diff --git a/qlat/auto_contractor/compile.py b/qlat/auto_contractor/compile.py
index 004a370a..472f0a36 100644
--- a/qlat/auto_contractor/compile.py
+++ b/qlat/auto_contractor/compile.py
@@ -1401,6 +1401,7 @@ class CExprCodeGenPy:
     self.indent
     self.total_sloppy_flops
     #
+    flops per complex addition: 2
     flops per complex multiplication: 6
     flops per matrix multiplication: 6 M N L + 2 M L (N-1) ==> 13536 (sc * sc), 4320 (sc * s), 480 (s * s), 3168 (sc * c), 198 (c * c)
     flops per trace 2 (M-1) ==> 22 (sc)
@@ -1886,16 +1887,29 @@ def cexpr_function_bs_eval(self):
                 append_cy(f"cdef cc.PyComplexD {name}_v = 0")
                 append_py(f"{name} = 0")
             ch1, ch2, ch3, = chain_list
+            def get_ss_tag(ss):
+                return "_".join([ str(s) for s in ss ])
+            ss_dict = dict()
+            for bs in bs_list:
+                elem_list = bs.get_spin_spin_tensor_elem_list_code()
+                for ss, coef, in elem_list:
+                    if ss in ss_dict:
+                        continue
+                    ss_name = f"ss_res_{get_ss_tag(ss)}"
+                    ss_dict[ss] = ss_name
+                    v_s1, b_s1, v_s2, b_s2, v_s3, b_s3, = ss
+                    append_cy(f"cdef cc.PyComplexD {ss_name} = cc.pycc_d(cc.epsilon_contraction({v_s1}, {b_s1}, {v_s2}, {b_s2}, {v_s3}, {b_s3}, {ch1}[0], {ch2}[0], {ch3}[0]))")
+                    append_py(f"{ss_name} = mat_epsilon_contraction_wm_wm_wm({v_s1}, {b_s1}, {v_s2}, {b_s2}, {v_s3}, {b_s3}, {ch1}, {ch2}, {ch3})")
+                    self.total_sloppy_flops += 504 # 6 * 6 * (2 * 6 + 2)
             for name, bs in zip(name_list, bs_list):
                 elem_list = bs.get_spin_spin_tensor_elem_list_code()
                 for ss, coef, in elem_list:
+                    ss_name = f"ss_res_{get_ss_tag(ss)}"
                     c, t, = self.gen_expr(coef)
                     assert t == "V_a"
-                    v_s1, b_s1, v_s2, b_s2, v_s3, b_s3, = ss
-                    append_cy(f"v = cc.pycc_d(cc.epsilon_contraction({v_s1}, {b_s1}, {v_s2}, {b_s2}, {v_s3}, {b_s3}, {ch1}[0], {ch2}[0], {ch3}[0]))")
-                    append_py(f"v = mat_epsilon_contraction_wm_wm_wm({v_s1}, {b_s1}, {v_s2}, {b_s2}, {v_s3}, {b_s3}, {ch1}, {ch2}, {ch3})")
-                    append_cy(f"{name}_v += ({c}) * v")
-                    append_py(f"{name} += ({c}) * v")
+                    append(f"v = {c}")
+                    append_cy(f"{name}_v += v * {ss_name}")
+                    append_py(f"{name} += v * {ss_name}")
             for name in name_list:
                 append_cy(f"{name}[0] = {name}_v")
             name_list_str = ", ".join(name_list)