Valarray is something provided in the CeePlusPlus Standard Library

''The C++ standard library provides a class valarray for the processing of arrays of numeric values.''

quoted from TheCppStandardLibrary p.547 where there is also a comment that it may be better to use BlitzPlusPlus.

These are one dimensional templated arrays which can be manipulated as a whole or accessed element by element or sliced.

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CategoryCpp CategoryCppTemplates