Authors: Carlo Janna and Massimiliano Ferronato                 
                                                                
Symmetric Positive Definite Matrix                              
# equations:  923136                                            
# non-zeroes: 41005206                                          
Problem description: Geomechanical problem                      
                                                                
The matrix Emilia_923 is obtained from a structural problem     
discretizing a gas reservoir with tetrahedral Finite Elements.  
Due to the complex geometry of the geological formation it was  
not possible to obtain a computational grid characterized by    
regularly shaped elements.  The problem arises from a 3D        
discretization with three displacement unknowns associated to   
each node of the grid.  Some further information may be found in
the following papers:                                           
                                                                
1) M. Ferronato, G. Gambolati, C. Janna, P. Teatini.            
"Geomechanical issues of anthropogenic CO2 sequestration in     
exploited gas fields", Energy Conversion and Management, 51, pp.
1918-1928, 2010.                                                
                                                                
2) C. Janna, M. Ferronato. "Adaptive pattern research for block 
FSAI preconditionig". SIAM Journal on Scientific Computing, to  
appear.