Plot and interp using Spline method

I'm trying to correct this line ploting using interpolate method .

but seem blocky shape appears

the coding in the body

function [TI1,TI2,TI3] = ER_Function 
er1=(1+1.8*10^14*1i); 
er2=(2.5+2.5*10^-3*1i);
Hc=(10^6);
H1=(0); 
P1= 0:0.02:0.30;
Pc=(0.33).*exp((-(H1)/Hc));
c1=(1-3*Pc).*(((P1)./(Pc)).^Pc).*(((1-P1)./(1-Pc)).^(1-Pc)); 
T1=(1./(2.*(2+c1))).*(((3*P1-1+c1)*er1+(2-3.*P1-c1)*er2)+(((((3*P1-1+c1)*er1+(2-3.*P1)*er2).^2)+(4.*(er1).*(er2).*(1-c1).*(2+c1))).^0.5)); 
PI1=[0,0.20,0.23,0.25,0.27,0.30];
TI1= spline (P1,T1,PI1);
P2= 0:0.02:0.30; 
er1=(1+1.8*10^14*1i);
er2=(2.5+2.5*10^-3*1i); 
Hc=(10^6);
H2=(10^6);
Pc=(0.33).*exp((-(H2)/Hc));
c2=(1-3*Pc).*(((P2)./(Pc)).^Pc).*(((1-P2)./(1-Pc)).^(1-Pc)); 
T2=(1./(2.*(2+c2))).*(((3*P2-1+c2)*er1+(2-3.*P2-c2)*er2)+(((((3*P2-1+c2)*er1+(2-3.*P2)*er2).^2)+(4.*(er1).*(er2).*(1-c2).*(2+c2))).^0.5)); 
PI2=[0,0.20,0.23,0.25,0.27,0.30];
TI2= spline (P2,T2,PI2);
P3= 0:0.02:0.30;
er1=(1+1.8*10^14*1i); 
er2=(2.5+2.5*10^-3*1i);
Hc=(10^6);
H3=(2*10^6);
Pc=(0.33)*(exp(-H3/Hc));
c3=(1-3*Pc).*(((P3)./(Pc)).^Pc).*(((1-P3)./(1-Pc)).^(1-Pc)); 
T3=(1./(2.*(2+c3))).*(((3*P3-1+c3)*er1+(2-3.*P3-c3)*er2)+(((((3*P3-1+c3)*er1+(2-3.*P3)*er2).^2)+(4.*(er1).*(er2).*(1-c3).*(2+c3))).^0.5)); 
PI3=[0,0.20,0.23,0.25,0.27,0.30];
TI3= spline (P3,T3,PI3);
J=plot ( PI1, real(TI1),'r',PI2, real (TI2),'g',PI3, real (TI3) , 'b');
J(1).LineWidth = 2;
J(2).LineWidth = 2;
J(3).LineWidth = 2;
title('Magnetic Field' ),xlabel('(P) concentration Volume'),ylabel('\bf\epsilon^e','FontSize',20)
legend({'H1=0','H2=10^6','H3= 2*10^6'},'Location','northwest','NumColumns',3)
end

[darova]

What is the problem?

[Ammar Ahmed]

lines are not smooth ,even when i used the interpolating method .

How I could make the lines smoother?Is there Specific command?

Answer 1

[the cyclist]

It's presumably because you have not chosen your query points to be very close together. Do you get something closer to what you expect if you define something like

PI3=[0:0.002:0.30];