start specs

Author: jalvesz

doc/specs/stdlib_intrinsics.md

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+---
+title: intrinsics
+---
+
+# The `stdlib_intrinsics` module
+
+[TOC]
+
+## Introduction
+
+The `stdlib_intrinsics` module provides replacements for some of the well known intrinsic functions found in Fortran compilers for which either a faster and/or more accurate implementation is found which has also proven of interest to the Fortran community.
+
+<!-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -->
+### `fsum` function
+
+#### Description
+
+The `fsum` function can replace the intrinsic `sum` for 1D `real` or `complex` arrays. It follows a chunked implementation which maximaxes vectorization potential as well as reducing the round-off error.
+
+#### Syntax
+
+`res = ` [[stdlib_intrinsics(module):fsum(interface)]] ` (x [,mask] )`
+
+#### Status
+
+Experimental
+
+#### Class
+
+Pure function.
+
+#### Argument(s)
+
+`x`: 1D array of either `real` or `complex` type. This argument is `intent(in)`.
+`mask`: 1D array of `logical` values. This argument is `intent(in)`.
+
+#### Output value or Result value
+
+The output is a scalar of `type` and `kind` same as to that of `x`.
+
+#### Example
+
+```fortran
+{!example/math/example_intrinsics_sum.f90!}
+```