%Verion of gendata.m modified by Vero
%This is a matlab script that generates the input data


% the configuation approximately the ISOMIP experiment no. 1
% require matlab functions for equation of state


% Dimensions of grid
nx=30; 
ny=50;
nz=100;
delZ = 10;
delz=10;
dz=10;

hfacMin = 0.2;

dlat = 0.125/4; dy=dlat;
dlon = 0.125; dx=dlon;

%eos = 'linear';
eos = 'jmd95z';
% eos = 'mdjwf';

acc = 'real*8';

long = [-105.5:dlon:-99.375];
lonc = long+dlon/2;
latg = [-75.4457:dlat:-74.5068-dlat];
latc = latg+dlat/2;
size(latc)

% Nominal depth of model (meters)
H = -1000;					%water depth in the ice shelf cavity
Hmin = -900; % deepest point of cavern		
Hmax = -100; % shallowest point of cavern
dHdy = (Hmax-Hmin)/(max(latg)-min(latc));				%Slope of ice shelf: if denominator = nx, shelf will cover the whole domain

bathy = ones(nx,ny)*H;				%For flat bathymetry: bathy = ones(nx,ny)*H;
bathy(1,:) = 0;
bathy(nx,:) = 0; 
bathy(:,1) = 0;
%bathy(:,ny) = 0;
fid=fopen('bathymetry.pig.bin','w','b'); fwrite(fid,bathy,acc);fclose(fid);



dz = delZ*ones(1,nz);
zgp1 = [0,cumsum(dz)];
zc = .5*(zgp1(1:end-1)+zgp1(2:end));
zg = zgp1(1:end-1);
dz = diff(zgp1);
sprintf('delZ = %d * %7.6g,',nz,dz)


T_sfc = -1.9;
T_bottom = 1.1967;
del_T = (T_bottom - T_sfc)/((nz-1)*delZ);

for iz = 1:nz;
    tref(iz) = T_sfc + del_T*((iz-1)*delZ);    
end

S_sfc = 34.2050;
S_bottom = 34.6967;
del_S = (S_bottom - S_sfc)/((nz-1)*delZ);

for iz = 1:nz;
    sref(iz) = S_sfc + del_S*((iz-1)*delZ);    
end

% Gravity
gravity=9.81;
rhoConst = 1030;
% compute potential field underneath ice shelf
talpha = 2e-4;
sbeta  = 7.4e-4;
% tref = -1.9*ones(nz,1);
t    = tref;
% sref = 34.4*ones(nz,1);
s    = sref;
gravity = 9.81;
k=1;
dzm = abs([zg(1)-zc(1) .5*diff(zc)]);
dzp = abs([.5*diff(zc) zc(end)-zg(end)]);
p = abs(zc)*gravity*rhoConst*1e-4;
dp = p;
kp = 0;



while rms(dp) > 1e-13
  phiHydF(k) = 0;
  p0 = p;
  kp = kp+1
  for k = 1:nz
    switch eos
     case 'linear'
      drho = rhoConst*(1-talpha*(t(k)-tref(k))+sbeta*(s(k)-sref(k)))-rhoConst;
     case 'jmd95z'
      drho = densjmd95(s(k),t(k),p(k))-rhoConst;
     case 'mdjwf'
      drho = densmdjwf(s(k),t(k),p(k))-rhoConst;
     otherwise
      error(sprintf('unknown EOS: %s',eos))
    end
    phiHydC(k)   = phiHydF(k) + dzm(k)*gravity*drho/rhoConst;
    phiHydF(k+1) = phiHydC(k) + dzp(k)*gravity*drho/rhoConst;
  end
  switch eos
   case 'mdjwf'
    p = (gravity*rhoConst*abs(zc) + phiHydC*rhoConst)/gravity/rhoConst;
  end
  dp = p-p0;
end


%Modify icetopo (shape of ice shelf cavity)

