diff --git a/crates/eko/src/lib.rs b/crates/eko/src/lib.rs
index 9f99a7e30..4e6347494 100644
--- a/crates/eko/src/lib.rs
+++ b/crates/eko/src/lib.rs
@@ -96,8 +96,8 @@ pub unsafe extern "C" fn rust_quad_ker_qcd(u: f64, rargs: *mut c_void) -> f64 {
     (args.py)(
         raw.re.as_ptr(),
         raw.im.as_ptr(),
-        c.n.re,
-        c.n.im,
+        c.n().re,
+        c.n().im,
         jac.re,
         jac.im,
         args.order_qcd,
diff --git a/crates/ekore/src/anomalous_dimensions/unpolarized/spacelike/as1.rs b/crates/ekore/src/anomalous_dimensions/unpolarized/spacelike/as1.rs
index 7882227d3..5b5fc6ee6 100644
--- a/crates/ekore/src/anomalous_dimensions/unpolarized/spacelike/as1.rs
+++ b/crates/ekore/src/anomalous_dimensions/unpolarized/spacelike/as1.rs
@@ -9,7 +9,7 @@ use crate::harmonics::cache::{Cache, K};
 ///
 /// Implements Eq. (3.4) of [\[Moch:2004pa\]][crate::bib::Moch2004pa].
 pub fn gamma_ns(c: &mut Cache, _nf: u8) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let S1 = c.get(K::S1);
     let gamma = -(3.0 - 4.0 * S1 + 2.0 / N / (N + 1.0));
     CF * gamma
@@ -19,7 +19,7 @@ pub fn gamma_ns(c: &mut Cache, _nf: u8) -> Complex<f64> {
 ///
 /// Implements Eq. (3.5) of [\[Vogt:2004mw\]](crate::bib::Vogt2004mw).
 pub fn gamma_qg(c: &mut Cache, nf: u8) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let gamma = -(N.powu(2) + N + 2.0) / (N * (N + 1.0) * (N + 2.0));
     2.0 * TR * 2.0 * (nf as f64) * gamma
 }
@@ -28,7 +28,7 @@ pub fn gamma_qg(c: &mut Cache, nf: u8) -> Complex<f64> {
 ///
 /// Implements Eq. (3.5) of [\[Vogt:2004mw\]](crate::bib::Vogt2004mw).
 pub fn gamma_gq(c: &mut Cache, _nf: u8) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let gamma = -(N.powu(2) + N + 2.0) / (N * (N + 1.0) * (N - 1.0));
     2.0 * CF * gamma
 }
@@ -37,7 +37,7 @@ pub fn gamma_gq(c: &mut Cache, _nf: u8) -> Complex<f64> {
 ///
 /// Implements Eq. (3.5) of [\[Vogt:2004mw\]](crate::bib::Vogt2004mw).
 pub fn gamma_gg(c: &mut Cache, nf: u8) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let S1 = c.get(K::S1);
     let gamma = S1 - 1.0 / N / (N - 1.0) - 1.0 / (N + 1.0) / (N + 2.0);
     CA * (4.0 * gamma - 11.0 / 3.0) + 4.0 / 3.0 * TR * (nf as f64)
diff --git a/crates/ekore/src/anomalous_dimensions/unpolarized/spacelike/as2.rs b/crates/ekore/src/anomalous_dimensions/unpolarized/spacelike/as2.rs
index 195f69fec..857034ab8 100644
--- a/crates/ekore/src/anomalous_dimensions/unpolarized/spacelike/as2.rs
+++ b/crates/ekore/src/anomalous_dimensions/unpolarized/spacelike/as2.rs
@@ -10,7 +10,7 @@ use crate::harmonics::cache::{Cache, K};
 ///
 /// Implements Eq. (3.6) of [\[Moch:2004pa\]][crate::bib::Moch2004pa].
 pub fn gamma_nsm(c: &mut Cache, nf: u8) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let S1 = c.get(K::S1);
     let S2 = c.get(K::S2);
     let Sp1m = c.get(K::S1mh);
@@ -50,7 +50,7 @@ pub fn gamma_nsm(c: &mut Cache, nf: u8) -> Complex<f64> {
 ///
 /// Implements Eq. (3.5) of [\[Moch:2004pa\]][crate::bib::Moch2004pa].
