From 148a6fc671e4ba17f64ef3ff74e5676c8de2cb8b Mon Sep 17 00:00:00 2001
From: Qiming Sun <osirpt.sun@gmail.com>
Date: Thu, 30 Nov 2023 14:16:56 -0800
Subject: [PATCH] Fix a bug in ci string function

---
 pyscf/lib/mcscf/fci_contract.c | 6 ++----
 pyscf/lib/mcscf/fci_string.c   | 1 +
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/pyscf/lib/mcscf/fci_contract.c b/pyscf/lib/mcscf/fci_contract.c
index fe4af02261..045eb2fed9 100644
--- a/pyscf/lib/mcscf/fci_contract.c
+++ b/pyscf/lib/mcscf/fci_contract.c
@@ -119,9 +119,8 @@ void FCIprog_b_t1(double *ci0, double *t1,
                         sign = EXTRACT_SIGN(tab[j]);
                         if (sign == 0) {
                                 break;
-                        } else {
-                                t1[ia*bcount+str0] += sign * pci[str1];
                         }
+                        t1[ia*bcount+str0] += sign * pci[str1];
                 }
                 tab += nlinkb;
         }
@@ -176,9 +175,8 @@ void FCIspread_b_t1(double *ci1, double *t1,
                         sign = EXTRACT_SIGN(tab[j]);
                         if (sign == 0) {
                                 break;
-                        } else {
-                                pci[str1] += sign * t1[ia*bcount+str0];
                         }
+                        pci[str1] += sign * t1[ia*bcount+str0];
                 }
                 tab += nlinkb;
         }
diff --git a/pyscf/lib/mcscf/fci_string.c b/pyscf/lib/mcscf/fci_string.c
index 2110c493aa..adae90da46 100644
--- a/pyscf/lib/mcscf/fci_string.c
+++ b/pyscf/lib/mcscf/fci_string.c
@@ -136,6 +136,7 @@ static int binomial(int n, int m)
                         val *= i;
                         val /= i - m;
                 }
+                return val;
         }
 }