% %icetopo = ones(ny,1)*min(Hmin + 2*dHdy*(lonc(nx)-long),Hmax); 
% B=min(Hmin + 2*dHdy*(lonc(ny)-long),Hmax);
% B=fliplr(B);
% 
% icetopo = ones(nx,1)*B; 
% %icetopo = icetopo';
% icetopo(:,101:end)=0;

% use streamice generated thickness
fid = fopen('h_init.box','r','b'); hinit=fread(fid,[dy dx],'real*8'); fclose(fid);
%hinit(:,1:5)=550;
icetopo = -917/1028*hinit;


%Modify icetopo (shape of ice shelf cavity)

icetopo = ones(ny,1)*min(Hmax,Hmin + 2*dHdy*(lonc(nx)-long)); icetopo = icetopo';
icetopo(1:25,:)=0;


% use streamice generated thickness
fid = fopen('h_init.box','r','b'); hinit=fread(fid,[30 50],'real*8'); fclose(fid);
%hinit(:,1:5)=550;
icetopo = -917/1028*hinit;


% adjust topo so that no hfac is smaller than hfacMin

for ix=1:nx
  for iy=1:ny
    k=max(find(abs(zg)<abs(icetopo(ix,iy))));
    
    if(~isempty(k))


    hfacTemp = (icetopo(ix,iy) - (-zg(k+1)))/delZ;
    
    if (hfacTemp < hfacMin)
        if (hfacTemp < hfacMin/2)
            hfacTemp = 0;
        else
            hfacTemp = hfacMin;
        end
    end
    
    else
        
        hfacTemp = 0;
        
    end
    
    icetopo(ix,iy) = icetopo(ix,iy) + hfacTemp;
    
  end
end

% phi anomaly (relative to hydrostatic with rho_const) at icetopo

% phi anomaly (relative to hydrostatic with rho_const) at icetopo

phi0surf = zeros(nx,ny);

for ix=1:nx
  for iy=1:ny
    k=max(find(abs(zg)<abs(icetopo(ix,iy))));
    if isempty(k)
      k=0;
    end
    if k>0
      
      dr = -zg(k) - icetopo(ix,iy);
      
      if (dr>=delZ/2)
          phi0surf(ix,iy) = phiHydF(k) + (delZ-dr) * (phiHydC(k)-phiHydF(k))/(delZ/2);
      else
          phi0surf(ix,iy) = phiHydC(k) + (delZ/2-dr) * (phiHydF(k+1)-phiHydC(k))/(delZ/2);
      end
      
    end
  end
end

mass = phi0surf / gravity - rhoConst * icetopo;

%use streamicegenerated thickness

%mass = hinit * 917;

fid = fopen('shelftopo.pig.bin','w','b'); fwrite(fid,icetopo,'real*8'); fclose(fid);
fid = fopen('shelficemassinit.bin','w','b'); fwrite(fid,mass,'real*8'); fclose(fid);
fid = fopen('pload.pig.jmd95z','w','b'); fwrite(fid,phi0surf,'real*8'); fclose(fid);

etainit = zeros(size(phi0surf));

% new topography: icetopo rounded to the nearest k * deltaZ
%                 eta_init set to make difference

icetopo2 = icetopo;

for ix=1:nx
  for iy=1:ny
    k=max(find(abs(zg)<abs(icetopo2(ix,iy))));
    if isempty(k)
      k=0;
    else
      
      dr = 1-(-zg(k) - icetopo2(ix,iy))/delz;
      if (dr > .5)
          % bring Ro_surf *up* to closest grid face & make etainit negative
          % to compensate
          icetopo2(ix,iy) = -zg(k);
          etainit(ix,iy) = (dr-1)*delz;
      else
          % bring Ro_surf *down* to closest grid face & make etainit pos
          % to compensate
          icetopo2(ix,iy) = -zg(k+1);
          etainit(ix,iy) = (dr)*delz;
      end
       
    end
  end
end

fid = fopen('shelftopo.round.bin','w','b'); fwrite(fid,icetopo2,'real*8'); fclose(fid);
fid = fopen('etainit.round.bin','w','b'); fwrite(fid,etainit,'real*8'); fclose(fid);