diff --git a/src_main/containers/pivector.h b/src_main/containers/pivector.h
index 5a0ff2c7..454d8497 100755
--- a/src_main/containers/pivector.h
+++ b/src_main/containers/pivector.h
@@ -173,7 +173,7 @@ public:
 	inline bool operator !=(const PIVector<T> & t) const {if (piv_size != t.piv_size) return true; for (size_t i = 0; i < piv_size; ++i) if (t[i] != piv_data[i]) return true; return false;}
 	inline bool contains(const T & v) const {for (size_t i = 0; i < piv_size; ++i) if (v == piv_data[i]) return true; return false;}
 	inline int etries(const T & v) const {int ec = 0; for (size_t i = 0; i < piv_size; ++i) if (v == piv_data[i]) ++ec; return ec;}
-	inline ssize_t indexOf(const T & v) const {for (ssize_t i = 0; i < piv_size; ++i) if (v == piv_data[i]) return i; return -1;}
+	inline ssize_t indexOf(const T & v) const {for (size_t i = 0; i < piv_size; ++i) if (v == piv_data[i]) return i; return -1;}
 	inline ssize_t lastIndexOf(const T & v) const {for (ssize_t i = piv_size - 1; i >= 0; --i) if (v == piv_data[i]) return i; return -1;}
 
 	inline T * data(size_t index = 0) {return &(piv_data[index]);}