How to use a loop to add a value at an increasing interval

Hi, I am trying to calculate the cost of a range of values where there is a linear cost per each unit and a separate cost per 100 units. The linear cost per unit is simple but I am trying to use a range that updates per each iteration by incorporating this into a while loop and an IF statement. I could really use some advice as I keep running into problems. There is an example of the code I am using below.

%
costpu = 320; % cost per unit
costsy = 20000; % cost per 100 units
units = linspace(100,4000,36); % row vector of units
n = 0;
m = 100; % m and n are the starting range
p = 1;
idx = 1;
while n < units(end)
if units(idx) > n & units(idx) < m
cost(idx) = (units(idx)*costpu) + (costsy*p)
end
n = n + 100;
m = m + 100; % increasing the range per each iteration
p = p + 1; % 
idx = idx + 1;
end

If any one has some advice or an alternative approach to this problem I would really appreciate it.

Thanks.

[Jan]

I do not understand the question. What exactly does "use a range that updates per each iteration by incorporating this into a while loop and an IF statement" mean? What did you try an in which troubles did you run?

Answer 1

[Robert]

If I gather correctly what you are trying to do, you don't need the loop at all. You can determine the total cost for any number of units as shown below.

costpu = 320; % cost per unit
costsy = 20000; % cost per 100 units
units = linspace(100,4000,36); % row vector of units

cost = costpu*mod(units,100) + costsy*floor(units/100);

plot(units,cost)

Note that mod returns the number of units that don't make an even hundred and floor gives you the number of sets of 100.

[Thomas]

Ah! Thank you very much. That has helped a great deal.