 pub fn gamma_nsp(c: &mut Cache, nf: u8) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let S1 = c.get(K::S1);
     let S2 = c.get(K::S2);
     let Sp1p = c.get(K::S1h);
@@ -90,7 +90,7 @@ pub fn gamma_nsp(c: &mut Cache, nf: u8) -> Complex<f64> {
 ///
 /// Implements Eq. (3.6) of [\[Vogt:2004mw\]][crate::bib::Vogt2004mw].
 pub fn gamma_ps(c: &mut Cache, nf: u8) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let gqqps1_nfcf = (-4. * (2. + N * (5. + N)) * (4. + N * (4. + N * (7. + 5. * N))))
         / ((-1. + N) * N.powu(3) * (1. + N).powu(3) * (2. + N).powu(2));
     2.0 * TR * (nf as f64) * CF * gqqps1_nfcf
@@ -100,7 +100,7 @@ pub fn gamma_ps(c: &mut Cache, nf: u8) -> Complex<f64> {
 ///
 /// Implements Eq. (3.7) of [\[Vogt:2004mw\]][crate::bib::Vogt2004mw].
 pub fn gamma_qg(c: &mut Cache, nf: u8) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let S1 = c.get(K::S1);
     let S2 = c.get(K::S2);
     let Sp2p = c.get(K::S2h);
@@ -128,7 +128,7 @@ pub fn gamma_qg(c: &mut Cache, nf: u8) -> Complex<f64> {
 ///
 /// Implements Eq. (3.8) of [\[Vogt:2004mw\]][crate::bib::Vogt2004mw].
 pub fn gamma_gq(c: &mut Cache, nf: u8) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let S1 = c.get(K::S1);
     let S2 = c.get(K::S2);
     let Sp2p = c.get(K::S2h);
@@ -164,7 +164,7 @@ pub fn gamma_gq(c: &mut Cache, nf: u8) -> Complex<f64> {
 ///
 /// Implements Eq. (3.9) of [\[Vogt:2004mw\]][crate::bib::Vogt2004mw].
 pub fn gamma_gg(c: &mut Cache, nf: u8) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let S1 = c.get(K::S1);
     let Sp1p = c.get(K::S1h);
     let Sp2p = c.get(K::S2h);
diff --git a/crates/ekore/src/anomalous_dimensions/unpolarized/spacelike/as3.rs b/crates/ekore/src/anomalous_dimensions/unpolarized/spacelike/as3.rs
index e9506b2ea..d491db0e9 100644
--- a/crates/ekore/src/anomalous_dimensions/unpolarized/spacelike/as3.rs
+++ b/crates/ekore/src/anomalous_dimensions/unpolarized/spacelike/as3.rs
@@ -11,7 +11,7 @@ use crate::harmonics::cache::{Cache, K};
 ///
 /// Implements Eq. (3.8) of [\[Moch:2004pa\]][crate::bib::Moch2004pa].
 pub fn gamma_nsm(c: &mut Cache, nf: u8) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let S1 = c.get(K::S1);
     let S2 = c.get(K::S2);
     let S3 = c.get(K::S3);
@@ -68,7 +68,7 @@ pub fn gamma_nsm(c: &mut Cache, nf: u8) -> Complex<f64> {
 ///
 /// Implements Eq. (3.7) of [\[Moch:2004pa\]][crate::bib::Moch2004pa].
 pub fn gamma_nsp(c: &mut Cache, nf: u8) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let S1 = c.get(K::S1);
     let S2 = c.get(K::S2);
     let S3 = c.get(K::S3);
@@ -125,7 +125,7 @@ pub fn gamma_nsp(c: &mut Cache, nf: u8) -> Complex<f64> {
 ///
 /// Implements Eq. (3.9) of [\[Moch:2004pa\]][crate::bib::Moch2004pa].
 pub fn gamma_nsv(c: &mut Cache, nf: u8) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let S1 = c.get(K::S1);
     let S2 = c.get(K::S2);
     let S3 = c.get(K::S3);
@@ -162,7 +162,7 @@ pub fn gamma_nsv(c: &mut Cache, nf: u8) -> Complex<f64> {
 ///
 /// Implements Eq. (3.10) of [\[Vogt:2004mw\]][crate::bib::Vogt2004mw].
