Question

matlab stuff.

Answer 1

@Nnesha I'll grab the code in a bit... I need to get it first :P

Answer 2

hmm would it be better to post in computer science?

Answer 3

what D:!

Answer 4

?/???///

Answer 5

no. matlab has the word has the word math in it :P

Answer 6

hmmm

Answer 7

yessssssssss....moving on...

Answer 8

matlab related to computers http://openstudy.com/study#/groups/Computer%20Science

Answer 9

It has something to do with a ricker model ugh... anyway I got the first two codes to work, but when I tried the example for the third code the ditera2, I have an error on line 9

Answer 10

i dotn have matlab

Answer 11

@dan815 is here! THANK GAWD! I need help on this particular code!

Answer 12

@dan815
matlabsessioncodes is the example
drickerz is the two codes that I already have for the previous two examples.
The third one in matlabsessioncodes is driving me nuts because it produces an error line 9 and I've typed it correctly ... even copypasta'd and still won't work. I have no idea what is going on

Answer 13

matlab is short for matrix laboratory, not math laboratory

Answer 14

sorry but I still have no idea why the example code (the ditera2) isn't working right. I have an error line 9 issue

Answer 15

Aha, math lab.

Answer 16

in drickerz, you appear to be calling the function `dricker`, inside of itself, which sets up an infinite loop

Answer 17

huh?

Answer 18

infinite loop?

Answer 19

well the exercise said to change it to dricker for that equation

Answer 20

function [f, fprime] = dricker(x,b)
f=b.*x.*exp(-x);
if nargout>1
fprime =-b.*x.*exp(-x)+b.*exp(-x);
end
should be it for the first one right?

Answer 21

@Kainui we're stuck in code matlab land >_<

Answer 22

if I don't have that ; at each line, then the result just won't show up

Answer 23

% Computes iterates and stores data for cobweb plot

function [x,web1,web2]=diter2(x0,r,n)
%DITER2 Computes iterates of the discrete logistic function
%
x=zeros(n+1,1);
web1=zeros(202,1); web2=zeros(202,1);
x(1,1)=x0;
j=1;
for i=1:n
xi=x(i,1);
if i>=n-100
web1(j)=x(i-1,1); web2(j)=x(i,1);
web1(j+1)=x(i,1); web2(j+1)=x(i,1);
j=j+2;
end
x(i+1,1)=dlogistic(xi,r);
end

is driving me nuts. Why isn't that part of the code working?

Answer 24

when `i=1`, `i-1` = 0, so `x(i-1, 1)` is x(0, 1)

matlab starts indexing from one, not zero, so x(0,1) is undefined

Answer 25

so i = 2 for this to work?

Answer 26

ahahahaah I made i=2 and it worked so let's see
i = 2
2-1 =1
x(i-1,1) is x(1,1) @UnkleRhaukus

Answer 27

year

Answer 28

eww my graph looks flat!

Answer 29

what is it meant to look like?

Answer 30

I'm not sure.. the example says
% Computes iterates and stores data for cobweb plot

function [x,web1,web2]=diter2(x0,r,n)
%DITER2 Computes iterates of the discrete logistic function
%
x=zeros(n+1,1);
web1=zeros(202,1); web2=zeros(202,1);
x(1,1)=x0;
j=1;
for i=1:n
xi=x(i,1);
if i>=n-100
web1(j)=x(i-1,1); web2(j)=x(i,1);
web1(j+1)=x(i,1); web2(j+1)=x(i,1);
j=j+2;
end
x(i+1,1)=dlogistic(xi,r);
end

but I wasn't given a picture

Answer 31

moreover why the heck am I given 2 graphs on the fourth example?

Answer 32

I got this to work. That code and a dlogplt code should be in unison ....and I misunderstood the tutorial page, but yeahhh!

Answer 33

@ganeshie8 look at my diagrams!