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  2. Spark (mathematics) - Wikipedia

    en.wikipedia.org/wiki/Spark_(mathematics)

    In mathematics, more specifically in linear algebra, the spark of a matrix is the smallest integer such that there exists a set of columns in which are linearly dependent. If all the columns are linearly independent, s p a r k ( A ) {\displaystyle \mathrm {spark} (A)} is usually defined to be 1 more than the number of rows.

  3. Summation by parts - Wikipedia

    en.wikipedia.org/wiki/Summation_by_parts

    It may be used to prove Nicomachus's theorem that the sum of the first cubes equals the square of the sum of the first positive integers. [2] Summation by parts is frequently used to prove Abel's theorem and Dirichlet's test.

  4. Apache Spark - Wikipedia

    en.wikipedia.org/wiki/Apache_Spark

    Spark Core is the foundation of the overall project. It provides distributed task dispatching, scheduling, and basic I/O functionalities, exposed through an application programming interface (for Java, Python, Scala, .NET [16] and R) centered on the RDD abstraction (the Java API is available for other JVM languages, but is also usable for some other non-JVM languages that can connect to the ...

  5. Data orientation - Wikipedia

    en.wikipedia.org/wiki/Data_orientation

    Tabular data is two dimensional — data is modeled as rows and columns. However, computer systems represent data in a linear memory model , both in-disk and in-memory. [ 7 ] [ 8 ] [ 9 ] Therefore, a table in a linear memory model requires mapping its two-dimensional scheme into a one-dimensional space.

  6. Kahan summation algorithm - Wikipedia

    en.wikipedia.org/wiki/Kahan_summation_algorithm

    The algorithm performs summation with two accumulators: sum holds the sum, and c accumulates the parts not assimilated into sum, to nudge the low-order part of sum the next time around. Thus the summation proceeds with "guard digits" in c , which is better than not having any, but is not as good as performing the calculations with double the ...

  7. Direct sum - Wikipedia

    en.wikipedia.org/wiki/Direct_sum

    A similar process can be used to form the direct sum of two vector spaces or two modules. We can also form direct sums with any finite number of summands, for example A ⊕ B ⊕ C {\displaystyle A\oplus B\oplus C} , provided A , B , {\displaystyle A,B,} and C {\displaystyle C} are the same kinds of algebraic structures (e.g., all abelian ...

  8. Sum of normally distributed random variables - Wikipedia

    en.wikipedia.org/wiki/Sum_of_normally...

    This means that the sum of two independent normally distributed random variables is normal, with its mean being the sum of the two means, and its variance being the sum of the two variances (i.e., the square of the standard deviation is the sum of the squares of the standard deviations). [1]

  9. Fermat's theorem on sums of two squares - Wikipedia

    en.wikipedia.org/wiki/Fermat's_theorem_on_sums_of...

    For the avoidance of ambiguity, zero will always be a valid possible constituent of "sums of two squares", so for example every square of an integer is trivially expressible as the sum of two squares by setting one of them to be zero. 1. The product of two numbers, each of which is a sum of two squares, is itself a sum of two squares.