Added gaussian_randm()

dlib/matrix/matrix_utilities.h

@@ -16,7 +16,7 @@
 #include "matrix_expressions.h"
 #include "matrix_math_functions.h"
 #include "matrix_op.h"
-#include "../general_hash/murmur_hash3.h"
+#include "../general_hash/random_hashing.h"
 
 
 namespace dlib
@@ -2064,6 +2064,43 @@ namespace dlib
         return matrix_op<op>(op());
     }
 
+// ----------------------------------------------------------------------------------------
+
+    struct op_gaussian_randm : does_not_alias 
+    {
+        op_gaussian_randm (
+            long nr_,
+            long nc_,
+            unsigned long seed_
+        ) :_nr(nr_), _nc(nc_), seed(seed_){}
+
+        const long _nr;
+        const long _nc;
+        const unsigned long seed;
+
+        const static long cost = 100;
+        const static long NR = 0;
+        const static long NC = 0;
+        typedef default_memory_manager mem_manager_type;
+        typedef row_major_layout layout_type;
+        typedef double type;
+        typedef double const_ret_type;
+        const_ret_type apply ( long r, long c) const { return gaussian_random_hash(r,c,seed); }
+
+        long nr() const { return _nr; }
+        long nc() const { return _nc; }
+    };
+
+    inline const matrix_op<op_gaussian_randm> gaussian_randm (
+        long nr,
+        long nc,
+        unsigned long seed = 0
+    )
+    {
+        typedef op_gaussian_randm op;
+        return matrix_op<op>(op(nr,nc,seed));
+    }
+
 // ----------------------------------------------------------------------------------------
 
     template <typename M>

dlib/matrix/matrix_utilities_abstract.h

@@ -1618,6 +1618,33 @@ namespace dlib
                     - M(i,j) == a random number such that 0 <= M(i,j) < 1
     !*/
 
+// ----------------------------------------------------------------------------------------
+
+    inline const matrix_exp gaussian_randm (
+        long nr,
+        long nc,
+        unsigned long seed = 0
+    );
+    /*!
+        requires
+            - nr >= 0
+            - nc >= 0
+        ensures
+            - returns a matrix with its values filled with 0 mean unit variance Gaussian
+              random numbers.  
+            - Each setting of the seed results in a different random matrix.
+            - The returned matrix is lazily evaluated using the expression templates
+              technique.  This means that the returned matrix doesn't take up any memory
+              and is only an expression template.  The values themselves are computed on
+              demand using the gaussian_random_hash() routine.  
+            - returns a matrix M such that
+                - M::type == double
+                - M.nr() == nr
+                - M.nc() == nc
+                - for all valid i, j:
+                    - M(i,j) == gaussian_random_hash(i,j,seed) 
+    !*/
+
 // ----------------------------------------------------------------------------------------
 // ----------------------------------------------------------------------------------------
 //                                 Pixel and Image Utilities