 pub fn gamma_ps(c: &mut Cache, nf: u8) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let S1 = c.get(K::S1);
     let S2 = c.get(K::S2);
     let S3 = c.get(K::S3);
@@ -218,7 +218,7 @@ pub fn gamma_ps(c: &mut Cache, nf: u8) -> Complex<f64> {
 ///
 /// Implements Eq. (3.11) of [\[Vogt:2004mw\]][crate::bib::Vogt2004mw].
 pub fn gamma_qg(c: &mut Cache, nf: u8) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let S1 = c.get(K::S1);
     let S2 = c.get(K::S2);
     let S3 = c.get(K::S3);
@@ -275,7 +275,7 @@ pub fn gamma_qg(c: &mut Cache, nf: u8) -> Complex<f64> {
 ///
 /// Implements Eq. (3.12) of [\[Vogt:2004mw\]][crate::bib::Vogt2004mw].
 pub fn gamma_gq(c: &mut Cache, nf: u8) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let S1 = c.get(K::S1);
     let S2 = c.get(K::S2);
     let S3 = c.get(K::S3);
@@ -348,7 +348,7 @@ pub fn gamma_gq(c: &mut Cache, nf: u8) -> Complex<f64> {
 ///
 /// Implements Eq. (3.13) of [\[Vogt:2004mw\]][crate::bib::Vogt2004mw].
 pub fn gamma_gg(c: &mut Cache, nf: u8) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let S1 = c.get(K::S1);
     let S2 = c.get(K::S2);
     let S3 = c.get(K::S3);
diff --git a/crates/ekore/src/harmonics/cache.rs b/crates/ekore/src/harmonics/cache.rs
index eb2a9090b..d8f66b595 100644
--- a/crates/ekore/src/harmonics/cache.rs
+++ b/crates/ekore/src/harmonics/cache.rs
@@ -35,7 +35,7 @@ pub enum K {
 /// Hold all cached values.
 pub struct Cache {
     /// Mellin N
-    pub n: Complex<f64>,
+    n: Complex<f64>,
     /// Mapping
     m: HashMap<K, Complex<f64>>,
 }
@@ -49,6 +49,11 @@ impl Cache {
         }
     }
 
+    /// Get Mellin N.
+    pub fn n(&self) -> Complex<f64> {
+        Complex::new(self.n.re, self.n.im)
+    }
+
     /// Retrieve an element.
     pub fn get(&mut self, k: K) -> Complex<f64> {
         let val = self.m.get(&k);
@@ -94,11 +99,21 @@ pub fn recursive_harmonic_sum(
 
 #[cfg(test)]
 mod tests {
-    use crate::harmonics::cache::recursive_harmonic_sum;
+    use super::*;
     use crate::harmonics::{w1, w2, w3, w4};
     use crate::{assert_approx_eq_cmplx, cmplx};
     use num::complex::Complex;
 
+    #[test]
+    fn n() {
+        let n = cmplx!(1., 0.);
+        let c = Cache::new(n);
+        let mut m = c.n();
+        m += cmplx!(1., 0.);
+        assert_approx_eq_cmplx!(f64, c.n(), n);
+        assert_approx_eq_cmplx!(f64, m, cmplx!(2., 0.));
+    }
+
     #[test]
     fn test_recursive_harmonic_sum() {
         const SX: [fn(Complex<f64>) -> Complex<f64>; 4] = [w1::S1, w2::S2, w3::S3, w4::S4];
diff --git a/crates/ekore/src/operator_matrix_elements/unpolarized/spacelike/as1.rs b/crates/ekore/src/operator_matrix_elements/unpolarized/spacelike/as1.rs
index 0e5145d61..c2409d2d9 100644
--- a/crates/ekore/src/operator_matrix_elements/unpolarized/spacelike/as1.rs
+++ b/crates/ekore/src/operator_matrix_elements/unpolarized/spacelike/as1.rs
@@ -11,7 +11,7 @@ use crate::harmonics::cache::{Cache, K};
 ///
 /// Implements Eq. (20a) of [\[Ball:2015tna\]](crate::bib::Ball2015tna).
 pub fn A_hh(c: &mut Cache, _nf: u8, L: f64) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let S1m = c.get(K::S1) - 1. / N;
     let S2m = c.get(K::S2) - 1. / N.powu(2);
     let ahh_l = (2. + N - 3. * N.powu(2)) / (N * (1. + N)) + 4. * S1m;
@@ -30,7 +30,7 @@ pub fn A_hh(c: &mut Cache, _nf: u8, L: f64) -> Complex<f64> {
 ///
 /// Implements Eq. (20b) of [\[Ball:2015tna\]](crate::bib::Ball2015tna).
