how to use array indices in not logical form

Hi

I am working on a project and I have the equation below and when I use for loops because my T is a float Number something like 0.15 I get an error that I should use positive or logical numbers how sholud I fix that ??

thank you

[KSSV]

Show us your code. Copy and paste the code here.

[arash rad]

%-- Extract some data

arrival=xlsread('tripinfo.xlsx','G:G');
depart_time=xlsread('tripinfo.xlsx','B:B');
speed_m = xlsread('loop.xlsx','G:G');
N_veh = xlsread('loop.xlsx','J:J');
Nt = length(speed_m)/2;
speed = zeros(Nt,1);
vehicle_number = zeros(Nt,1);
qu = zeros(Nt,1);
%-- Here we calculate number of vehicles that we need for calcualtion
%parameters
for k = 1:Nt;
    
    speed(k,1) = [speed_m((2*k)-1) + speed_m(2*k)]/2;
    vehicle_number(k,1) = [N_veh((2*k)-1) + N_veh(2*k)];
    qu(k,:) = vehicle_number(k,1);
    
    
    
end
speed;  
vehicle_number;
qu = qu';
%-- first we want to extract data from sumo in every 10 minutes.in step one
%we want to calculate how many cars are in the intersection in specific
%intersection

figure;
bar(qu)
title("Upstream Flow")

%% calculate parametrs
delta_x = 500 - 70 ;
T = zeros(Nt,1);

for i =1:length(qu)
    tm(i,:) = ((1/qu(i))*(delta_x/speed(i)));
    T(i) = delta_x/(speed(i)); %lag time 
end
tm ;
beta = 0.8;
alpha = 0.5;

ta = beta*tm; %lag time 
Ftu_den = 1+(alpha*ta);
Ftu = 1./Ftu_den;

%% Arriving flow distribution
qd = zeros(Nt,1);


for j =ta:ta+length(qu))
    qd(:,j) = ((((1-Ftu).^(j-ta(j)))).*Ftu)*qu(j)
end 

[Walter Roberson]

    tm(i,:) = ((1/qu(i))*(delta_x/speed(i)));

tm is a vector or perhaps a 2D array. Not scalar.

beta = 0.8;
alpha = 0.5;
ta = beta*tm; %lag time 

ta is a constant multiple times tm, and tm is non-scalar so ta is non-scalar.

for j =ta:ta+length(qu))

What does it mean to have a for loop whose lower bound is an array ?

    qd(:,j) = ((((1-Ftu).^(j-ta(j)))).*Ftu)*qu(j)

Suppose the for loop somehow managed to assign the full array ta to j . Then you use ta(j) so you would be indexing ta at the values of ta . Are you sure that is wise?

Answer 1

[Walter Roberson]

syms F_cyc_k i q_up T t 
assume(0 < F_cyc_k & F_cyc_k < 1)
assume(T > 0)

q_down = symsum( ((1-F_cyc_k)^(i-T) * F_cyc_k)*q_up*(t-i), i, T, inf)

q_down = 

The limit would be different if might be outside the range 0 to 1 exclusive, or if T might be negative.