zig

commit e6be6d97683d5443f48ce8b6d86fdf27f0f1d556 (tree)
parent 527055a8215b23a13fb407bdeba2908b8206f6f0
Author: Veikka Tuominen <git@vexu.eu>
Date:   Tue, 30 Aug 2022 13:02:17 +0300

std.rand: make weightedIndex proportions param a const slice

The function does not mutate the proportions and the signature should reflect that.

Diffstat:
M
lib/std/rand.zig
 | 
2
+-
M
lib/std/rand/test.zig
 | 
2
+-

2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/lib/std/rand.zig b/lib/std/rand.zig
@@ -343,7 +343,7 @@ pub const Random = struct {
     ///
     /// This is useful for selecting an item from a slice where weights are not equal.
     /// `T` must be a numeric type capable of holding the sum of `proportions`.
-    pub fn weightedIndex(r: std.rand.Random, comptime T: type, proportions: []T) usize {
+    pub fn weightedIndex(r: std.rand.Random, comptime T: type, proportions: []const T) usize {
         // This implementation works by summing the proportions and picking a random
         //  point in [0, sum).  We then loop over the proportions, accumulating
         //  until our accumulator is greater than the random point.
diff --git a/lib/std/rand/test.zig b/lib/std/rand/test.zig
@@ -452,7 +452,7 @@ test "Random weightedIndex" {
         var prng = DefaultPrng.init(0);
         const random = prng.random();
 
-        var proportions = [_]T{ 2, 1, 1, 2 };
+        const proportions = [_]T{ 2, 1, 1, 2 };
         var counts = [_]f64{ 0, 0, 0, 0 };
 
         const n_trials: u64 = 10_000;