Refined interface for Conjugate Gradient

Some interface was refined (most notably, the method for returning
Hessian was removed and the method for getting gradient was added as
optional to base Solver::Function class) and basic code for
setters/getters was added. Now is the time for the real work on an
algorithm.

modules/optim/src/simplex.cpp

@@ -19,6 +19,8 @@ namespace cv{namespace optim{
         Ptr<Solver::Function> _Function;
         TermCriteria _termcrit;
         Mat _step;
+        Mat_<double> buf_x;
+
     private:
         inline void createInitialSimplex(Mat_<double>& simplex,Mat& step);
         inline double innerDownhillSimplex(cv::Mat_<double>& p,double MinRange,double MinError,int& nfunk,
@@ -209,7 +211,10 @@ namespace cv{namespace optim{
         Mat_<double> proxy_x;
 
         if(x_mat.rows>1){
-            proxy_x=x_mat.t();
+            buf_x.create(1,_step.cols);
+            Mat_<double> proxy(_step.cols,1,(double*)buf_x.data);
+            x_mat.copyTo(proxy);
+            proxy_x=buf_x;
         }else{
             proxy_x=x_mat;
         }