Questions about Float.toString(float)

LP lp.coolbeans at proton.me
Sun Jun 5 07:59:59 UTC 2022


Hi,

(1)
float f = Float.intBitsToFloat(260046848);

JDK 17: Float.toString(f) -> 1.26217745E-29
master: Float.toString(f) -> 1.2621775E-29

BigDecimal.valueOf(Float.intBitsToFloat(260046847)) -> 1.2621773731219804E-29
BigDecimal.valueOf(Float.intBitsToFloat(260046848)) -> 1.2621774483536189E-29
BigDecimal.valueOf(Float.intBitsToFloat(260046849)) -> 1.2621775988168958E-29

What about 1.2621774E-29? I believe both 1.2621774E-29 and 1.2621775E-29 satisfy the Javadoc of Float.toString(float), so maybe it doesn't matter, but 1.2621774E-29 is closer to f.

(2)
float f = Float.intBitsToFloat(1291845637);

JDK 17: Float.toString(f) -> 1.34217808E8
master: Float.toString(f) -> 1.3421781E8

BigDecimal.valueOf(Float.intBitsToFloat(1291845636)) -> 134217792
BigDecimal.valueOf(Float.intBitsToFloat(1291845637)) -> 134217808
BigDecimal.valueOf(Float.intBitsToFloat(1291845638)) -> 134217824

What about 1.342178E8? 1.3421781E8 is an improvement over 1.34217808E8, but it's still not conforming to the Javadoc if 1.342178E8 is valid.

Apologies if I misunderstood something.

Thanks,
LP


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