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INITIAL POSITIONS OF DIFFUSIVE PARTICLES

## A function takes in the number of diffusive particle
## as an argument and gets the initial positions in 2D
## as an outcome by inserting them in a square.
function p=initial_positions7(Nwalkers)
dt=3; ## to extend the interval of axes.
a=sqrt(Nwalkers); ## step size.
n=(a-1)/2; ## max range in the x and y axes.
if(rem(a,2)~=1) ## Nwalkers must be odd squared.
printf("The number you have entered is not an odd squared. Exiting...\n");
return
endif
n=(a-1)/2; ## max range in the x and y axes.
x=[-n:n]'; ## integer interval in the x axis.
p=zeros(a,2); ## initialize the positions of 'a' walkers.
p(:,1)=x; ## equate the column of p to x vector.
p=repmat(p,a,1); ## replicate positions of 'a' walkers to get a*a walkers.
for i=1:a:Nwalkers ## the loop through the number walkers.
m=(i+a-1)/a; ## index get the entries of x resp.
p(i:i+a-1,2)=x(m) ; ## y components are a-fold degenerate.
endfor
plot(p(:,1),p(:,2),'b*;;')
axis(dt*[-n, n,-n,n])
endfunction

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NEWTON-RAPSON METHOD FOR HEAT FLOW

##Constants and initializations
a=5.67E-8; ## Stefan-Boltzman constant[Watt/meter^2Kelvin^4]
e=0.8; ## Rod surface emissivity [Dimensionless]
h=20; ## Heat transfer coefficient of air flow [W/m^2-K]
Tinf=Ts=25; ## Temperature of air and the walls of the close[Celcius]
D=0.1; ## Diameter of the rod[meter]
I2R=100; ## Electric power dissipated in rod (Ohmic Heat)[W]
T=[]; ## Temperature of the rod[*C]
T(1)=25; ## Initial guess of the temperature of the rod[*C]
Q=[]; ## Heat function [W]
Qp=[]; ## First derivative of Q wrt T [W/C*].
for i=1:100
Q(i)=pi*D*(h*(T(i)-Tinf)+e*a*(T(i)^4-Ts^4))-I2R;
Qp(i)=pi*D*(h+4*e*a*T(i)^3);
T(i+1)=T(i)-Q(i)/Qp(i); ## Newton-Rapson Method
endfor
printf('The steady state temperature is %f\n',T(i+1))
save -text HeatFlowTemp.dat
## The plot
t=1:100; ##temperature
for n=1:100
H(n)=pi*D*(h*(t(n)-Tinf)+e*a*(t(n)^4-Ts^4))-I2R;
endfor
plot(t,H)
xlabel('T(Celcius)');
ylabel('Q(Watt)');
legend('Q(T)');
title('Heat flow vs Temperatu…