import binomial from num-integer

qiskit-community · Jan 10, 2025 · cd9ce59 · cd9ce59
1 parent 2b9ba3c
commit cd9ce59
Show file tree

Hide file tree

Showing 3 changed files with 3 additions and 8 deletions.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -18,6 +18,7 @@ pyo3 = { version = "0.21", features = [
     "num-complex",
     "abi3-py39",
 ] }
+num-integer = "0.1"
 
 [target.'cfg(target_os = "linux")'.dependencies]
 blas-src = { version = "0.10", features = ["openblas"] }

diff --git a/src/fermion_operator.rs b/src/fermion_operator.rs
@@ -8,6 +8,7 @@
 // copyright notice, and modified files need to carry a notice indicating
 // that they have been altered from the originals.
 
+use num_integer::binomial;
 use numpy::Complex64;
 use pyo3::class::basic::CompareOp;
 use pyo3::exceptions::PyKeyError;
@@ -516,14 +517,6 @@ fn term_trace(op: &[(bool, bool, i32)], norb: usize, nelec: (usize, usize)) -> i
         }
     }
 
-    let binomial = |n, k| {
-        if k > n {
-            0
-        } else {
-            (1..=n).rev().take(k).product::<usize>() / (1..=k).product::<usize>()
-        }
-    };
-
     term_phase(op)
         * binomial(norb - norb_alpha, n_alpha - nelec_alpha) as i32
         * binomial(norb - norb_beta, n_beta - nelec_beta) as i32