• Dmitry Olshansky (18/18) Dec 04 2010 Well, to keep things short, double.min returns something weird.
• so (5/8) Dec 04 2010 That is something weird, you get a double smaller than the smallest
• so (4/4) Dec 04 2010 See what you mean, but it is the standard value from c's float.h.
• Dmitry Olshansky (5/11) Dec 04 2010 To prove the above point.
• Dmitry Olshansky (5/21) Dec 04 2010 the last line should be:
• Ellery Newcomer (3/19) Dec 04 2010 looks like double.min is returning double.min_normal
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (5/7) Dec 04 2010 Yeah, things got changed a while back for floating point types. .min now...
• sybrandy (4/20) Dec 04 2010 Perhaps this link can help:
• Don (3/23) Dec 04 2010 double.min is deprecated, for exactly this reason. That's why it's not
• Don (4/27) Dec 04 2010 And futher -- double.min_normal is the smallest normalised double. The
• Dmitry Olshansky (4/31) Dec 05 2010 I see, thanks for the explanation.

Dmitry Olshansky <dmitry.olsh gmail.com> writes:

Well,  to keep things short, double.min returns something weird.
See the following for demonstration:
import std.stdio;

void main(){
     double r = double.max, r2 = double.min;
     writeln(r);//1.79769e+308
     r *= 2;//test if it's max
     writeln(r); // infinity, ok

     writeln(r2);//2.22507e-308, wtf ?
     r2 /= 2.0;
     writeln(r2);// 1.11254e-308, a logical consequence of above

     double dmin = 5e-324;
     writeln(dmin);// 4.94066e-324
     dmin /= 2.0;
     writefln(dmin);// 0
}

-- 
Dmitry Olshansky

so <so so.do> writes:

 writeln(r2);//2.22507e-308, wtf ?

What is wrong? It is the smallest representable double. not (-double.max)

 r2 /= 2.0;
 writeln(r2);// 1.11254e-308, a logical consequence of above

That is something weird, you get a double smaller than the smallest  
representable!

-- 
Using Opera's revolutionary email client: http://www.opera.com/mail/

so <so so.do> writes:

See what you mean, but it is the standard value from c's float.h.

This is not my day, i should just stop posting...

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Using Opera's revolutionary email client: http://www.opera.com/mail/

Dmitry Olshansky <dmitry.olsh gmail.com> writes:

On 05.12.2010 0:48, so wrote:
 writeln(r2);//2.22507e-308, wtf ?

 What is wrong? It is the smallest representable double. not (-double.max)

The smallest is 5e-324 as I (hopefully) showed.

 r2 /= 2.0;
 writeln(r2);// 1.11254e-308, a logical consequence of above

 That is something weird, you get a double smaller than the smallest 
 representable!

To prove the above point.

-- 
Dmitry Olshansky

Dmitry Olshansky <dmitry.olsh gmail.com> writes:

On 05.12.2010 0:22, Dmitry Olshansky wrote:
 Well,  to keep things short, double.min returns something weird.
 See the following for demonstration:
 import std.stdio;

 void main(){
     double r = double.max, r2 = double.min;
     writeln(r);//1.79769e+308
     r *= 2;//test if it's max
     writeln(r); // infinity, ok

     writeln(r2);//2.22507e-308, wtf ?
     r2 /= 2.0;
     writeln(r2);// 1.11254e-308, a logical consequence of above

     double dmin = 5e-324;
     writeln(dmin);// 4.94066e-324
     dmin /= 2.0;
     writefln(dmin);// 0
 }

the last line should be:
writeln(dmin); //0

-- 
Dmitry Olshansky

Ellery Newcomer <ellery-newcomer utulsa.edu> writes:

On 12/04/2010 03:22 PM, Dmitry Olshansky wrote:
 Well, to keep things short, double.min returns something weird.
 See the following for demonstration:
 import std.stdio;

 void main(){
 double r = double.max, r2 = double.min;
 writeln(r);//1.79769e+308
 r *= 2;//test if it's max
 writeln(r); // infinity, ok

 writeln(r2);//2.22507e-308, wtf ?
 r2 /= 2.0;
 writeln(r2);// 1.11254e-308, a logical consequence of above

 double dmin = 5e-324;
 writeln(dmin);// 4.94066e-324
 dmin /= 2.0;
 writefln(dmin);// 0
 }

looks like double.min is returning double.min_normal

oddly enough, double.min is undefined in the spec

=?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:

Ellery Newcomer wrote:
 looks like double.min is returning double.min_normal

 oddly enough, double.min is undefined in the spec

Yeah, things got changed a while back for floating point types. .min now 
returns the minimum normal. To get the actual minimum value, we need to 
use the negative of .max.

