Sense of Decimal class?

[ElMoe]

I don't understand the purpose of the Decimal class: what is the benefit of using decimal numbers instead of timeseries data?

[mdeverdelhan]

The Decimal type is the way I found to represent the numbers in ta4j. Originally we were using the double primitive type, but it resulted in huge approximations in calculations over time. See also:

• http://0.30000000000000004.com/
• Incorrect EMA calculation #4 (comment)
• Performance enhancements? #19 (comment)
• http://stackoverflow.com/questions/3413448/double-vs-bigdecimal
• http://stackoverflow.com/questions/1359817/using-bigdecimal-to-work-with-currencies
• And more, and more...

Now (i.e. it may change) Decimal delegates all the operations to BigDecimal, so it is based on BigDecimal's concepts (http://docs.oracle.com/javase/8/docs/api/java/math/BigDecimal.html).

Feel free to update the wiki with explications about that if you think it's unclear.

[ElMoe]

Thank for the introductory links to the Decimal topic!
You write that Decimal is somehow similar to BigDecimal. I encounter some difficulties when i try BigDecimal synax on Decimal, e.g.:
For BigDecimal it's: BigDecimal b = new BigDecimal("2.0");
For Decimal it's: Decimal b = Decimal.valueOf("2.0");

Two questions:
1.) What is there a reason that Decimal usages differ from BigDecimal?
2.) Is it possible to simply cast a BigDecimal simply into Decimal?

I'll try to put an introduction about Decimal into the wiki when i have basic understanding of the topic.

[mdeverdelhan]

1.) What is there a reason that Decimal usages differ from BigDecimal?

I chose to simplify (at least according to me) the management of the numbers in ta4j. BigDecimal comes with a bunch of features I don't use (Math contexts, management of VERY big numbers, divide-by-zero exception, ...).

2.) Is it possible to simply cast a BigDecimal simply into Decimal?

It would be possible if Decimal was extending BigDecimal. If so, I would have inherit all the features I mentioned above, and I plan (some day) to refactor this class to avoid using BigDecimal.

[ElMoe]

Okay, thank you for the explications.