# simd_half4 A vector of four 16-bit floating-point elements. ``` typealias simd_half4 = SIMD4 ``` ## Topics ### Functions to create four-element vectors from other vectors [`simd_make_half4(_:)`](/documentation/simd/simd_make_half4(_:)-fx5r) Returns a new vector from the specified two-element vector, and other elements set to zero. [`simd_make_half4(_:)`](/documentation/simd/simd_make_half4(_:)-iuj0) Returns a new vector from the specified three-element vector, and other elements set to zero. [`simd_make_half4(_:)`](/documentation/simd/simd_make_half4(_:)-9u2ra) Returns a new vector from the specified vector. [`simd_make_half4(_:)`](/documentation/simd/simd_make_half4(_:)-10t2p) Returns a new vector by truncating the specified eight-element vector. [`simd_make_half4(_:)`](/documentation/simd/simd_make_half4(_:)-43737) Returns a new vector by truncating the specified 16-element vector. [`simd_make_half4(_:)`](/documentation/simd/simd_make_half4(_:)-60ltf) Returns a new vector by truncating the specified 32-element vector. [`simd_make_half4(_:_:)`](/documentation/simd/simd_make_half4(_:_:)-2ea2z) Returns a new vector from the specified vectors. [`simd_make_half4_undef(_:)`](/documentation/simd/simd_make_half4_undef(_:)-16ipv) Returns a new vector from the specified two-element vector, and other elements undefined. [`simd_make_half4_undef(_:)`](/documentation/simd/simd_make_half4_undef(_:)-136jo) Returns a new vector from the specified three-element vector, and other elements undefined. ### Functions to create four-element vectors from scalar values [`simd_make_half4(_:)`](/documentation/simd/simd_make_half4(_:)-6lkh9) Returns a new vector with the first element set to a scalar value, and other elements set to zero. [`simd_make_half4(_:_:_:_:)`](/documentation/simd/simd_make_half4(_:_:_:_:)) Returns a new vector from the specified scalar values. [`simd_make_half4_undef(_:)`](/documentation/simd/simd_make_half4_undef(_:)-4axzi) Returns a new vector with the first element set to a scalar value, and other elements undefined. [`simd_make_half4(_:_:)`](/documentation/simd/simd_make_half4(_:_:)-2n13g) Returns a new vector from a scalar value and a vector. [`simd_make_half4(_:_:)`](/documentation/simd/simd_make_half4(_:_:)-6uygn) Returns a new vector from a vector and a scalar value. [`simd_make_half4(_:_:_:)`](/documentation/simd/simd_make_half4(_:_:_:)-43wuv) Returns a new vector from a scalar value, a vector, and a scalar value. [`simd_make_half4(_:_:_:)`](/documentation/simd/simd_make_half4(_:_:_:)-74ybg) Returns a new vector from two scalar values and a vector. [`simd_make_half4(_:_:_:)`](/documentation/simd/simd_make_half4(_:_:_:)-6g0kb) Returns a new vector from a vector and scalar values. ### Functions to create four-element vectors from vectors of other types [`simd_half`](/documentation/simd/simd_half-3g8pd) Returns a new vector from the specified vector of 8-bit, signed-integer elements. [`simd_half`](/documentation/simd/simd_half-3fyxd) Returns a new vector from the specified vector of 8-bit, unsigned-integer elements. [`simd_half`](/documentation/simd/simd_half-3g3td) Returns a new vector from the specified vector of 16-bit, signed-integer elements. [`simd_half`](/documentation/simd/simd_half-3fu1d) Returns a new vector from the specified vector of 16-bit, unsigned-integer elements. [`simd_half`](/documentation/simd/simd_half-3gau9) Returns a new vector from the specified vector of 32-bit, signed-integer elements. [`simd_half`](/documentation/simd/simd_half-3g0m9) Returns a new vector from the specified vector of 32-bit, unsigned-integer elements. [`simd_half`](/documentation/simd/simd_half-3g9t7) Returns a new vector from the specified vector of 64-bit, signed-integer elements. [`simd_half`](/documentation/simd/simd_half-3fzzf) Returns a new vector from the specified vector of 64-bit, unsigned-integer elements. [`simd_half`](/documentation/simd/simd_half-3g13n) Returns a new vector from the specified vector of 16-bit, floating-point elements. [`simd_half`](/documentation/simd/simd_half-3fxvr) Returns a new vector from the specified vector of 32-bit, floating-point elements. [`simd_half`](/documentation/simd/simd_half-3fxbf) Returns a new vector from the specified vector of 64-bit, floating-point elements. ### Common functions [`simd_abs(_:)`](/documentation/simd/simd_abs(_:)-81q3k) Returns the absolute value of each element in a vector. [`simd_clamp(_:_:_:)`](/documentation/simd/simd_clamp(_:_:_:)-2vvpa) Returns each element in a vector clamped to a specified range. [`simd_equal(_:_:)`](/documentation/simd/simd_equal(_:_:)-6nuuw) Returns true if every element in a vector is exactly equal to the corresponding element in a second vector, and otherwise returns false. [`simd_fract(_:)`](/documentation/simd/simd_fract(_:)-3w251) Returns the fractional part of each element in a vector. [`simd_sign(_:)`](/documentation/simd/simd_sign(_:)-7533b) Returns