I have a question regarding time dependent loop, as I want to have a variable changing with time in the loop from 0 to 30

gamma(t) =4-(6/90*t);

Answer 1

[Ameer Hamza]

Without loop:

t = linspace(0,30,100); % create 100 points between 0 and 30
gamma = 4-(6/90*t); 

Using for loop:

t = linspace(0,30,100);
gamma = zeros(size(t));
for i=1:numel(t)
    gamma(i) = 4-(6/90*t(i));
end

[Fae ba]

thanks for your hint,but if I want to compare 3 cases of gamma (gamma(I),gamma(J) and gamma(k)) would it be the same?

[Ameer Hamza]

Gamma is a 1D vector? How do you want to compare its elements?

[Fae ba]

I want to define three cases of constant, linear increasing and linear decreasing for gamma changes with time for e.g: gamma(t)=4,

gamma(t)= 5+0.7(t),

gamma(t)=5-0.7(t).

[Ameer Hamza]

Like this?

t = linspace(0,30,100); % create 100 points between 0 and 30
gamma1 = 4*ones(size(t)); 
gamma2 = 5+0.7*t; 
gamma3 = 4-0.7*t; 
plot(t,gamma1,t,gamma2,t,gamma3);

[Fae ba]

As I want the gamma to be time varying is it correct to use the following code?

t = linspace (0,30);
gammaA = zeros (size (t));
gammaB = zeros (size (t));
gammaC = zeros (size (t));
for i = 0: numel (t)
    gammaA (i) = 4;
end
for j = 0: numel (t)
    gammaB (j) = 5+ (0.7 * t (j));
end
plot (gammaB)
for k = 0: numel (t)
    gammaC (k) = 5- (0.7 * t (k));
end

[Ameer Hamza]

The logic is correct. There are some syntax errors. In MATLAB, the index starts from 1. Also, if you want to plot all lines, you need to hold the axes

t = linspace (0,30);
gammaA = zeros (size (t));
gammaB = zeros (size (t));
gammaC = zeros (size (t));
axes();
hold on
for i = 1: numel (t) % <--- start from 1
    gammaA (i) = 4;
end
plot (gammaA)
for j = 1: numel (t) % <--- start from 1
    gammaB (j) = 5+ (0.7 * t (j));
end
plot (gammaB)
for k = 1: numel (t) % <--- start from 1
    gammaC (k) = 5- (0.7 * t (k));
end
plot (gammaC)

[Fae ba]

thanks it works!!!

[Ameer Hamza]

Glad to be of help.

[Fae ba]

I want to develope the code to the case where the gamma is changes in every loop iteration by assuming that x is changing between 0 and 5, then how can I plot (x, c1) wrt to three cases of gamma for a fixed point eg t = 5? I define f (t) and v1, v2 and c1 just for the first case, is there any way to define the same for the two other case where there are gammaB and gammaC with the same formula? this is the primary code:

r = 0.02;

mu = 0.08;

sigma = 0.2;

T = 30;

rho = 0.02;

for x = 0: 1: 5

t = 5;

gammaA (i) = 4;

gammaB (j) = 5+ (0.07 * t (j));

gammaC (k) = 5- (0.07 * t (k));

for i = 0:30

f1 = (exp (-rho * t) / gammaA (i)) * exp (((1-gammaA (i)) / gammaA (i)) * (r + (mu - r) ^ 2 / (2 * sigma ^ 2 * gammaA (i))) * (T - t));

v1 = (f1. ^ gammaA (i)). * (x. ^ - gammaA (i));

C1 = exp (-rho * t / gammaA (i)) * (v1. ^ (-1 / gammaA (i)));

end

for j = 0:30

f2 = (exp (-rho * t) / gammaB (j)) * exp (((1-gammaB (j)) / gammaB (j)) * (r + (mu - r) ^ 2 / (2 * sigma ^ 2 * gammaB (j))) * (T - t));

v2 = (f2 ^ gammaB (j)) * (x. ^ - gammaB (j));

C2 = exp (-rho * t / gammaB (j)) * (v2. ^ (-1 / gammaB (j)));

end

for k = 0:30

f3 = (exp (-rho * t) / gammaC (k)) * exp (((1-gammaC (k)) / gammaC (k)) * (r + (mu - r) ^ 2 / (2 * sigma ^ 2 * gammaC (k))) * (T - t));

v3 = (f3 ^ gammaC (k)) * (x. ^ - gammaC (k));

C3 = exp (-rho * t / gammaC (k)) * (v3. ^ (- 1 / gammaC (k)));

end

set (0, 'DefaultAxesColorOrder', [0 0 0], 'DefaultAxesLineStyleOrder', '- | -. | -')

hold on

plot (x, c1, x, c2, x, c3)

legend ('gammaA', 'gammaB', 'gammaC')

hold off

[Ameer Hamza]

The question is confusing. Can you clarify it?