Random PBP

[strujnimen]

I need code to generate random number from 1 to 7 in PICBASIC PRO. How to? Thanks.

[ScaleRobotics]

Might not be the best way, but here is one way (untested):

random_word var word
randomdig var byte

generate_random:
   Random random_word               'generate random number and put into random_word var
   randomdig = random_word DIG 1 'read only first digit
   if randomdig = 8 then goto generate_random 'if its 8 then do over
   if randomdig = 0 then goto generate_random ' if its 0 then do over

[ScaleRobotics]

Oh yeah, and filter out 9 as well.

[RussMartin]

To filter, you can also use:

if randomdig > 7 or randomdig < 1 . . .

Russ

[Darrel Taylor]

I need code to generate random number from 1 to 7 in PICBASIC PRO. How to? Thanks.

PBP's RANDOM command is FAR from RANDOM.
Makes good pink noise though ...

But anywho ...

    RANDOM   RandVar
    Result = RandVar ** 7 + 1

[RussMartin]

PBP's RANDOM command is FAR from RANDOM.

Just how far from "random" is it?

[Darrel Taylor]

Just how far from "random" is it?

Pretty FAR!

It's a REPEATING sequence of 65535 numbers.

If you start with the same "Seed" each time ...
You will get the exact same numbers every time you run your program.

If you start with a different seed, all that does it put you somewhere in the middle of that same repeating sequence.

There's really nothing "RANDOM" about it.
It's called pseudo-random, but even that's a stretch.
<br>

[boroko]

OK.....

What is the best way to approach the need for the appearance of "random"?

I have seen that there is a pattern and haven't figured out a way to circumvent it other than to make the sequence long to make it harder to see the pattern (LEDs)
Mark

[Michael]

PBP's RANDOM command is FAR from RANDOM.
Makes good pink noise though ...

But anywho ...

    RANDOM   RandVar
    Result = RandVar ** 7 + 1

This is an older post I searched because I need to generate a random number and saw you can do it with a word variable. Like this fella, I need a smaller number.

I'm having a hard time grasping what is going on with Result = ** 7 + 1
Huh ?

Saw --
** Returns the high 16 bits of a 16-bit multiply result

But even that isn't making sense to me.

Has there been any updates to random where you can apply it to more than a word? -thanks

[HenrikOlsson]

That line of code will scale the WORD sized Randvar variable (0 to 65535) to a value ranging from 1 to 7.

Bascially it's the same as doing Result = Randvar * 7 / 65536 + 1

/Henrik.

[CuriousOne]

Use biased zener connected to ADC and sample the input