How to make mt_rand more random? PHP

[Lumi]

I have a site that I use mt_rand for a button to pick a random video but it doesn't seem all that random.

 

It will pick sometimes the same video 2 times in a row when there's over 70 on the site.

 

Also if anyone has a JavaScript alternative let me know.

[coen113]

I have a site that I use mt_rand for a button to pick a random video but it doesn't seem all that random.

 

It will pick sometimes the same video 2 times in a row when there's over 70 on the site.

 

Also if anyone has a JavaScript alternative let me know.

just because it picks 2 times thesame vid in a row doesnt mean that its not random. if you throw a dice twice, odds are, it will be thesame number. same goes for that.

[Lumi]

just because it picks 2 times thesame vid in a row doesnt mean that its not random. if you throw a dice twice, odds are, it will be thesame number. same goes for that.

yes but picking a number 1-70+ 2 times in a row doesn't happen often with items like dice. 

[coen113]

yes but picking a number 1-70+ 2 times in a row doesn't happen often with items like dice. 

but it can happen.

im afraid i cant help you any further, i dont know any php.

[fizzlesticks]

Keep a list of the last few videos it requested then keep picking a random video until you get one not in that list (or subtract those videos from the full set and just pick 1).

[RatedBlam]

yes but picking a number 1-70+ 2 times in a row doesn't happen often with items like dice.

If I remember my math's correctly, every time eg. You throw a die you have 1/6 chance to get a number so getting 1+2 is just as possible as getting 1+1

[Lumi]

If I remember my math's correctly, every time eg. You throw a die you have 1/6 chance to get a number so getting 1+2 is just as possible as getting 1+1

Yeah on a 6 sided dice not a 70+ sided one.

[RatedBlam]

Yeah on a 6 sided dice not a 70+ sided one.

I think if the die was 70+ the chances would still be equal, that is if I have my maths right

[WanderingFool]

I have a site that I use mt_rand for a button to pick a random video but it doesn't seem all that random.

 

It will pick sometimes the same video 2 times in a row when there's over 70 on the site.

 

Also if anyone has a JavaScript alternative let me know.

 

By the looks of things mt_rand should be quite random (that is assuming you are using mt_rand(min, max), even if you aren't it is still adequately random).  The mt_rand based on the documentations I read use the Mersenne twister primes (http://en.wikipedia.org/wiki/Mersenne_twister).%C2'> The MT is fairly standard random number generator

 

Anyways just to clarify a few things...there is a 1 in 70 chance of repeating a video in a row.

1/70 * 1 / 70 * 70 = roughly 1.4% chance. 

With that said if you test it over 10 new random video views, that is 1 - (69/70)^10 = 13.4% of the time you will get a video that repeats itself.

 

A possible solution would just keep track with a cookie the last 3 or 4 videos and make sure the random doesn't choose them...