diff --git a/pyrost/bin/st_utils.pyx b/pyrost/bin/st_utils.pyx
index d141dccd0e86f327df6c50fdea5021aea38b3f35..bbd09ae75651aab492bd6391d655bb6fe63ca7bc 100755
--- a/pyrost/bin/st_utils.pyx
+++ b/pyrost/bin/st_utils.pyx
@@ -12,6 +12,7 @@ ctypedef fused float_t:
 
 ctypedef np.uint64_t uint_t
 ctypedef np.npy_bool bool_t
+ctypedef np.complex128_t complex_t
 
 DEF FLOAT_MAX = 1.7976931348623157e+308
 DEF MU_C = 1.681792830507429