fixed incorrect tests

dlib/test/matrix3.cpp

@@ -1085,28 +1085,28 @@ namespace
 
         matrix<double> p = g + tau*dlib::colm(B,0);
         matrix<double> q = dlib::colm(B,0);
-        DLIB_TEST(length(p-q) < 1e-14);
+        DLIB_TEST(max(abs(p-q)) < 1e-14);
 
         p = tau*dlib::colm(B,0);
         q = dlib::colm(B,0);
-        DLIB_TEST(length(p-q) < 1e-14);
+        DLIB_TEST(max(abs(p-q)) < 1e-14);
 
 
 
 
         g = dlib::uniform_matrix<double>(n,n,0.0);
         p = g + tau*B;
-        DLIB_TEST(length(p-B) < 1e-14);
+        DLIB_TEST(max(abs(p-B)) < 1e-14);
 
         p = g + tau*subm(B,get_rect(B));
-        DLIB_TEST(length(p-B) < 1e-14);
+        DLIB_TEST(max(abs(p-B)) < 1e-14);
 
         g = dlib::uniform_matrix<double>(2,2,0.0);
         p = g + tau*subm(B,1,1,2,2);
-        DLIB_TEST(length(p-subm(B,1,1,2,2)) < 1e-14);
+        DLIB_TEST(max(abs(p-subm(B,1,1,2,2))) < 1e-14);
 
         set_subm(p,0,0,2,2) = g + tau*subm(B,1,1,2,2);
-        DLIB_TEST(length(p-subm(B,1,1,2,2)) < 1e-14);
+        DLIB_TEST(max(abs(p-subm(B,1,1,2,2))) < 1e-14);
     }