%                 Aysajan Abidin
%                 November 25th, 2005 - Asta Herdis Hall
%
%     File:  para.m
%
%     Here, we describe all input variables that occur repeatedly when
%     computing the solution of the stochastic heat equation.
%
%   alfa:    Gives the value of the index -alfa, alfa != 1 gives
%            nuclear Wiener process and alfa = 1 gives time-space 
%            white noise. alfa in (0,infinity) guarantees existence
%            and uniqueness of a solution to the spde with sigma=I in 2D.
%     u0:    Initial conditions, i.e. an approximation of the
%            solution to the spde at time t=0.
%
%  PARAMETERS CONCERNING THE TIME INTERVAL:
%      Note: We compute FEM solutions for as many different partitions
%            of the time interval as is desired.
%      K:    The number of time steps in the finest time partition.
%            The length of each time step is dt = T/K, where T is 
%            described below. 
%            The finest means the best possible space and time partitions
%            for which the specific computer can affort the computational
%            power. In our test we take H = 2^11 and K = 2^11
%      T:    Final timepoint.
%     t0:    Initial timepoint.
%      R:    A vector specifying for how many different time 
%            partitions we compute the Wiener process.  Also,
%            it specifies the length of each time interval.
%            Example: R=[1,4,8,16,32,64,128].  This means that there
%            are 7 intervals of different length, each of length
%            Dt = R(i)*dt, where dt = T/K.  Note that we must have
%            that mod(K,R(i)) = 0 for all i.
%  MESH PARAMETERS:
%
%      TAG:       Represents the spatial dimension. 
%        
%        If TAG = 1, then
%        p:       1 x n vector of node coordinates.
%              
%        t:       3 x m matrix of element node numbers t(1,el)=nn1
%                 and t(2,el)=nn2, 1 <= el <= m, pointing to 
%                 corresponding node coordinates p(nn1) and p(nn2),
%                 and subdomain reference tags t(3,el), useful
%                 if data are given by different expresssions in
%                 different parts of the domain.
%
%        e:       2 x 2 matrix of boundary node numbers and 
%                 reference tags, with node number e(1,1)=nn pointing
%                 to the left boundary node coordinate p(nn), and e(2,2)
%                 is a reference tag (see example below).       
%
%        If TAG = 2, then
%        p,e,t:   Information about the space mesh (p=points, e=edges,
%                 t=triangles). For further information try: help initmesh
