From 8118427e1dc16998b225f375cf160697ef2f3bd9 Mon Sep 17 00:00:00 2001
From: Edward Middleton <edward.middleton@vortorus.net>
Date: Wed, 25 Feb 2026 02:15:41 +0900
Subject: [PATCH] Add optional half crate support for ScalarOperand

Add `half` feature flag with optional dependency on the `half` crate.
When enabled, implements `ScalarOperand` for `half::f16` and `half::bf16`,
allowing these types to participate in array arithmetic operations.

This enables the burn-ndarray backend to support bf16/f16 tensor operations.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 Cargo.lock      | 26 ++++++++++++++++++++++----
 Cargo.toml      |  2 ++
 src/impl_ops.rs |  5 +++++
 3 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 3cc64a637..54dfd9002 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -205,6 +205,12 @@ version = "0.8.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d0a5c400df2834b80a4c3327b3aad3a4c4cd4de0629063962b03235697506a28"
 
+[[package]]
+name = "crunchy"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "460fbee9c2c2f33933d720630a6a0bac33ba7053db5344fac858d4b8952d77d5"
+
 [[package]]
 name = "defmac"
 version = "0.2.1"
@@ -323,6 +329,17 @@ dependencies = [
  "wasi 0.14.2+wasi-0.2.4",
 ]
 
+[[package]]
+name = "half"
+version = "2.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6ea2d84b969582b4b1864a92dc5d27cd2b77b622a8d79306834f1be5ba20d84b"
+dependencies = [
+ "cfg-if",
+ "crunchy",
+ "zerocopy",
+]
+
 [[package]]
 name = "hermit-abi"
 version = "0.3.9"
@@ -462,6 +479,7 @@ dependencies = [
  "approx",
  "cblas-sys",
  "defmac",
+ "half",
  "itertools",
  "libc",
  "matrixmultiply",
@@ -1342,18 +1360,18 @@ dependencies = [
 
 [[package]]
 name = "zerocopy"
-version = "0.8.25"
+version = "0.8.39"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a1702d9583232ddb9174e01bb7c15a2ab8fb1bc6f227aa1233858c351a3ba0cb"
+checksum = "db6d35d663eadb6c932438e763b262fe1a70987f9ae936e60158176d710cae4a"
 dependencies = [
  "zerocopy-derive",
 ]
 
 [[package]]
 name = "zerocopy-derive"
-version = "0.8.25"
+version = "0.8.39"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "28a6e20d751156648aa063f3800b706ee209a32c0b4d9f24be3d980b01be55ef"
+checksum = "4122cd3169e94605190e77839c9a40d40ed048d305bfdc146e7df40ab0f3e517"
 dependencies = [
  "proc-macro2",
  "quote",
diff --git a/Cargo.toml b/Cargo.toml
index bee7dcad1..046493270 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -48,6 +48,7 @@ libc = { version = "0.2.82", optional = true }
 
 matrixmultiply = { version = "0.3.2", default-features = false, features=["cgemm"] }
 
+half = { version = "2", optional = true, default-features = false }
 serde = { version = "1.0", optional = true, default-features = false, features = ["alloc"] }
 rawpointer = { version = "0.2" }
 
@@ -65,6 +66,7 @@ default = ["std"]
 # See README for more instructions
 blas = ["dep:cblas-sys", "dep:libc"]
 
+half = ["dep:half"]
 serde = ["dep:serde"]
 
 std = ["num-traits/std", "matrixmultiply/std"]
diff --git a/src/impl_ops.rs b/src/impl_ops.rs
index 53f49cc43..d0b089e52 100644
--- a/src/impl_ops.rs
+++ b/src/impl_ops.rs
@@ -50,6 +50,11 @@ impl ScalarOperand for f64 {}
 impl ScalarOperand for Complex<f32> {}
 impl ScalarOperand for Complex<f64> {}
 
+#[cfg(feature = "half")]
+impl ScalarOperand for half::f16 {}
+#[cfg(feature = "half")]
+impl ScalarOperand for half::bf16 {}
+
 macro_rules! impl_binary_op(
     ($trt:ident, $operator:tt, $mth:ident, $iop:tt, $doc:expr) => (
 /// Perform elementwise