%-------------------------------------------------------------------------------
% SuiteSparse Matrix Collection, Tim Davis
% https://sparse.tamu.edu/Guettel/TEM152078
% name: Guettel/TEM152078
% [3D transient electromagnetic modelling, S. Guettel, Univ Manchester]
% id: 2812
% date: 2015
% author: R.-U. B\"orner, O. G. Ernst, S. G\"uttel
% ed: T. Davis
% fields: name title A id date author ed kind notes aux
% aux: M q
% kind: electromagnetics problem
%-------------------------------------------------------------------------------
% notes:
% 3D Transient Electromagnetic Modelleing, Stefan Guettel, Univ Manchester
%                                                                         
% The TEM problem relates to the time-dependent modelling of a transient  
% electromagnetic field in geophysical exploration. The set contains a    
% matrix pencil (C,M) and an initial value vector q, corresponding to a   
% Nedelec finite element discretization of Maxwell's equations for the    
% electric field density e(t). The curl-curl matrix C is symmetric        
% positive semi-definite and the mass matrix M is symmetric positive      
% definite. The problem to be solved is a linear initial value problem    
%                                                                         
%    M*e'(t) = C*e(t),  M*e(0) = q,                                       
%                                                                         
% for logarithmically distributed time points t in the interval           
% [1e-6,1e-3].                                                            
%                                                                         
% There are three test sets which are described in the following          
% publication:                                                            
%                                                                         
% @article{BEG2015,                                                       
%   title={Three-dimensional transient electromagnetic modelling using    
%     rational {K}rylov methods},                                         
%   author={B{\"o}rner, Ralph-Uwe and Ernst, Oliver G and G{\"u}ttel,     
%     Stefan},                                                            
%   journal={Geophysical Journal International},                          
%   volume={202},                                                         
%   number={3},                                                           
%   pages={2025--2043},                                                   
%   year={2015},                                                          
%   publisher={Oxford University Press}                                   
% }                                                                       
%                                                                         
% The problem details are                                                 
%                                                                         
% TEM27623: section 5.1 in the above paper; layered half-space problem    
% discretized by 24582 tetrahedral elements of order 1 giving rise to     
% 27623 degrees of freedom.                                               
%                                                                         
% TEM152078: section 5.1 in the above paper; layered half-space problem   
% discretized by 24582 tetrahedral elements of order 2 giving rise to     
% 152078 degrees of freedom.                                              
%                                                                         
% TEM181302: section 5.2 in the above paper; homogeneous subsurface with  
% topography discretized by 28849 tetrahedral elements of order 2 giving  
% rise to 181302 degrees of freedom.                                      
%                                                                         
% In the SuiteSparse Matrix Collection, the primary matrix Problem.A is   
% the matrix C in the TEM* problems.  The M matrix appears as             
% Problem.aux.M, and the q vector is Problem.aux.q.                       
%-------------------------------------------------------------------------------
