bugfixed grid generation and numerical gradient computation in DerivateBasedOptimizer::geNumericalGradient

DerivativeBasedOptimizer.cpp

@@ -4,7 +4,7 @@
 //				  Optimizer class.
 //
 //	Written by Matthias Wacker
-//
+//  	edited by Johannes Ruehle, 2012-10-11
 //////////////////////////////////////////////////////////////////////
 
 #include "optimization/DerivativeBasedOptimizer.h"
@@ -63,24 +63,25 @@ const matrix_type  DerivativeBasedOptimizer::getNumericalGradient(const matrix_t
 
 	for(int i=0; i < static_cast<int>(m_numberOfParameters);i++)
 	{
-		for(int j = 0 ; j< 2 * static_cast<int>(m_numberOfParameters);j++)
-		{
-			grid[i][j] = x[i][0] + ((j == i)? maskWidth[i][0] : 0.0)
-				+ ((j == i+1)? maskWidth[i][0] *(-1.0): 0.0);
-		}
+	    for(int j = 0 ; j< 2 * static_cast<int>(m_numberOfParameters);j++)
+	    {
+		grid[i][j] = x[i][0] + (( j == i*2   )? +maskWidth[i][0] : 0.0)
+                                     + (( j == i*2+1 )? -maskWidth[i][0] : 0.0);
+	    }
 	}
 	
 	matrix_type values = evaluateSetCostFunction(grid);
 		
 	for(int i=0; i < static_cast<int>(m_numberOfParameters);i++)
 	{
-		grad[i][0] = ( values[i][0] - values[i+1][0] )/( 2 * maskWidth[i][0]);
+	    if(m_scales[i][0] == 0 )
+	    {
+		grad[i][0] = 0;
+		continue;
+	    }
+        
+	    grad[i][0] = ( values[2*i][0] - values[2*i+1][0] )/( 2 * maskWidth[i][0]);
 		
-		if(m_scales[i][0] == 0 )
-		{
-			grad[i][0] = 0;
-			continue;
-		}
 	}
 	
 	return grad;