasz index: This Index evaluates clusters based on their compactness and separation. The index is calculated using the ratio of ...