Ali

sybrandy <sybrandy gmail.com> writes:

On 12/04/2010 04:22 PM, Dmitry Olshansky wrote:
 Well, to keep things short, double.min returns something weird.
 See the following for demonstration:
 import std.stdio;

 void main(){
 double r = double.max, r2 = double.min;
 writeln(r);//1.79769e+308
 r *= 2;//test if it's max
 writeln(r); // infinity, ok

 writeln(r2);//2.22507e-308, wtf ?
 r2 /= 2.0;
 writeln(r2);// 1.11254e-308, a logical consequence of above

 double dmin = 5e-324;
 writeln(dmin);// 4.94066e-324
 dmin /= 2.0;
 writefln(dmin);// 0
 }

Perhaps this link can help:

https://secure.wikimedia.org/wikipedia/en/wiki/IEEE_754-1985

Casey

Don <nospam nospam.com> writes:

Dmitry Olshansky wrote:
 Well,  to keep things short, double.min returns something weird.
 See the following for demonstration:
 import std.stdio;
 
 void main(){
     double r = double.max, r2 = double.min;
     writeln(r);//1.79769e+308
     r *= 2;//test if it's max
     writeln(r); // infinity, ok
 
     writeln(r2);//2.22507e-308, wtf ?
     r2 /= 2.0;
     writeln(r2);// 1.11254e-308, a logical consequence of above
 
     double dmin = 5e-324;
     writeln(dmin);// 4.94066e-324
     dmin /= 2.0;
     writefln(dmin);// 0
 }
 

double.min is deprecated, for exactly this reason. That's why it's not 
mentioned in the spec.

Don <nospam nospam.com> writes:

Don wrote:
 Dmitry Olshansky wrote:
 Well,  to keep things short, double.min returns something weird.
 See the following for demonstration:
 import std.stdio;

 void main(){
     double r = double.max, r2 = double.min;
     writeln(r);//1.79769e+308
     r *= 2;//test if it's max
     writeln(r); // infinity, ok

     writeln(r2);//2.22507e-308, wtf ?
     r2 /= 2.0;
     writeln(r2);// 1.11254e-308, a logical consequence of above

     double dmin = 5e-324;
     writeln(dmin);// 4.94066e-324
     dmin /= 2.0;
     writefln(dmin);// 0
 }

 double.min is deprecated, for exactly this reason. That's why it's not 
 mentioned in the spec.

And futher -- double.min_normal is the smallest normalised double. The 
smallest representable double is (double.min_normal * double.epsilon).

double.min is a silly name, so it has been deprecated.

Dmitry Olshansky <dmitry.olsh gmail.com> writes:

On 05.12.2010 8:59, Don wrote:
 Don wrote:
 Dmitry Olshansky wrote:
 Well,  to keep things short, double.min returns something weird.
 See the following for demonstration:
 import std.stdio;

 void main(){
     double r = double.max, r2 = double.min;
     writeln(r);//1.79769e+308
     r *= 2;//test if it's max
     writeln(r); // infinity, ok

     writeln(r2);//2.22507e-308, wtf ?
     r2 /= 2.0;
     writeln(r2);// 1.11254e-308, a logical consequence of above

     double dmin = 5e-324;
     writeln(dmin);// 4.94066e-324
     dmin /= 2.0;
     writefln(dmin);// 0
 }

 double.min is deprecated, for exactly this reason. That's why it's 
 not mentioned in the spec.

 And futher -- double.min_normal is the smallest normalised double. The 
 smallest representable double is (double.min_normal * double.epsilon).

 double.min is a silly name, so it has been deprecated.

I see, thanks for the explanation.

-- 
Dmitry Olshansky