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+[simd.creation]
+
+# 29 Numerics library [[numerics]](./#numerics)
+
+## 29.10 Data-parallel types [[simd]](simd#creation)
+
+### 29.10.8 basic_vec non-member operations [[simd.nonmembers]](simd.nonmembers#simd.creation)
+
+#### 29.10.8.11 basic_vec and basic_mask creation [simd.creation]
+
+[ð](#lib:chunk,simd)
+
+`template<class T, class Abi>
+  constexpr auto chunk(const basic_vec<typename T::value_type, Abi>& x) noexcept;
+template<class T, class Abi>
+  constexpr auto chunk(const basic_mask<mask-element-size<T>, Abi>& x) noexcept;
+`
+
+[1](#1)
+
+[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L19123)
+
+*Constraints*: 
+
+- [(1.1)](#1.1)
+
+  For the first overload, T is an enabled specialization of basic_vec[.](#1.1.sentence-1)
+  If basic_vec<typename T::value_type, Abi>::size() % T::size() is not 0, then resize_t<basic_vec<typename T::value_type, Abi>::size()% T::size(), T> is valid and denotes a type[.](#1.1.sentence-2)
+
+- [(1.2)](#1.2)
+
+  For the second overload, T is an enabled specialization of basic_mask[.](#1.2.sentence-1)
+  If basic_mask<*mask-element-size*<T>, Abi>::size() % T::size() is not 0, then resize_t<basic_mask<*mask-element-size*<T>,
+ Abi>::size() % T::size(), T> is valid and denotes a type[.](#1.2.sentence-2)
+
+[2](#2)
+
+[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L19143)
+
+Let N be x.size() / T::size()[.](#2.sentence-1)
+
+[3](#3)
+
+[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L19146)
+
+*Returns*: 
+
+- [(3.1)](#3.1)
+
+  If x.size() % T::size() == 0 is true, an array<T, N> with the ith basic_vec or basic_mask element of the jth array element initialized to the value
+ of the element in x with index i + j * T::size()[.](#3.1.sentence-1)
+
+- [(3.2)](#3.2)
+
+  Otherwise, a tuple of N objects of type T and one object
+ of type resize_t<x.size() % T::size(), T>[.](#3.2.sentence-1)
+  The ith basic_vec or basic_mask element of
+ the jth tuple element of type T is initialized to
+ the value of the element in x with index i + j * T::size()[.](#3.2.sentence-2)
+  The ith basic_vec or basic_mask element of
+ the Nth tuple element is initialized to the value of the
+ element in x with index i + N * T::size()[.](#3.2.sentence-3)
+
+[ð](#lib:chunk,simd_)
+
+`template<simd-size-type N, class T, class Abi>
+  constexpr auto chunk(const basic_vec<T, Abi>& x) noexcept;
+`
+
+[4](#4)
+
+[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L19175)
+
+*Effects*: Equivalent to: return chunk<resize_t<N, basic_vec<T, Abi>>>(x);
+
+[ð](#lib:chunk,simd__)
+
+`template<simd-size-type N, size_t Bytes, class Abi>
+  constexpr auto chunk(const basic_mask<Bytes, Abi>& x) noexcept;
+`
+
+[5](#5)
+
+[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L19187)
+
+*Effects*: Equivalent to: return chunk<resize_t<N, basic_mask<Bytes, Abi>>>(x);
+
+[ð](#lib:cat,simd)
+
+`template<class T, class... Abis>
+  constexpr vec<T, (basic_vec<T, Abis>::size() + ...)>
+    cat(const basic_vec<T, Abis>&... xs) noexcept;
+template<size_t Bytes, class... Abis>
+  constexpr basic_mask<Bytes, deduce-abi-t<integer-from<Bytes>,
+                            (basic_mask<Bytes, Abis>::size() + ...)>>
+    cat(const basic_mask<Bytes, Abis>&... xs) noexcept;
+`
+
+[6](#6)
+
+[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L19204)
+
+*Constraints*: 
+
+- [(6.1)](#6.1)
+
+  For the first overload vec<T, (basic_vec<T, Abis>::size() + ...)> is enabled[.](#6.1.sentence-1)
+
+- [(6.2)](#6.2)
+
+  For the second overload basic_mask<Bytes, *deduce-abi-t*<*integer-from*<Bytes>, (basic_mask<Bytes, Abis>::size() + ...)>> is enabled[.](#6.2.sentence-1)
+
+[7](#7)
+
+[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L19217)
+
+*Returns*: A data-parallel object initialized with the concatenated values in thexs pack of data-parallel objects: The ithbasic_vec/basic_mask element of the jth parameter in the xs pack is copied to the return value's element with
+index i + the sum of the width of the first j parameters in the xs pack[.](#7.sentence-1)