the sign of each element in a vector. [`simd_step(_:_:)`](/documentation/simd/simd_step(_:_:)-4knqw) Returns zero for each element in a vector less than a specified edge, and otherwise returns one. ### Reduce functions [`simd_reduce_add(_:)`](/documentation/simd/simd_reduce_add(_:)-2ylck) Returns the sum of all elements in a vector. [`simd_reduce_max(_:)`](/documentation/simd/simd_reduce_max(_:)-4qtu6) Returns the maximum value in a vector. [`simd_reduce_min(_:)`](/documentation/simd/simd_reduce_min(_:)-4ulc6) Returns the minimum value in a vector. ### Interpolation functions [`simd_mix(_:_:_:)`](/documentation/simd/simd_mix(_:_:_:)-4uou1) Returns an element-wise linearly interpolated value between two vectors. [`simd_smoothstep(_:_:_:)`](/documentation/simd/simd_smoothstep(_:_:_:)-7gsfq) Returns an element-wise smoothly interpolated value between two vectors. ### Extrema functions [`simd_max(_:_:)`](/documentation/simd/simd_max(_:_:)-64l5l) Returns the maximum value of each element in a vector. [`simd_min(_:_:)`](/documentation/simd/simd_min(_:_:)-1ep1a) Returns the minimum value of each element in a vector. ### Reciprocal and reciprocal square root functions [`simd_recip(_:)`](/documentation/simd/simd_recip(_:)-822hi) Returns the reciprocal of each element in a vector. [`simd_rsqrt(_:)`](/documentation/simd/simd_rsqrt(_:)-i99u) Returns the reciprocal square root of each element in a vector. [`simd_precise_recip(_:)`](/documentation/simd/simd_precise_recip(_:)-6pwwe) Returns the precise reciprocal of each element in a vector. [`simd_precise_rsqrt(_:)`](/documentation/simd/simd_precise_rsqrt(_:)-13530) Returns the precise reciprocal square root of each element in a vector. [`simd_fast_recip(_:)`](/documentation/simd/simd_fast_recip(_:)-7d3) Returns the fast reciprocal of each element in a vector. [`simd_fast_rsqrt(_:)`](/documentation/simd/simd_fast_rsqrt(_:)-8pakw) Returns the fast reciprocal square root of each element in a vector. ### Geometry functions [`simd_dot`](/documentation/simd/simd_dot-87ssc) Returns the dot product of two vectors. [`simd_normalize`](/documentation/simd/simd_normalize-9o6iq) Returns a vector pointing in the same direction of the supplied vector, with a length of 1. [`simd_fast_normalize`](/documentation/simd/simd_fast_normalize-3vaz) Returns the fast normalized vector. [`simd_precise_normalize`](/documentation/simd/simd_precise_normalize-4vqaw) Returns the precise normalized vector. [`simd_project`](/documentation/simd/simd_project-24ld6) Returns the first vector projected onto the second vector. [`simd_precise_project`](/documentation/simd/simd_precise_project-1cw2i) Returns the precise projected vector. [`simd_fast_project`](/documentation/simd/simd_fast_project-6ymj6) Returns the fast projected vector. [`simd_reflect`](/documentation/simd/simd_reflect-9r760) Returns the reflection direction of an incident vector and a unit normal vector. [`simd_refract`](/documentation/simd/simd_refract-6q75f) Returns the refraction direction of an incident vector, a unit normal vector, and an index of refraction eta. ### Vector norm functions [`simd_norm_one`](/documentation/simd/simd_norm_one-sdw3) Returns the sum of the absolute values of a vector. [`simd_norm_inf`](/documentation/simd/simd_norm_inf-97p52) Returns the maximum absolute value of a vector. ### Length and distance functions [`simd_length`](/documentation/simd/simd_length-3fmwz) Returns the length of a vector. [`simd_fast_length`](/documentation/simd/simd_fast_length-4om0k) Returns the fast length of a vector. [`simd_precise_length`](/documentation/simd/simd_precise_length-7dx4e) Returns the precise length of a vector. [`simd_length_squared`](/documentation/simd/simd_length_squared-2t92l) Returns the square of the length of a vector. [`simd_distance`](/documentation/simd/simd_distance-9tmum) Returns the distance between two vectors. [`simd_fast_distance`](/documentation/simd/simd_fast_distance-7jdgd) Returns the fast distance between two vectors. [`simd_precise_distance`](/documentation/simd/simd_precise_distance-3g45n) Returns the precise distance between two vectors. [`simd_distance_squared`](/documentation/simd/simd_distance_squared-1uyo7) Returns the square of the distance between two vectors. ### Logic functions [`simd_select(_:_:_:)`](/documentation/simd/simd_select(_:_:_:)-4vjt) Returns a vector that contains elements from either the first or second parameter, based on the corresponding element’s high-order bit in the mask. [`simd_bitselect(_:_:_:)`](/documentation/simd/simd_bitselect(_:_:_:)-6gy8u) Returns a vector that contains elements from either the first or second parameter, based on the corresponding element in the third parameter. ### Math functions [`simd_muladd(_:_:_:)`](/documentation/simd/simd_muladd(_:_:_:)-99g6r) Returns the multiply-add result for corresponding elements in three vectors. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)