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digitalmars.D.bugs - [Issue 6154] New: std.math.abs on std.complex numbers too

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=6154

           Summary: std.math.abs on std.complex numbers too
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: Phobos
        AssignedTo: nobody puremagic.com
        ReportedBy: bearophile_hugs eml.cc



I'd like std.math.abs to perform what std.complex.Complex!T.abs does. So I will
be able to use it functionally (currently std.math.abs is able to work on the
built-in complex numbers too). This means I'd like this code to work:

import std.stdio, std.math, std.algorithm, std.complex;
void main() {
    alias Complex!double C;
    C[] array2 = [C(1,2), C(2,4)];
    auto m2 = map!abs(array2);
    writeln(m2);
}



In DMD 2.053 similar code with built-in complex numbers works:

import std.stdio, std.math, std.algorithm;
void main() {
    cdouble[] array1 = [1+2i, 2+4i];
    auto m1 = map!abs(array1);
    writeln(m1);
}


In DMD 2.053 if you want to do the same with complex numbers you need to write:

import std.stdio, std.math, std.algorithm, std.complex;
void main() {
    alias Complex!double C;
    C[] array2 = [C(1,2), C(2,4)];
    auto m2 = map!((c){ return c.abs(); })(array2);
    writeln(m2);
}

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Jun 14 2011
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=6154


kennytm gmail.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |kennytm gmail.com





 In DMD 2.053 if you want to do the same with complex numbers you need to write:
 
 import std.stdio, std.math, std.algorithm, std.complex;
 void main() {
     alias Complex!double C;
     C[] array2 = [C(1,2), C(2,4)];
     auto m2 = map!((c){ return c.abs(); })(array2);
     writeln(m2);
 }


    auto m2 = map!`a.abs()`(array2);

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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     auto m2 = map!`a.abs()`(array2);


Right. But std.math.abs has to work on complex numbers too, as before, for
polymorphism, and for a serious integration of complex numbers in Phobos.

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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Don <clugdbug yahoo.com.au> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |clugdbug yahoo.com.au






 

     auto m2 = map!`a.abs()`(array2);


 
 Right. But std.math.abs has to work on complex numbers too, as before,


No, it does not, and will not.
BTW that approach would lead to executable bloat.


 for polymorphism, and for a serious integration of complex numbers in Phobos.


No. This is what overload sets are for.

Complex must not be given special treatment ahead of user-defined types.
Otherwise, user-defined types become second-class citizens.

(std.math.abs is a bit of a problem at the moment, there are a couple of
functions in std.math which have range versions, which IMHO have no business
being in there).

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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     auto m2 = map!`a.abs()`(array2);


 
 Right. But std.math.abs has to work on complex numbers too, as before, for
 polymorphism, and for a serious integration of complex numbers in Phobos.


Right, but why must it be std.math.abs? Putting the free function as
std.complex.abs works too.

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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 Putting the free function as std.complex.abs works too.


OK.

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Jun 15 2011
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=6154


Lars T. Kyllingstad <bugzilla kyllingen.net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |bugzilla kyllingen.net
         Resolution|                            |FIXED



05:51:12 PDT ---
std.complex.abs() was added in May 2012.

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Aug 04 2013