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SethTisue merged 1 commit into from
Feb 16, 2017
Merged

SI-10148 Follow Java for float literals #5648

SethTisue merged 1 commit into from
Feb 16, 2017

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@som-snytt som-snytt commented Jan 17, 2017 •
edited by SethTisue
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Use Float.parseFloat instead of converting from Double.
Error when a value rounds to zero.

JIRA: https://issues.scala-lang.org/browse/SI-10148

@scala-jenkins scala-jenkins added this to the 2.12.2 milestone Jan 17, 2017
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SI-10148 Follow Java for float literals
a262aab 
Use `Float.parseFloat` instead of converting from Double.
Error when a value rounds to zero.
janekdb
janekdb reviewed Jan 18, 2017
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test/files/run/literals.scala
check_success("1.00000017881393421514957253748434595763683319091796875001f == 1.0000001f",
1.00000017881393421514957253748434595763683319091796875001f,
1.0000001f)
check_success("3.4028235E38f == Float.MaxValue", 3.4028235E38f, Float.MaxValue)
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Why no check using Float.MinValue? Probably demonstrating my ignorance of something here!

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@som-snytt som-snytt Jan 18, 2017

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My name isn't ScalaCheck. Also, the difference is just a sign bit which is turned on by a leading midlevel horizontal bar symbol. Of course, the test wouldn't hurt.

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@janekdb janekdb Jan 18, 2017 •
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Ignorance of IEEE 754 fully demoed (by me)! Java MIN_VALUE is not the negative float with the greatest magnitude but the smallest positive nonzero value.

https://docs.oracle.com/javase/7/docs/api/java/lang/Float.html#MIN_VALUE

Having said that why not add a check for the effect of a leading hyphen-minus?

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OK, if I have time to switch my repo back to this branch on my old home machine.

There's a puzzler (BTW) that turns on the fact that -1.0f is a literal. See here.

@adriaanm adriaanm requested a review from SethTisue February 16, 2017 20:34
@SethTisue SethTisue merged commit 955b779 into scala:2.12.x Feb 16, 2017
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SethTisue commented Feb 16, 2017

thx AP!

@som-snytt som-snytt deleted the issue/10148 branch February 16, 2017 22:25
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SethTisue commented Feb 17, 2017

this turned up in the community build:

[breeze] [error] /Users/tisue/community.212/target-0.9.7-RC1/project-builds/breeze-ef73d8d5e54fa4ff81b6f6abfe9e238739cc5d8a/math/src/test/scala/breeze/signal/filter/DesignFilterTest.scala:53: double precision floating point number too small
[breeze] [error]   val testFirwin4 = DenseVector( -0.000000000000000000e+00, 3.794040820411270776e-01, 3.794040820411272441e-01, -0.000000000000000000e+00)
[breeze] [error]                                   ^
[breeze] [error] /Users/tisue/community.212/target-0.9.7-RC1/project-builds/breeze-ef73d8d5e54fa4ff81b6f6abfe9e238739cc5d8a/math/src/test/scala/breeze/signal/filter/DesignFilterTest.scala:53: double precision floating point number too small
[breeze] [error]   val testFirwin4 = DenseVector( -0.000000000000000000e+00, 3.794040820411270776e-01, 3.794040820411272441e-01, -0.000000000000000000e+00)
[breeze] [error]                                                                                                                  ^
[breeze] [error] two errors found

is this a regression, or is the code in breeze erroneous...?

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som-snytt commented Feb 17, 2017

Zero is pretty small. It looks like the little heuristic for testing whether you said zero is not right.

som-snytt
som-snytt commented Feb 17, 2017
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@SethTisue SethTisue mentioned this pull request Feb 18, 2017
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@som-snytt som-snytt mentioned this pull request Feb 18, 2017
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@SethTisue SethTisue mentioned this pull request Mar 7, 2017
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@scabug scabug mentioned this pull request Apr 7, 2017
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@som-snytt som-snytt mentioned this pull request Feb 3, 2020
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