[T] Rewrite loop to avoid implicit conversions.

Tests/GeoLib/TestOctTree.cpp

@@ -298,11 +298,11 @@ TEST_F(GeoLibOctTree, TestSmallDistanceDifferentLeaves)
 	// case where two points with a small distance but different OctTree leaves
 	// are inserted
 	double const eps(0.5);
-	for (int k(-10); k<11; ++k) {
-		for (int j(-10); j<11; ++j) {
-			std::size_t id((k+10)*21+(j+10));
-			for (int i(-10); i<11; ++i) {
-				ps_ptr.push_back(new GeoLib::Point(1.0*i, 1.0*j, 1.0*k, id+i+10));
+	for (std::size_t k = 0; k < 21; ++k) {
+		for (std::size_t j = 0; j < 21; ++j) {
+			std::size_t id = k*21+j;
+			for (std::size_t i = 0; i < 21; ++i) {
+				ps_ptr.push_back(new GeoLib::Point(i-10., j-10., k-10., id+i));
 			}
 		}
 	}