%%%%% Begin file compute_eigs.m
function [eigval,eigvec] = compute_eigs(k,m,n)
Globals;
ASphi = sparse(K*Np,K*Np);  ASp = ASphi;
APphi = ASphi;              APp = ASphi;
g = sparse(K*Np,1);
% Build matrix -- one column at a time
for i=1:K*Np
    g(i) = 1.0;    
    % solid equation
    ASphi(:,i) = -m*g - ggamma/delta*ddz(g,0)  + n*g;
    ASp(:,i)   = g   - delta*ddz(g,1);
    % pressure equation
    APphi(:,i) = n*ddz(g,0);
    APp(:,i)   = delta*(k^2*g-ddz2(g)); 
    g(i)=0.0;
end
ptildeOp  = -inv(APp)*APphi; S = ASphi+ASp*ptildeOp;
[VV,DD]=eig(full(S)); DD = diag(DD);
ii = find(real(DD)==max(real(DD))); ii = ii(1);
eigval = DD(ii); eigvec = VV(:,ii)/max(abs(real(VV(:,ii))));
end
%%%%% End file compute_eigs.m