On Sat, Jun 26, 2010 at 9:32 AM, Craig DeForest
<[email protected]> wrote:
> You are confusing direct assignment and computed assignment. "$b=$b*10"
> creates a new PDL and puts it in the scalar named $b, dropping the old one
> (and its dataflow connection to $a) on the floor. use computed assignment
> (".=") instead.
>
Fair enough. But, add this to the list of inconsistencies.
perldl> $a = sequence 5
perldl> p $a
[0 1 2 3 4]
perldl> $b = $a->slice('1:3')
perldl> $b = $b + 5
perldl> p $b
[6 7 8]
However....
perldl> p $a
[0 1 2 3 4]
perldl>
perldl> $a = sequence 5
perldl> p $a
[0 1 2 3 4]
perldl> $b = $a->slice('1:3')
perldl> $b += 5
perldl> p $b
[6 7 8]
perldl> p $a
[0 6 7 8 4]
perldl>
Similar to the sin($a) working, but int($a) not working. Yes, I know
that int() is not a PDL function, but if sin(), cos(), etc. can be
expected to work, if certain arithmetic operators are expected to
work, then all of them should be expected to work.
Consistent interfaces are the hallmark of easy to learn, effective and
powerful software. PDL is two out of three, but it would be nice for
it to be 3 out of 3.
> (Mobile)
>
>
> On Jun 26, 2010, at 8:12 AM, P Kishor <[email protected]> wrote:
>
>> perldl> $a = sequence 5, 4, 2
>> perldl> p $a
>> [
>> [
>> [ 0 1 2 3 4]
>> [ 5 6 7 8 9]
>> [10 11 12 13 14]
>> [15 16 17 18 19]
>> ]
>> [
>> [20 21 22 23 24]
>> [25 26 27 28 29]
>> [30 31 32 33 34]
>> [35 36 37 38 39]
>> ]
>> ]
>>
>> **************
>> perldl> $b = $a->slice(':,1:2,:')
>> perldl> $b = $b * 10
>> perldl> p $a
>> [
>> [
>> [ 0 1 2 3 4]
>> [ 5 6 7 8 9]
>> [10 11 12 13 14]
>> [15 16 17 18 19]
>> ]
>> [
>> [20 21 22 23 24]
>> [25 26 27 28 29]
>> [30 31 32 33 34]
>> [35 36 37 38 39]
>> ]
>> ]
>> perldl> p $b
>> [
>> [
>> [ 50 60 70 80 90]
>> [100 110 120 130 140]
>> ]
>> [
>> [250 260 270 280 290]
>> [300 310 320 330 340]
>> ]
>> ]
>>
>> So, what happened here? Why does multiplying the slice by 10 not
>> change $a as well?
>>
>> Turning on dataflow at *************** above with $a->doflow doesn't
>> help as well (although, by my understanding, it shouldn't be needed
>>
>> --
>> Puneet Kishor
>>
>> _______________________________________________
>> Perldl mailing list
>> [email protected]
>> http://mailman.jach.hawaii.edu/mailman/listinfo/perldl
>>
>
--
Puneet Kishor http://www.punkish.org
Carbon Model http://carbonmodel.org
Charter Member, Open Source Geospatial Foundation http://www.osgeo.org
Science Commons Fellow, http://sciencecommons.org/about/whoweare/kishor
Nelson Institute, UW-Madison http://www.nelson.wisc.edu
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