You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: subsolv.m
    path of file: ./repos/Swan/TopOptEig/OptimalBucklingColumn
    
    the code of the file until where you have to start completion: %    This is the file subsolv.m
%
function [xmma,ymma,zmma,lamma,xsimma,etamma,mumma,zetmma,smma] = ...
subsolv(m,n,epsimin,low,upp,alfa,beta,p0,q0,P,Q,a0,a,b,c,d);
%
%    Written in May 1999 by
%    Krister Svanberg <krille@math.kth.se>
%    Department of Mathematics
%    SE-10044 Stockholm, Sweden.
%
% This function subsolv solves the MMA subproblem:
%         
% minimize   SUM[ p0j/(uppj-xj) + q0j/(xj-lowj) ] + a0*z +
%          + SUM[ ci*yi + 0.5*di*(yi)^2 ],
%
% subject to SUM[ pij/(uppj-xj) + qij/(xj-lowj) ] - ai*z - yi <= bi,
%            alfaj <=  xj <=  betaj,  yi >= 0,  z >= 0.
%        
% Input:  m, n, low, upp, alfa, beta, p0, q0, P, Q, a0, a, b, c, d.
% Output: xmma,ymma,zmma, slack variables and Lagrange multiplers.
%
een = ones(n,1);
eem = ones(m,1);
epsi = 1;
epsvecn = epsi*een;
epsvecm = epsi*eem;
x = 0.5*(alfa+beta);
y = eem;
z = 1;
lam = eem;
xsi = een./(x-alfa);
xsi = max(xsi,een);
eta = een./(beta-x);
eta = max(eta,een);
mu  = max(eem,0.5*c);
zet = 1;
s = eem;
itera = 0;

while epsi > epsimin
  epsvecn = epsi*een;
  epsvecm = epsi*eem;
  ux1 = upp-x;
  xl1 = x-low;
  ux2 = ux1.*ux1;
  xl2 = xl1.*xl1;
  uxinv1 = een./ux1;
  xlinv1 = een./xl1;

  plam = p0 + P'*lam ;
  qlam = q0 + Q'*lam ;
  gvec = P*uxinv1 + Q*xlinv1;
  dpsidx = plam./ux2 - qlam./xl2 ;

  rex = dpsidx - xsi + eta;
  rey = c + d.*y - mu - lam;
  rez = a0 - zet - a'*lam;
  relam = gvec - a*z - y + s - b;
  rexsi = xsi.*(x-alfa) - epsvecn;
  reeta = eta.*(beta-x) - epsvecn;
  remu = mu.*y - epsvecm;
  rezet = zet*z - epsi;
  res = lam.*s - epsvecm;

  residu1 = [rex' rey' rez]';
  residu2 = [relam' rexsi' reeta' remu' rezet res']';
  residu = [residu1' residu2']';
  residunorm = sqrt(residu'*residu);
  residumax = max(abs(residu));

  ittt = 0;
  while residumax > 0.9*epsi & ittt < 100
    it
    
function [xmma,ymma,zmma,lamma,xsimma,etamma,mumma,zetmma,smma] = ...
subsolv(m,n,epsimin,low,upp,alfa,beta,p0,q0,P,Q,a0,a,b,c,d);
%
%    Written in May 1999 by
%    Krister Svanberg <krille@math.kth.se>
%    Department of Mathematics
%    SE-10044 Stockholm, Sweden.
%
% This function subsolv solves the MMA subproblem:
%         
% minimize   SUM[ p0j/(uppj-xj) + q0j/(xj-lowj) ] + a0*z +
%          + SUM[ ci*yi + 0.5*di*(yi)^2 ],
%
% subject to SUM[ pij/(uppj-xj) + qij/(xj-lowj) ] - ai*z - yi <= bi,
%            alfaj <=  xj <=  betaj,  yi >= 0,  z >= 0.
%        
% Input:  m, n, low, upp, alfa, beta, p0, q0, P, Q, a0, a, b, c, d.
% Output: xmma,ymma,zmma, slack variables and Lagrange multiplers.
%
een = ones(n,1);
eem = ones(m,1);
epsi = 1;
epsvecn = epsi*een;
epsvecm = epsi*eem;
x = 0.5*(alfa+beta);
y = eem;
z = 1;
lam = eem;
xsi = een./(x-alfa);
xsi = max(xsi,een);
eta = een./(beta-x);
eta = max(eta,een);
mu  = max(eem,0.5*c);
zet = 1;
s = eem;
itera = 0;

