Nixyri/zig
1
0
Fork 0
mirror of https://github.com/ziglang/zig.git synced 2025-02-10 06:30:18 +00:00
Code Issues Packages Projects Releases Wiki Activity

docs: Add @reduce documentation

Browse Source
This commit is contained in:
LemonBoy 2020-11-01 19:51:59 +01:00 committed by Andrew Kelley
parent 0d6a7088dc
commit 577b994507
1 changed files with 43 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
doc/langref.html.in
View File

@ -8209,6 +8209,49 @@ test "vector @splat" {
</p>
{#see_also|Vectors|@shuffle#}
{#header_close#}
{#header_open|@reduce#}
<pre>{#syntax#}@reduce(comptime op: builtin.ReduceOp, value: anytype) std.meta.Child(value){#endsyntax#}</pre>
<p>
Transforms a {#link|vector|Vectors#} into a scalar value by performing a
sequential horizontal reduction of its elements using the specified
specified operator {#syntax#}op{#endsyntax#}.
</p>
<p>
Not every operator is available for every vector element type:
<ul>
<li>{#syntax#}.And{#endsyntax#}, {#syntax#}.Or{#endsyntax#},
{#syntax#}.Xor{#endsyntax#} are available for
{#syntax#}bool{#endsyntax#} vectors,</li>
<li>{#syntax#}.Min{#endsyntax#}, {#syntax#}.Max{#endsyntax#},
{#syntax#}.Add{#endsyntax#}, {#syntax#}.Mul{#endsyntax#} are
available for {#link|floating point|Floats#} vectors,</li>
<li>Every operator is available for {#link|integer|Integers#} vectors.
</ul>
</p>
<p>
Note that {#syntax#}.Add{#endsyntax#} and {#syntax#}.Mul{#endsyntax#}
reductions on integral types are wrapping; when applied on floating point
types the operation associativity is preserved, unless the float mode is
set to {#syntax#}Optimized{#endsyntax#}.
</p>
{#code_begin|test#}
const std = @import("std");
const expect = std.testing.expect;
test "vector @reduce" {
const value: std.meta.Vector(4, i32) = [_]i32{ 1, -1, 1, -1 };
const result = value > @splat(4, @as(i32, 0));
// result is { true, false, true, false };
comptime expect(@TypeOf(result) == std.meta.Vector(4, bool));
const is_all_true = @reduce(.And, result);
comptime expect(@TypeOf(is_all_true) == bool);
expect(is_all_true == false);
}
{#code_end#}
{#see_also|Vectors|@setFloatMode#}
{#header_close#}
{#header_open|@src#}
<pre>{#syntax#}@src() std.builtin.SourceLocation{#endsyntax#}</pre>
<p>