Added a matrix constructor that takes an initializer list.

dlib/matrix/matrix.h

@@ -16,6 +16,9 @@
 #include "matrix_assign_fwd.h"
 #include "matrix_op.h"
 #include <utility>
+#ifdef DLIB_HAS_RVALUE_REFERENCES
+#include <initializer_list>
+#endif
 
 #ifdef MATLAB_MEX_FILE
 #include <mex.h>
@@ -1112,6 +1115,55 @@ namespace dlib
         }
 
 #ifdef DLIB_HAS_RVALUE_REFERENCES
+        matrix(const std::initializer_list<T>& l)
+        {
+            if (NR*NC != 0)
+            {
+                DLIB_ASSERT(l.size() == NR*NC, 
+                    "\t matrix::matrix(const std::initializer_list& l)"
+                    << "\n\t You are trying to initialize a statically sized matrix with a list that doesn't have a matching size."
+                    << "\n\t l.size(): "<< l.size()
+                    << "\n\t NR*NC:    "<< NR*NC);
+
+                data.set_size(NR, NC);
+            }
+            else if (NR!=0) 
+            {
+                DLIB_ASSERT(l.size()%NR == 0, 
+                    "\t matrix::matrix(const std::initializer_list& l)"
+                    << "\n\t You are trying to initialize a statically sized matrix with a list that doesn't have a compatible size."
+                    << "\n\t l.size(): "<< l.size()
+                    << "\n\t NR:       "<< NR);
+
+                if (l.size() != 0)
+                    data.set_size(NR, l.size()/NR);
+            }
+            else if (NC!=0) 
+            {
+                DLIB_ASSERT(l.size()%NC == 0, 
+                    "\t matrix::matrix(const std::initializer_list& l)"
+                    << "\n\t You are trying to initialize a statically sized matrix with a list that doesn't have a compatible size."
+                    << "\n\t l.size(): "<< l.size()
+                    << "\n\t NC:       "<< NC);
+
+                if (l.size() != 0)
+                    data.set_size(l.size()/NC, NC);
+            }
+            else if (l.size() != 0)
+            {
+                data.set_size(l.size(),1);
+            }
+
+            if (l.size() != 0)
+            {
+                T* d = &data(0,0);
+                for (auto&& v : l)
+                    *d++ = v;
+            }
+
+        }
+
+
         matrix(matrix&& item)
         {
         #ifdef MATLAB_MEX_FILE

dlib/matrix/matrix_abstract.h

@@ -337,6 +337,30 @@ namespace dlib
                 - #ref().aliases(*this) == true
         !*/
         
+        matrix(
+            const std::initializer_list<T>& l
+        );
+        /*!
+            requires
+                - This matrix is capable of having a size() == l.size().  Therefore, if
+                  NR*NC != 0 then l.size() must equal NR*NC.  Alternatively, if NR or NC is
+                  != 0 then l.size() must be a multiple of the non-zero NR or NC.
+            ensures
+                - #size() == l.size()
+                - The contents of l are enumerated and read into the matrix in row major order.
+                - if (NR != 0) then
+                    - #nr() == NR
+                    - #nc() == l.size()/NR
+                - if (NC != 0) then
+                    - #nr() == l.size()/NC
+                    - #nc() == NC
+                - if (NR*NC==0) then
+                    - #nr() == l.size()
+                    - #nc() == 1
+                - #aliases(*this) == true
+                - #ref().aliases(*this) == true
+        !*/
+
         T& operator() (
             long r, 
             long c