spark-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From tao zhan <zhanta...@gmail.com>
Subject Re: Question on Spark code
Date Mon, 24 Jul 2017 04:00:34 GMT
Get it, thank you!

On Mon, Jul 24, 2017 at 11:50 AM, Reynold Xin <rxin@databricks.com> wrote:

> This is a standard practice used for chaining, to support
>
> a.setStepSize(..)
>   .set setRegParam(...)
>
>
> On Sun, Jul 23, 2017 at 8:47 PM, tao zhan <zhantao92@gmail.com> wrote:
>
>> Thank you for replying.
>> But I do not get it completely, why does the "this.type“” necessary?
>> why could not it be like:
>>
>> def setStepSize(step: Double): Unit = {
>>     require(step > 0,
>>       s"Initial step size must be positive but got ${step}")
>>     this.stepSize = step
>> }
>>
>> On Mon, Jul 24, 2017 at 11:29 AM, M. Muvaffak ONUŞ <
>> onus.muvaffak@gmail.com> wrote:
>>
>>> Doesn't it mean the return type will be type of "this" class. So, it
>>> doesn't have to be this instance of the class but it has to be type of this
>>> instance of the class. When you have a stack of inheritance and call that
>>> function, it will return the same type with the level that you called it.
>>>
>>> On Sun, Jul 23, 2017 at 8:20 PM Reynold Xin <rxin@databricks.com> wrote:
>>>
>>>> It means the same object ("this") is returned.
>>>>
>>>> On Sun, Jul 23, 2017 at 8:16 PM, tao zhan <zhantao92@gmail.com> wrote:
>>>>
>>>>> Hello,
>>>>>
>>>>> I am new to scala and spark.
>>>>> What does the "this.type" in set function for?
>>>>>
>>>>>
>>>>> ​
>>>>> https://github.com/apache/spark/blob/481f0792944d9a77f0fe8b5
>>>>> e2596da1d600b9d0a/mllib/src/main/scala/org/apache/spark/mlli
>>>>> b/optimization/GradientDescent.scala#L48
>>>>>
>>>>> Thanks!
>>>>>
>>>>> Zhan
>>>>>
>>>>
>>>>
>>
>

Mime
View raw message