Added a missing assert.

dlib/svm/structural_svm_sequence_labeling_problem.h

@@ -84,6 +84,34 @@ namespace dlib
             labels(labels_),
             fe(fe_)
         {
+            // make sure requires clause is not broken
+            DLIB_ASSERT(is_sequence_labeling_problem(samples,labels) == true,
+                        "\t structural_svm_sequence_labeling_problem::structural_svm_sequence_labeling_problem()"
+                        << "\n\t invalid inputs were given to this function"
+                        << "\n\t samples.size(): " << samples.size() 
+                        << "\n\t is_sequence_labeling_problem(samples,labels): " << is_sequence_labeling_problem(samples,labels)
+                        << "\n\t this: " << this
+                        );
+
+#ifdef ENABLE_ASSERTS
+            for (unsigned long i = 0; i < labels.size(); ++i)
+            {
+                for (unsigned long j = 0; j < labels[i].size(); ++j)
+                {
+                    // make sure requires clause is not broken
+                    DLIB_ASSERT(labels[i][j] < fe.num_labels(),
+                                "\t structural_svm_sequence_labeling_problem::structural_svm_sequence_labeling_problem()"
+                                << "\n\t The given labels in labels are invalid."
+                                << "\n\t labels[i][j]: " << labels[i][j] 
+                                << "\n\t fe.num_labels(): " << fe.num_labels()
+                                << "\n\t i: " << i 
+                                << "\n\t j: " << j 
+                                << "\n\t this: " << this
+                                );
+                }
+            }
+#endif
+
         }
 
     private: