Re: [swift-users] Unsupported Float80 math functions and min/max behavior with Nan

2017-05-26 Thread Alex Blewitt via swift-users 
> On 26 May 2017, at 11:01, Antonino Ficarra via swift-users 
>  wrote:
> 
> - Why Swift continues to not support Float80 math functions?
> Example:
> 
> print("\( log( Float( 1.0 ) ) )")
> print("\( log( Double( 1.0 ) ) )")
> // print("\( log( Float80( 1.0 ) ) )")// don’t compile and logl is 
> unavailable

In this case, it's because 'log' only is defined for Float and Double:

log(Double) -> Double
log(x: Double) -> Double
log(x: Float) -> Float

The problem is that Float80 types are represented in C as long double, and 
currently the importer doesn't import things with long doubles. As a result, 
logl doesn't get imported which is why it's not seen:

 #include 

 double
 log(double x);

 long double
 logl(long double x);

The ones that do have Float80 support are done by hand, e.g.:

https://github.com/apple/swift/blob/19445cdb0e99eedf22390922e077d86f12123390/stdlib/public/SwiftShims/LibcShims.h#L138

The open bug is here, if you want to follow it:

https://bugs.swift.org/browse/SR-2046

> 
> - Why min and max continue to not act like fmin and fmax (IEEE 754 standard)?
> Example:
> 
> print("\( min( Double.nan,0.0 ) )")   // print nan (!)
> print("\( min( 0.0,Double.nan ) )")   // print 0.0
> print("\( max( Double.nan,0.0 ) )")   // print nan (!)
> print("\( max( 0.0,Double.nan ) )")   // print 0.0
> print("\n")
> 
> print("\( fmin( Double.nan,0.0 ) )")  // print 0.0
> print("\( fmin( 0.0,Double.nan ) )")  // print 0.0
> print("\( fmax( Double.nan,0.0 ) )")  // print 0.0
> print("\( fmax( 0.0,Double.nan ) )")  // print 0.0

There is another open bug here:

https://bugs.swift.org/browse/SR-1011 

Can you add your observations to that?

Thanks,

Alex___
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[swift-users] Unsupported Float80 math functions and min/max behavior with Nan

2017-05-26 Thread Antonino Ficarra via swift-users 
- Why Swift continues to not support Float80 math functions?
Example:

print("\( log( Float( 1.0 ) ) )")
print("\( log( Double( 1.0 ) ) )")
// print("\( log( Float80( 1.0 ) ) )")  // don’t compile and logl is unavailable

- Why min and max continue to not act like fmin and fmax (IEEE 754 standard)?
Example:

print("\( min( Double.nan,0.0 ) )") // print nan (!)
print("\( min( 0.0,Double.nan ) )") // print 0.0
print("\( max( Double.nan,0.0 ) )") // print nan (!)
print("\( max( 0.0,Double.nan ) )") // print 0.0
print("\n")

print("\( fmin( Double.nan,0.0 ) )")// print 0.0
print("\( fmin( 0.0,Double.nan ) )")// print 0.0
print("\( fmax( Double.nan,0.0 ) )")// print 0.0
print("\( fmax( 0.0,Double.nan ) )")// print 0.0
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[swift-users] Unsupported Float80 math functions and min/max behavior with Nan

2017-05-26 Thread Antonino Ficarra via swift-users 
- Why Swift continues to not support Float80 math functions?
Example:

print("\( log( Float( 1.0 ) ) )")
print("\( log( Double( 1.0 ) ) )")
// print("\( log( Float80( 1.0 ) ) )")  // don’t compile and logl is unavailable

- Why min and max continue to not act like fmin and fmax (IEEE 754 standard)?
Example:

print("\( min( Double.nan,0.0 ) )") // print nan (!)
print("\( min( 0.0,Double.nan ) )") // print 0.0
print("\( max( Double.nan,0.0 ) )") // print nan (!)
print("\( max( 0.0,Double.nan ) )") // print 0.0
print("\n")

print("\( fmin( Double.nan,0.0 ) )")// print 0.0
print("\( fmin( 0.0,Double.nan ) )")// print 0.0
print("\( fmax( Double.nan,0.0 ) )")// print 0.0
print("\( fmax( 0.0,Double.nan ) )")// print 0.0

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