Re: [RNG] Generating for enums

[Gary Gregory]

Yeah, sorry, I forgot about the hard coded enuf.

Gary

On Aug 5, 2017 11:37 AM, "Gilles"  wrote:

> On Sat, 5 Aug 2017 09:47:20 -0700, Gary Gregory wrote:
>
>> On Fri, Aug 4, 2017 at 1:59 PM, Gilles 
>> wrote:
>>
>> Hi Gary.
>>>
>>> On Fri, 4 Aug 2017 11:10:57 -0700, Gary Gregory wrote:
>>>
>>> For example, I have a enum like:

 public enum CardinalDirection (NORTH,SOUTH,EAST,WEST)

 and I want to say

 traveler.travel(nextRandomDirection());

 where

 public CardinalDirection nextRandomDirection() {
return rng.next(CardinalDirection.class);
 }


>>> Actually, "Commons RNG" already provides all the necessary functionality
>>> for a one-liner:
>>>
>>> ---CUT---
>>> import java.util.Arrays;
>>> import org.apache.commons.rng.simple.RandomSource;
>>> import org.apache.commons.rng.sampling.CollectionSampler;
>>>
>>> CollectionSampler r
>>> = new CollectionSampler<>(RandomSource.create(RandomSource.SPLIT_
>>> MIX_64),
>>>   Arrays.asList(CardinalDirectio
>>> n.values()));
>>>
>>> CardinalDirection e = r.sample();
>>> ---CUT---
>>>
>>>
>> Very nice, thank you.
>>
>> I can see a wrapper for this boilerplate though:
>>
>> public class RandomEnum {
>>
>> private final Class enumClass;
>> private final CollectionSampler rng;
>>
>> public RandomEnum(final Class enumClass) {
>> super();
>> this.enumClass = enumClass;
>> this.rng = new
>> CollectionSampler<>(RandomSource.create(RandomSource.SPLIT_MIX_64),
>> Arrays.asList(CellDirection.values()));
>>
>> }
>>
>> public CellDirection next() {
>> return rng.sample();
>> }
>>
>> @Override
>> public String toString() {
>> return "RandomEnum [rng=" + rng + ", enumClass=" + enumClass + "]";
>> }
>> }
>>
>
> I guess there is a mix of generics and "specifics" here (cf.
> "CellDirection"). And if you have only have a generic "E" in
> that class, you won't be able to call "E.values()".
> Then see also my other post:
>   http://markmail.org/message/h63yb7ozk4nyjagj
>
> However, what does one gain with having to call this one-liner:
>   RandomEnum r =
>   new RandomEnum(SomeEnum.class,
>RandomSource.create(RandomSou
> rce.SPLIT_MIX_64));
> vs the one I've suggested above?
>
> Gilles
>
> [...]
>>>
>>
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Re: [RNG] Generating for enums

[Gilles]

On Sat, 5 Aug 2017 09:47:20 -0700, Gary Gregory wrote:
On Fri, Aug 4, 2017 at 1:59 PM, Gilles  
wrote:



Hi Gary.

On Fri, 4 Aug 2017 11:10:57 -0700, Gary Gregory wrote:


For example, I have a enum like:

public enum CardinalDirection (NORTH,SOUTH,EAST,WEST)

and I want to say

traveler.travel(nextRandomDirection());

where

public CardinalDirection nextRandomDirection() {
   return rng.next(CardinalDirection.class);
}



Actually, "Commons RNG" already provides all the necessary 
functionality

for a one-liner:

---CUT---
import java.util.Arrays;
import org.apache.commons.rng.simple.RandomSource;
import org.apache.commons.rng.sampling.CollectionSampler;

CollectionSampler r
= new 
CollectionSampler<>(RandomSource.create(RandomSource.SPLIT_

MIX_64),
  
Arrays.asList(CardinalDirection.values()));


CardinalDirection e = r.sample();
---CUT---



Very nice, thank you.

I can see a wrapper for this boilerplate though:

public class RandomEnum {

private final Class enumClass;
private final CollectionSampler rng;

public RandomEnum(final Class enumClass) {
super();
this.enumClass = enumClass;
this.rng = new
CollectionSampler<>(RandomSource.create(RandomSource.SPLIT_MIX_64),
Arrays.asList(CellDirection.values()));

}

public CellDirection next() {
return rng.sample();
}

@Override
public String toString() {
return "RandomEnum [rng=" + rng + ", enumClass=" + enumClass + "]";
}
}


I guess there is a mix of generics and "specifics" here (cf.
"CellDirection"). And if you have only have a generic "E" in
that class, you won't be able to call "E.values()".
Then see also my other post:
  http://markmail.org/message/h63yb7ozk4nyjagj

However, what does one gain with having to call this one-liner:
  RandomEnum r =
  new RandomEnum(SomeEnum.class,
   
RandomSource.create(RandomSource.SPLIT_MIX_64));

vs the one I've suggested above?

