fix: remove clone of coefficients in CPU HAL (risc0#1187)

Came across this todo, and figured I'd just PR in the change to avoid the realloc/copy. > This is safe because the `Ref` guard is kept during the `par_iter` execution. The code can be made to be more verbose to express this, if preferred. --------- Co-authored-by: Frank Laub <[email protected]>
th3nyst1c · Dec 8, 2023 · d625632 · d625632
1 parent 07072d6
commit d625632
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/risc0/zkp/src/hal/cpu.rs b/risc0/zkp/src/hal/cpu.rs
@@ -368,7 +368,7 @@ impl<F: Field> Hal for CpuHal<F> {
         let eval_count = which.size();
         assert_eq!(xs.size(), eval_count);
         assert_eq!(out.size(), eval_count);
-        let coeffs = coeffs.as_slice().to_vec(); // TODO: avoid copy
+        let coeffs = &*coeffs.as_slice();
         let which = which.as_slice();
         let xs = xs.as_slice();
         let mut out = out.as_slice_mut();
@@ -553,7 +553,7 @@ impl<F: Field> Hal for CpuHal<F> {
         let col_size = matrix.size() / output.size();
         assert_eq!(matrix.size(), col_size * row_size);
         let mut output = output.as_slice_mut();
-        let matrix = matrix.as_slice().to_vec(); // TODO: avoid copy
+        let matrix = &*matrix.as_slice();
         let hashfn = self.suite.hashfn.as_ref();
         output.par_iter_mut().enumerate().for_each(|(idx, output)| {
             let column: Vec<Self::Elem> =