Added compile time checks that make it so the user gets a much more informative

error message if they mistakenly use matrices that are not column vectors with
the general purpose optimizers.

dlib/optimization/optimization.h

@@ -181,6 +181,9 @@ namespace dlib
     )
     {
         COMPILE_TIME_ASSERT(is_matrix<T>::value);
+        // The starting point (i.e. x) must be a column vector.  
+        COMPILE_TIME_ASSERT(T::NC <= 1);
+
         DLIB_ASSERT (
             is_col_vector(x),
             "\tdouble find_min()"
@@ -238,6 +241,9 @@ namespace dlib
     )
     {
         COMPILE_TIME_ASSERT(is_matrix<T>::value);
+        // The starting point (i.e. x) must be a column vector.  
+        COMPILE_TIME_ASSERT(T::NC <= 1);
+
         DLIB_ASSERT (
             is_col_vector(x),
             "\tdouble find_max()"
@@ -302,6 +308,9 @@ namespace dlib
     )
     {
         COMPILE_TIME_ASSERT(is_matrix<T>::value);
+        // The starting point (i.e. x) must be a column vector.  
+        COMPILE_TIME_ASSERT(T::NC <= 1);
+
         DLIB_ASSERT (
             is_col_vector(x) && derivative_eps > 0,
             "\tdouble find_min_using_approximate_derivatives()"
@@ -362,6 +371,9 @@ namespace dlib
     )
     {
         COMPILE_TIME_ASSERT(is_matrix<T>::value);
+        // The starting point (i.e. x) must be a column vector.  
+        COMPILE_TIME_ASSERT(T::NC <= 1);
+
         DLIB_ASSERT (
             is_col_vector(x) && derivative_eps > 0,
             "\tdouble find_max_using_approximate_derivatives()"
@@ -463,6 +475,9 @@ namespace dlib
 
         // make sure the requires clause is not violated
         COMPILE_TIME_ASSERT(is_matrix<T>::value);
+        // The starting point (i.e. x) must be a column vector.  
+        COMPILE_TIME_ASSERT(T::NC <= 1);
+
         DLIB_ASSERT (
             is_col_vector(x) && is_col_vector(x_lower) && is_col_vector(x_upper) &&
             x.size() == x_lower.size() && x.size() == x_upper.size(),
@@ -548,6 +563,9 @@ namespace dlib
         double x_upper
     )
     {
+        // The starting point (i.e. x) must be a column vector.  
+        COMPILE_TIME_ASSERT(T::NC <= 1);
+
         typedef typename T::type scalar_type;
         return find_min_box_constrained(search_strategy,
                                         stop_strategy,
@@ -581,6 +599,9 @@ namespace dlib
     {
         // make sure the requires clause is not violated
         COMPILE_TIME_ASSERT(is_matrix<T>::value);
+        // The starting point (i.e. x) must be a column vector.  
+        COMPILE_TIME_ASSERT(T::NC <= 1);
+
         DLIB_ASSERT (
             is_col_vector(x) && is_col_vector(x_lower) && is_col_vector(x_upper) &&
             x.size() == x_lower.size() && x.size() == x_upper.size(),
@@ -673,6 +694,9 @@ namespace dlib
         double x_upper
     )
     {
+        // The starting point (i.e. x) must be a column vector.  
+        COMPILE_TIME_ASSERT(T::NC <= 1);
+
         typedef typename T::type scalar_type;
         return find_max_box_constrained(search_strategy,
                                         stop_strategy,

dlib/optimization/optimization_bobyqa.h

@@ -3353,6 +3353,9 @@ L210:
         const long max_f_evals
     ) 
     {
+        // The starting point (i.e. x) must be a column vector.  
+        COMPILE_TIME_ASSERT(T::NC <= 1);
+
         // check the requirements.  Also split the assert up so that the error message isn't huge.
         DLIB_CASSERT(is_col_vector(x) && is_col_vector(x_lower) && is_col_vector(x_upper) &&
                     x.size() == x_lower.size() && x_lower.size() == x_upper.size() &&
@@ -3405,6 +3408,9 @@ L210:
         const long max_f_evals
     ) 
     {
+        // The starting point (i.e. x) must be a column vector.  
+        COMPILE_TIME_ASSERT(T::NC <= 1);
+
         return -find_min_bobyqa(negate_function(f), x, npt, x_lower, x_upper, rho_begin, rho_end, max_f_evals);
     }
 

dlib/optimization/optimization_least_squares.h

@@ -190,6 +190,9 @@ namespace dlib
         double radius = 1
     )
     {
+        // The starting point (i.e. x) must be a column vector.  
+        COMPILE_TIME_ASSERT(T::NC <= 1);
+
         // make sure requires clause is not broken
         DLIB_ASSERT(is_vector(mat(list)) && list.size() > 0 && 
                     is_col_vector(x) && radius > 0,
@@ -313,6 +316,9 @@ namespace dlib
         double radius = 1
     )
     {
+        // The starting point (i.e. x) must be a column vector.  
+        COMPILE_TIME_ASSERT(T::NC <= 1);
+
         // make sure requires clause is not broken
         DLIB_ASSERT(is_vector(mat(list)) && list.size() > 0 && 
                     is_col_vector(x) && radius > 0,