Gilles


[...]


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Re: [RNG] Generating for enums

[Gary Gregory]

On Fri, Aug 4, 2017 at 1:59 PM, Gilles  wrote:

> Hi Gary.
>
> On Fri, 4 Aug 2017 11:10:57 -0700, Gary Gregory wrote:
>
>> For example, I have a enum like:
>>
>> public enum CardinalDirection (NORTH,SOUTH,EAST,WEST)
>>
>> and I want to say
>>
>> traveler.travel(nextRandomDirection());
>>
>> where
>>
>> public CardinalDirection nextRandomDirection() {
>>return rng.next(CardinalDirection.class);
>> }
>>
>
> Actually, "Commons RNG" already provides all the necessary functionality
> for a one-liner:
>
> ---CUT---
> import java.util.Arrays;
> import org.apache.commons.rng.simple.RandomSource;
> import org.apache.commons.rng.sampling.CollectionSampler;
>
> CollectionSampler r
> = new CollectionSampler<>(RandomSource.create(RandomSource.SPLIT_
> MIX_64),
>   Arrays.asList(CardinalDirection.values()));
>
> CardinalDirection e = r.sample();
> ---CUT---
>

Very nice, thank you.

I can see a wrapper for this boilerplate though:

public class RandomEnum {

private final Class enumClass;
private final CollectionSampler rng;

public RandomEnum(final Class enumClass) {
super();
this.enumClass = enumClass;
this.rng = new
CollectionSampler<>(RandomSource.create(RandomSource.SPLIT_MIX_64),
Arrays.asList(CellDirection.values()));

}

public CellDirection next() {
return rng.sample();
}

@Override
public String toString() {
return "RandomEnum [rng=" + rng + ", enumClass=" + enumClass + "]";
}
}

Gary



>
> Cheers,
> Gilles
>
>
>
>> Gary
>>
>> On Fri, Aug 4, 2017 at 11:02 AM, Amey Jadiye 
>> wrote:
>>
>> Hi,
>>>
>>> What's usecase for this BTW ? Might be unaware about requirement but this
>>> forced me to think why would someone need random enum ?
>>>
>>> Enums are generally "limited" immutable constants and people choose enum
>>> over the array of constants for good reason, however random provider
>>> seems
>>> best suited for choosing value from any Data-Structure holding "lot" of
>>> values.
>>>
>>> I think it's little weird but I would be happy  if someone explain
>>> advantages. :-)
>>>
>>> Regards,
>>> Amey
>>>
>>> On Fri, Aug 4, 2017, 11:17 PM Gary Gregory 
>>> wrote:
>>>
>>> > Hi All,
>>> >
>>> > Any thoughts on generation when you want to the domain to be an enum?
>>> >
>>> > SomeEnum e = UniformRandomProvider.next(SomeEnum);
>>> >
>>> > ?
>>> >
>>> > Is that too weird for this component?
>>> >
>>> > Gary
>>> >
>>>
>>>
>
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>

Re: [RNG] Generating for enums

[Gilles]

Hi Gary.

On Fri, 4 Aug 2017 11:10:57 -0700, Gary Gregory wrote:

For example, I have a enum like:

public enum CardinalDirection (NORTH,SOUTH,EAST,WEST)

and I want to say

traveler.travel(nextRandomDirection());

where

public CardinalDirection nextRandomDirection() {
   return rng.next(CardinalDirection.class);
}


Actually, "Commons RNG" already provides all the necessary 
functionality

for a one-liner:

---CUT---
import java.util.Arrays;
import org.apache.commons.rng.simple.RandomSource;
import org.apache.commons.rng.sampling.CollectionSampler;

CollectionSampler r
= new 
CollectionSampler<>(RandomSource.create(RandomSource.SPLIT_MIX_64),
  
Arrays.asList(CardinalDirection.values()));


CardinalDirection e = r.sample();
---CUT---


Cheers,
Gilles




Gary

On Fri, Aug 4, 2017 at 11:02 AM, Amey Jadiye  
wrote:



Hi,

What's usecase for this BTW ? Might be unaware about requirement but 
this

forced me to think why would someone need random enum ?

Enums are generally "limited" immutable constants and people choose 
enum
over the array of constants for good reason, however random provider 
seems
best suited for choosing value from any Data-Structure holding "lot" 
of

values.

I think it's little weird but I would be happy  if someone explain
advantages. :-)

Regards,
Amey

On Fri, Aug 4, 2017, 11:17 PM Gary Gregory  
wrote:


> Hi All,
>
> Any thoughts on generation when you want to the domain to be an 
enum?

>
> SomeEnum e = UniformRandomProvider.next(SomeEnum);
>
> ?
>
> Is that too weird for this component?
>
> Gary
>




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