Matlab code to find all prime numbers between 2 and 5000

Discussion in 'Programmer's Corner' started by Dapnc, Feb 7, 2013.

  1. Dapnc

    Thread Starter New Member

    Feb 7, 2013
    3
    0
    Need to write a matlab program that will find all prime numbers between 2 and 5000 but I can't use any built in matlab functions. Please help. It also has to run quickly.
     
  2. tshuck

    Well-Known Member

    Oct 18, 2012
    3,531
    675
    There are plenty of algorithms out there, what prevents you from using one of those? Or, are you wanting us to write the MATLAB code for you?

    How quickly is quickly?
     
  3. Dapnc

    Thread Starter New Member

    Feb 7, 2013
    3
    0
    Having trouble not using matlab built-in functions. Just need help getting started.
     
  4. tshuck

    Well-Known Member

    Oct 18, 2012
    3,531
    675
  5. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    num = prime(5000)

    Using that internal function, write the rest of the program, such as desired output format, optional input value for number (just like the built in function).

    Once that is complete, Write a prime number algorithm. Run both prime(5000) and yourfunc(5000) to compare time to run, (remember to compile for max speed if you didn't know that). Once you get an algorithm that is close or less than the builtin function AND produces the same results, you are done.

    That, combined with the algorithm link above should be all you need to get you started conceptually.
     
  6. vortmax

    Member

    Oct 10, 2012
    103
    18
    another good trick with matlab: many builtin functions are written in m-code, so you can see how they work by running `edit <fcn>`. However, the low level functions tend to be written in C, and so you can't see how they do their magic.
     
  7. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    Download a list of primes <=5000 from the internet, then install it in Matlab as a lookup table.

    That is very easy to get a finished result and will really "run quickly".
     
    djsfantasi, jaygatsby and thatoneguy like this.
  8. tgstanfi

    New Member

    Feb 22, 2013
    1
    0
    Hi! I am having to do this same project and I was just wondering if you ever figured out a code that worked? I have been working on it for hours now and I started one but it ran forever and isn't right. I would greatly appreciate it!
     
  9. tshuck

    Well-Known Member

    Oct 18, 2012
    3,531
    675
    This site is not meant for sharing homework answers, it is, however, for educational purposes. If you'd like to start your own thread and post what you came up with, we'd be glad to take a look at it for you...
     
  10. TinkersALot

    New Member

    Jan 8, 2013
    2
    0
Loading...