while epsi > epsimin
  epsvecn = epsi*een;
  epsvecm = epsi*eem;
  ux1 = upp-x;
  xl1 = x-low;
  ux2 = ux1.*ux1;
  xl2 = xl1.*xl1;
  uxinv1 = een./ux1;
  xlinv1 = een./xl1;

  plam = p0 + P'*lam ;
  qlam = q0 + Q'*lam ;
  gvec = P*uxinv1 + Q*xlinv1;
  dpsidx = plam./ux2 - qlam./xl2 ;

  rex = dpsidx - xsi + eta;
  rey = c + d.*y - mu - lam;
  rez = a0 - zet - a'*lam;
  relam = gvec - a*z - y + s - b;
  rexsi = xsi.*(x-alfa) - epsvecn;
  reeta = eta.*(beta-x) - epsvecn;
  remu = mu.*y - epsvecm;
  rezet = zet*z - epsi;
  res = lam.*s - epsvecm;

  residu1 = [rex' rey' rez]';
  residu2 = [relam' rexsi' reeta' remu' rezet res']';
  residu = [residu1' residu2']';
  residunorm = sqrt(residu'*residu);
  residumax = max(abs(residu));

  ittt = 0;
  while residumax > 0.9*epsi & ittt < 100
    ittt=ittt + 1;
    itera=itera + 1;

    ux1 = upp-x;
    xl1 = x-low;
    ux2 = ux1.*ux1;
    xl2 = xl1.*xl1;
    ux3 = ux1.*ux2;
    xl3 = xl1.*xl2;
    uxinv1 = een./ux1;
    xlinv1 = een./xl1;
    uxinv2 = een./ux2;
    xlinv2 = een./xl2;
    plam = p0 + P'*lam ;
    qlam = q0 + Q'*lam ;
    gvec = P*uxinv1 + Q*xlinv1;
    GG = P*spdiags(uxinv2,0,n,n) - Q*spdiags(xlinv2,0,n,n);
    dpsidx = plam./ux2 - qlam./xl2 ;
    delx = dpsidx - epsvecn./(x-alfa) + epsvecn./(beta-x);
    dely = c + d.*y - lam - epsvecm./y;
    delz = a0 - a'*lam - epsi/z;
    dellam = gvec - a*z - y - b + epsvecm./lam;
    diagx = plam./ux3 + qlam./xl3;
    diagx = 2*diagx + xsi./(x-alfa) + eta./(beta-x);
    diagxinv = een./diagx;
    diagy = d + mu./y;
    diagyinv = eem./diagy;
    diaglam = s./lam;
    diaglamyi = diaglam+diagyinv;

    if m < n
      blam = dellam + dely./diagy - GG*(delx./diagx);
      bb = [blam' delz]';
      Alam = spdiags(diaglamyi,0,m,m) + GG*spdiags(diagxinv,0,n,n)*GG';
      AA = [Alam     a
            a'    -zet/z ];
      solut = AA\bb;
      dlam = solut(1:m);
      dz = solut(m+1);
      dx = -delx./diagx - (GG'*dlam)./diagx;
    else
      diaglamyiinv = eem./diaglamyi;
      dellamyi = dellam + dely./diagy;
      Axx = spdiags(diagx,0,n,n) + GG'*spdiags(diaglamyiinv,0,m,m)*GG;
      azz = zet/z + a'*(a./diaglamyi);
      axz = -GG'*(a./diaglamyi);
      bx = delx + GG'*(dellamyi./diaglamyi);
      bz  = delz - a'*(dellamyi./diaglamyi);
      AA = [Axx   axz
            axz'  azz ];
      bb = [-bx' -bz]';
      solut = AA\bb;
      dx  = solut(1:n);
      dz = solut(n+1);
      dlam = (GG*dx)./diaglamyi - dz*(a./diaglamyi) + dellamyi./diaglamyi;
    end