Rollback proving function

sumcheck/src/gpu/sumcheck.rs

@@ -22,7 +22,6 @@ impl<F: PrimeField + FromFieldBinding<F> + ToFieldBinding<F>> GPUApiWrapper<F> {
         challenge: &mut CudaSlice<FieldBinding>,
         round_evals: RefCell<CudaViewMut<FieldBinding>>,
         transcript: &mut Keccak256Transcript<F>,
-        challenges: &mut Vec<F>,
     ) -> Result<(), LibraryError> {
         let initial_poly_num_vars = num_vars;
         for round in 0..num_vars {
@@ -39,7 +38,6 @@ impl<F: PrimeField + FromFieldBinding<F> + ToFieldBinding<F>> GPUApiWrapper<F> {
             )?;
             // squeeze challenge
             let alpha = transcript.squeeze_challenge();
-            challenges.push(alpha);
             let c = vec![alpha];
             self.overwrite_to_device(c.as_slice(), challenge)
                 .map_err(|e| LibraryError::Driver(e))?;
@@ -458,7 +456,6 @@ mod tests {
         println!("Time taken to copy data to device : {:.2?}", now.elapsed());
 
         let now = Instant::now();
-        let mut unused_c = vec![];
         gpu_api_wrapper.prove_sumcheck(
             num_vars,
             num_polys,
@@ -473,7 +470,6 @@ mod tests {
             &mut challenges,
             round_evals_view,
             &mut transcript,
-            &mut unused_c,
         )?;
         gpu_api_wrapper
             .gpu