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  2. Summed-area table - Wikipedia

    en.wikipedia.org/wiki/Summed-area_table

    A summed-area table is a data structure and algorithm for quickly and efficiently generating the sum of values in a rectangular subset of a grid. In the image processing domain, it is also known as an integral image .

  3. 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 ...

  4. Prefix sum - Wikipedia

    en.wikipedia.org/wiki/Prefix_sum

    Prefix sums are trivial to compute in sequential models of computation, by using the formula y i = y i − 1 + x i to compute each output value in sequence order. However, despite their ease of computation, prefix sums are a useful primitive in certain algorithms such as counting sort, [1] [2] and they form the basis of the scan higher-order function in functional programming languages.

  5. Summation - Wikipedia

    en.wikipedia.org/wiki/Summation

    In mathematics, summation is the addition of a sequence of numbers, called addends or summands; the result is their sum or total.Beside numbers, other types of values can be summed as well: functions, vectors, matrices, polynomials and, in general, elements of any type of mathematical objects on which an operation denoted "+" is defined.

  6. C Sharp syntax - Wikipedia

    en.wikipedia.org/wiki/C_Sharp_syntax

    C# has and allows pointers to selected types (some primitives, enums, strings, pointers, and even arrays and structs if they contain only types that can be pointed [14]) in unsafe context: methods and codeblock marked unsafe. These are syntactically the same as pointers in C and C++.

  7. Abel's summation formula - Wikipedia

    en.wikipedia.org/wiki/Abel's_summation_formula

    Fix a complex number .If = for and () =, then () = ⌊ ⌋ and the formula becomes = ⌊ ⌋ = ⌊ ⌋ + ⌊ ⌋ +. If () >, then the limit as exists and yields the ...

  8. Riemann sum - Wikipedia

    en.wikipedia.org/wiki/Riemann_sum

    Specific choices of give different types of Riemann sums: . If = for all i, the method is the left rule [2] [3] and gives a left Riemann sum.; If = for all i, the method is the right rule [2] [3] and gives a right Riemann sum.

  9. Sum-product number - Wikipedia

    en.wikipedia.org/wiki/Sum-product_number

    The natural numbers 0 and 1 are trivial sum-product numbers for all , and all other sum-product numbers are nontrivial sum-product numbers. For example, the number 144 in base 10 is a sum-product number, because 1 + 4 + 4 = 9 {\displaystyle 1+4+4=9} , 1 × 4 × 4 = 16 {\displaystyle 1\times 4\times 4=16} , and 9 × 16 = 144 {\displaystyle 9 ...