diff --git a/src/field/fft.rs b/src/field/fft.rs
index 281ee9d2..1061e7a7 100644
--- a/src/field/fft.rs
+++ b/src/field/fft.rs
@@ -122,10 +122,13 @@ pub fn fft_with_precomputation_power_of_2<F: Field>(
 }
 
 pub fn coset_fft<F: Field>(coefficients: Vec<F>, shift: F) -> Vec<F> {
-    fft(coefficients)
-        .into_iter()
-        .map(|x| x * shift)
-        .collect()
+    let mut points = fft(coefficients);
+    let mut shift_exp_i = F::ONE;
+    for p in points.iter_mut() {
+        *p *= shift_exp_i;
+        shift_exp_i *= shift;
+    }
+    points
 }
 
 pub fn ifft<F: Field>(points: Vec<F>) -> Vec<F> {
@@ -135,10 +138,13 @@ pub fn ifft<F: Field>(points: Vec<F>) -> Vec<F> {
 
 pub fn coset_ifft<F: Field>(points: Vec<F>, shift: F) -> Vec<F> {
     let shift_inv = shift.inverse();
-    ifft(points)
-        .into_iter()
-        .map(|x| x * shift_inv)
-        .collect()
+    let mut shift_inv_exp_i = F::ONE;
+    let mut coeffs = ifft(points);
+    for c in coeffs.iter_mut() {
+        *c *= shift_inv_exp_i;
+        shift_inv_exp_i *= shift_inv;
+    }
+    coeffs
 }
 
 pub fn lde_multiple<F: Field>(points: Vec<Vec<F>>, rate_bits: usize) -> Vec<Vec<F>> {
diff --git a/src/prover.rs b/src/prover.rs
index c9c45929..49a76efb 100644
--- a/src/prover.rs
+++ b/src/prover.rs
@@ -61,6 +61,10 @@ pub(crate) fn prove<F: Field>(
         common_data, prover_data, wire_ldes_t, plonk_z_ldes_t, alpha);
     info!("Computing vanishing poly took {}s", start_vanishing_poly.elapsed().as_secs_f32());
 
+    let div_z_h_start = Instant::now();
+    // TODO
+    info!("Division by Z_H took {}s", div_z_h_start.elapsed().as_secs_f32());
+
     let plonk_t: Vec<F> = todo!(); // vanishing_poly / Z_H
     // Need to convert to coeff form and back?
     let plonk_t_parts = todo!();