function [ch,chda,chdb,chdc]=fitting_val(a0,b0,c0)
E = 1; m = 0.33;
p = E / ( (1+m) * (1-2*m) );
D = [p*(1-m) p*m     p*m     0         0         0
    p*m      p*(1-m) p*m     0         0         0
    p*m      p*m     p*(1-m) 0         0         0
    0        0       0       p*(0.5-m) 0         0
    0        0       0       0         p*(0.5-m) 0
    0        0       0       0         0         p*(0.5-m)];
y0=[D(1,1),D(1,2),D(1,3),D(2,2),D(2,3),D(3,3),D(4,4),D(5,5),D(6,6)];

ch0=zeros([9,size(a0)]);
chda0=zeros([9,size(a0)]);
chdb0=zeros([9,size(a0)]);
chdc0=zeros([9,size(a0)]);

load('FittingParam.mat', 'paramFitting')
for i=1:9
    b_reg = paramFitting(:,i);
    [y,da,db,dc]=derivativeFromFitting(a0,b0,c0,b_reg);
    ch0(i,:,:,:)=y.*(1+a0+b0+c0>0)+y0(i).*(1+a0+b0+c0<=0);
    ch0(i,:,:,:)=max(ch0(i,:,:,:),y0(i)*1e-9);
    chda0(i,:,:,:)=da.*(1+a0+b0+c0>0);
    chdb0(i,:,:,:)=db.*(1+a0+b0+c0>0);
    chdc0(i,:,:,:)=dc.*(1+a0+b0+c0>0);
end

ch=zeros([12,size(a0)]);
chda=zeros([12,size(a0)]);
chdb=zeros([12,size(a0)]);
chdc=zeros([12,size(a0)]);
idx = [1,2,3, 2,4,5, 3,5,6, 7,8,9];
for i=1:12
    ch(i,:,:,:)=ch0(idx(i),:,:,:);
    chda(i,:,:,:)=chda0(idx(i),:,:,:);
    chdb(i,:,:,:)=chdb0(idx(i),:,:,:);
    chdc(i,:,:,:)=chdc0(idx(i),:,:,:);
end

end