diff --git a/matrix/bulk_operate.cpp b/matrix/bulk_operate.cpp
index 744d57f6..4a3a6bb2 100644
--- a/matrix/bulk_operate.cpp
+++ b/matrix/bulk_operate.cpp
@@ -84,7 +84,7 @@ class basic_uops_impl: public basic_uops
 			return "abs";
 		}
 		OutType operator()(const InType &e) const {
-			return (OutType) std::abs(e);
+            return e < 0 ?  ((OutType) -e) : ((OutType) e);
 		}
 	};
 
diff --git a/matrix/data_io.cpp b/matrix/data_io.cpp
index 4deb389e..09919171 100644
--- a/matrix/data_io.cpp
+++ b/matrix/data_io.cpp
@@ -275,7 +275,7 @@ std::shared_ptr<char> gz_file_io::read_bytes(
 		if (ret <= 0) {
 			if (ret < 0 || !gzeof(f)) {
 				BOOST_LOG_TRIVIAL(fatal) << gzerror(f, &ret);
-				return std::unique_ptr<char[]>();
+                return std::unique_ptr<char>();
 			}
 		}
 		read_bytes += ret;
@@ -402,7 +402,7 @@ static size_t parse_lines(std::shared_ptr<char> line_buf, size_t size,
 	}
 	if (line - buf_start < (ssize_t) size)
 		lines.push_back(std::string(line));
-	
+
 	return parser.parse(lines, df);
 }