BigFraction - double constructor

[axkr]

Maybe I don't understand this constructor correctly:

• https://github.com/Hipparchus-Math/hipparchus/blob/3c785280519b0c351003cf890f2ff4e917f6a354/hipparchus-core/src/main/java/org/hipparchus/fraction/BigFraction.java#L272

but what I'm looking for is a conversion where the result n - numerator and d - denominator of the v - double value satisfy the condition:

|(n/d) - v| < (10^c) / (d^2)

with c = -4 for example.

[maisonobe]

What about adding a stream generator that would produce a Stream<BigFraction>? This way, you could decide by yourself when to select the fraction you want using the Stream API, for example with filter and findFirst.

[axkr]

What about adding a stream generator that would produce a Stream<BigFraction>? This way, you could decide by yourself when to select the fraction you want using the Stream API, for example with filter and findFirst.

That seems to be a good idea. Do you have an example how to do it?

[maisonobe]

I have added static methods convergents in both Fraction and BigFraction to generate streams of fractions. You can look at the unit tests to see how one specific convergent can be selected from the stream.

Beware that your criterion with a threshold of 10^c/d^2 will probably never be fulfilled. One theorem for errors bounds in continued fractions states that |α - pₖ/qₖ| < 1/(qₖqₖ₊₁). With this boundary, the numerator is 1 and not 10^c, and the denominator qₖqₖ₊₁ is bigger than qₖ^2 as the denominator series is an increasing series.

[HannesWell]

I have added static methods convergents in both Fraction and BigFraction to generate streams of fractions. You can look at the unit tests to see how one specific convergent can be selected from the stream.

I also commented this on the commit: Shouldn't the spliterator created from the generatingIterator() also report the ORDERED characteristics, since the elements should not be arbitrarily reordered? Spliterator.DISTINCT | Spliterator.ORDERED