How to shuffle the values in a vector array ?

Steve · **Joined:** Dec 26, 2014 **Posts:** 205

#( 0 0 0 0 1 1 1 1 2 2 2 2 )

I’ve created this small test vector array in the SFC and filled it with an equal number of zero’s, one’s and two’s, these are to be used as conditional flags in a script

What I need to do next is shuffle them into a random order, but I can’t work out how to do it, any advice would be appreciated

Thanks for looking

trandoductin · **Posted:** Mon Jun 01, 2015 11:52 am **(#2)**

this is probably a total hack but you could do something like this

Code: Select all

(define v #( 0 0 0 0 1 1 1 1 2 2 2 2 ))
(srand (car (gettimeofday)))
(define a 0)
(define b 0)
(define temp 0)
(define swaps 12) ; number of random swaps
(while (> swaps 0)
    (set! a (rand (vector-length v)))
    (set! b (rand (vector-length v)))
    (set! temp (aref v a))
    (aset v a (aref v b))
    (aset v b temp)
    (set! swaps (- swaps 1))
)

Steve · **Joined:** Dec 26, 2014 **Posts:** 205

trandoductin wrote:

this is probably a total hack but you could do something like this

Code: Select all

(define v #( 0 0 0 0 1 1 1 1 2 2 2 2 ))
(srand (car (gettimeofday)))
(define a 0)
(define b 0)
(define temp 0)
(define swaps 12) ; number of random swaps
(while (> swaps 0)
    (set! a (rand (vector-length v)))
    (set! b (rand (vector-length v)))
    (set! temp (aref v a))
    (aset v a (aref v b))
    (aset v b temp)
    (set! swaps (- swaps 1))
)

Thanks for the quick reply, it looks interesting. I need to spend some time now analysing the script to follow the logic and then hope to adapt it to run in my script.

Thanks again

Steve

Steve · **Joined:** Dec 26, 2014 **Posts:** 205

trandoductin wrote:

this is probably a total hack but you could do something like this

Code: Select all

(define v #( 0 0 0 0 1 1 1 1 2 2 2 2 ))
(srand (car (gettimeofday)))
(define a 0)
(define b 0)
(define temp 0)
(define swaps 12) ; number of random swaps
(while (> swaps 0)
    (set! a (rand (vector-length v)))
    (set! b (rand (vector-length v)))
    (set! temp (aref v a))
    (aset v a (aref v b))
    (aset v b temp)
    (set! swaps (- swaps 1))
)

I see how it works by swapping the values of two randomly chosen cells, and I take it, referring to it being a total hack is that there is no guarantee all locations are changed, but this might actually work in my favour so I made the variable (swaps) a value to be input. The only changes I made was aset/aref to vector-set/ref

My original script generated a sloped image that produced a bad join when polar coordinates were used

Your hack aids in generating a level image (image 2)

Which gives a good join when polar coordinates are used (image 3)

Thanks again, it would have taken me a long time to work that code out myself if ever

Attachment:

1.jpg [ 26.03 KiB | Viewed 2746 times ]

Attachment:

File comment: image 2

2.jpg [ 105.47 KiB | Viewed 2746 times ]

Attachment:

File comment: image 3

3.jpg [ 91.94 KiB | Viewed 2746 times ]

trandoductin · **Posted:** Tue Jun 02, 2015 9:33 am **(#5)**

glad it helped.
Those are some ultra cool images btw.