problem with getting for loop to work

function int=calculateintegral(from,to,subinterval)
inttemp=0;
if rem(subinterval,2)>0
    int='subinterval must be devidable on two'
else
for x=from+subinterval:subinterval*2:to-subinterval
   y1=4*exp(-(x)^2)
   y2=2*exp(-(x+((to-from)/subinterval))^2)
   inttemp=inttemp+y1+y2
end
end
int=inttemp

when i ran it in matlab it does not seem to loop through the for-loop or the if-condition:

>> calculateintegral(0,1,1000)

int =

     0

ans =

     0

>> calculateintegral(0,1,1001)

int =

     0

ans =

     0

Answer 1

[Fangjun Jiang]

Use your input argument, your for-loop looks like this:

for x=1000:2000:-999

No loop is executed at all.

I don't think your subinterval is defined correctly. Running calculateintegral(0,100,2) seems to give you some results.