Thanks for the additional report.
The results reflect the typemap for conversions from perl scalars
to PDL types which tries to avoid unnecessary type promotions
(if you start with a byte value, you probably don't want the result
as a 64bit int at the end). PDL used to use doubles as the catch
all type. That doesn't work for 64bit integers since they are not
representable as double (ieee with only a 52bit mantissa).
floor(1.3)->floor(double) since 1.3 is not exact in float or int
floor(1)->floor(byte) since 1 is an int < 256
floor(1.0)->floor(float) since 1.0 is double or float and 1.0 is
exact as float
NOTE: This is an explanation for what you have reported not a defense.
Thanks for the investigations,
Chris
On 6/18/2015 03:59, Marek Gierliński wrote:
Recently I have reported problems with using results of stats() as
scalars. Today I found that another of my scripts, that used to work
in older PDL versions, is failing. The problem is very similar, using
one-element piddles in scalar context gives almost random results.
Here it is:
pdl> $x = floor(1.3)
pdl> p $x
1
pdl> $x += 0.1
pdl> p $x
1.1
pdl> $x = floor(1)
pdl> p $x
1
pdl> $x += 0.1
pdl> p $x
1
when taking floor() of an integer number, I cannot increment it
afterwards. No problems when I take floor() of a non-integer. I think
in this particular case the problem is with the type:
pdl> $x = floor(1.1); p $x->info
PDL: Double D []
pdl> $x = floor(1); p $x->info
PDL: Byte D []
Suddenly, the type is changed and I suppose 'Byte' doesn't take +=0.1.
This is a bit random, unexpected and unpredictable. In particular,
there is inconsistency:
pdl> $x = floor(1); p $x->info
PDL: Byte D []
pdl> $y = pdl(1); p $y->info
PDL: Double D []
Has something been changed in the recent months (or even years, as we
used to use quite old version of PDL for years and only recently
upgraded to 2.007) in the way types are converted and one-element
piddles are treated in the scalar context? I'm just discovering more
and more of my scripts doing weird things...
Cheers,
Marek
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