code: private int addView( DMatrixRMaj P , Point2D_F64 a , int index ) {
  
  		final double sx = stats.stdX, sy = stats.stdY;
  //		final double cx = stats.meanX, cy = stats.meanY;
  
  
  		// Easier to read the code when P is broken up this way
  		double r11 = P.data[0], r12 = P.data[1], r13 = P.data[2],  r14=P.data[3];
  		double r21 = P.data[4], r22 = P.data[5], r23 = P.data[6],  r24=P.data[7];
  		double r31 = P.data[8], r32 = P.data[9], r33 = P.data[10], r34=P.data[11];
  
  		// These rows are derived by applying the scaling matrix to pixels and camera matrix
  		// px = (a.x/sx - cx/sx)
  		// A[0,0] = a.x*r31 - r11            (before normalization)
  		// A[0,0] = px*r31 - (r11-cx*r31)/sx (after normalization)
  
  		// first row
  		A.data[index++] = (a.x*r31-r11)/sx;
  		A.data[index++] = (a.x*r32-r12)/sx;
  		A.data[index++] = (a.x*r33-r13)/sx;
  		A.data[index++] = (a.x*r34-r14)/sx;
  
  		// second row
  		A.data[index++] = (a.y*r31-r21)/sy;
  		A.data[index++] = (a.y*r32-r22)/sy;
  		A.data[index++] = (a.y*r33-r23)/sy;
  		A.data[index++] = (a.y*r34-r24)/sy;
  
  		return index;
  	}
docs: Adds a view to the A matrix. Computed using cross product.