M1 Mathematics, 2011-2012   
 MM26E Numerical Approximation of PDEs       Hervé Le Dret
      
      
      $Q_3$-Hermite approximation
    
      Below are the graphs of various basis polynomials of $Q_3$-Hermite interpolation on the unit square $[0,1]^2$.
      
  
             
       
      
  
      $(x_1,x_2)\mapsto (1+2x_1)(1-x_1)^2(1+2x_2)(1-x_2)^2$
             
		 
  
             
  
             
       
            
  
            $(x_1,x_2)\mapsto (1+2x_1)(1-x_1)^2x_2(1-x_2)^2$
                  
 		 
  
              
  
             
       
                  
  
$(x_1,x_2)\mapsto x_1(x_2-1)(1-x_1)^2x_2^2$
            
		 
  
 
 And the corresponding $C^1$ hat functions (compare with the $Q_2$ only $C^0$ hat functions), constructed by patching together four copies of each of the shape functions above on four contiguous rectangles:
 
               
  
             
       
                  
  
              
  
             
       
                  
  
              
  
             
       
                  
  
 |