 pub fn A_gh(c: &mut Cache, _nf: u8, L: f64) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let agh_l1 = (2. + N + N.powu(2)) / (N * (N.powu(2) - 1.));
     let agh_l0 = (-4. + 2. * N + N.powu(2) * (15. + N * (3. + N - N.powu(2))))
         / (N * (N.powu(2) - 1.)).powu(2);
@@ -41,7 +41,7 @@ pub fn A_gh(c: &mut Cache, _nf: u8, L: f64) -> Complex<f64> {
 ///
 /// Implements Eq. (B.2) of [\[Buza:1996wv\]](crate::bib::Buza1996wv).
 pub fn A_hg(c: &mut Cache, _nf: u8, L: f64) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let den = 1. / (N * (N + 1.) * (2. + N));
     let num = 2. * (2. + N + N.powu(2));
     num * den * L
diff --git a/crates/ekore/src/operator_matrix_elements/unpolarized/spacelike/as2.rs b/crates/ekore/src/operator_matrix_elements/unpolarized/spacelike/as2.rs
index 0e176c282..7fee55609 100644
--- a/crates/ekore/src/operator_matrix_elements/unpolarized/spacelike/as2.rs
+++ b/crates/ekore/src/operator_matrix_elements/unpolarized/spacelike/as2.rs
@@ -13,7 +13,7 @@ use crate::operator_matrix_elements::unpolarized::spacelike::as1;
 /// |NNLO| light-light non-singlet |OME|.
 /// It is given in Eq.() of
 pub fn A_qq_ns(c: &mut Cache, _nf: u8, L: f64) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let S1 = c.get(K::S1);
     let S2 = c.get(K::S2);
     let S3 = c.get(K::S3);
@@ -44,7 +44,7 @@ pub fn A_qq_ns(c: &mut Cache, _nf: u8, L: f64) -> Complex<f64> {
 /// |NNLO| heavy-light pure-singlet |OME|
 /// It is given in Eq.() of
 pub fn A_hq_ps(c: &mut Cache, _nf: u8, L: f64) -> Complex<f64> {
-    let N = c.n;
+    let N = c.n();
     let S2 = c.get(K::S1);
     let F1M = 1.0 / (N - 1.0) * (ZETA2 - (S2 - 1.0 / N.powu(2)));
     let F11 = 1.0 / (N + 1.0) * (ZETA2 - (S2 + 1.0 / (N + 1.0).powu(2)));
diff --git a/crates/ekore/src/util.rs b/crates/ekore/src/util.rs
index 8d98f25b0..0d815bc98 100644
--- a/crates/ekore/src/util.rs
+++ b/crates/ekore/src/util.rs
@@ -13,18 +13,15 @@ macro_rules! cmplx {
 #[macro_export]
 macro_rules! assert_approx_eq_cmplx {
     ($size:ty, $ref:expr, $target:expr) => {
-        use float_cmp::assert_approx_eq;
-        assert_approx_eq!($size, $ref.re, $target.re);
-        assert_approx_eq!($size, $ref.im, $target.im);
+        float_cmp::assert_approx_eq!($size, $ref.re, $target.re);
+        float_cmp::assert_approx_eq!($size, $ref.im, $target.im);
     };
     ($size:ty, $ref:expr, $target:expr, ulps=$ulps:expr) => {
-        use float_cmp::assert_approx_eq;
-        assert_approx_eq!($size, $ref.re, $target.re, ulps = $ulps);
-        assert_approx_eq!($size, $ref.im, $target.im, ulps = $ulps);
+        float_cmp::assert_approx_eq!($size, $ref.re, $target.re, ulps = $ulps);
+        float_cmp::assert_approx_eq!($size, $ref.im, $target.im, ulps = $ulps);
     };
     ($size:ty, $ref:expr, $target:expr, epsilon=$epsilon:expr) => {
-        use float_cmp::assert_approx_eq;
-        assert_approx_eq!($size, $ref.re, $target.re, epsilon = $epsilon);
-        assert_approx_eq!($size, $ref.im, $target.im, epsilon = $epsilon);
+        float_cmp::assert_approx_eq!($size, $ref.re, $target.re, epsilon = $epsilon);
+        float_cmp::assert_approx_eq!($size, $ref.im, $target.im, epsilon = $epsilon);
     };
 }