On Sep 22, 2012, at 7:06 PM, Dave Angel wrote:
> On 09/22/2012 05:05 PM, Tim Roberts wrote:
>> Dennis Lee Bieber wrote:
>>> On 22 Sep 2012 01:36:59 GMT, Steven D'Aprano wrote:
For non IEEE 754 floating point systems, there is no telling how bad the
implementation could be :(
>>> L
On 23/09/12 01:06:08, Dave Angel wrote:
> On 09/22/2012 05:05 PM, Tim Roberts wrote:
>> Dennis Lee Bieber wrote:
>>> On 22 Sep 2012 01:36:59 GMT, Steven D'Aprano wrote:
For non IEEE 754 floating point systems, there is no telling how bad the
implementation could be :(
>>> Let's see
True. Seymour wanted all of the integer instructions to be combinatorial
logic, rather than iterative. Fortunately, since the floating point binary
point was to the right, it was trivial to pack integers to float, do a floating
computation, then unpack back to integer.
Apologize in advance fo
On 09/22/2012 05:05 PM, Tim Roberts wrote:
> Dennis Lee Bieber wrote:
>> On 22 Sep 2012 01:36:59 GMT, Steven D'Aprano wrote:
>>> For non IEEE 754 floating point systems, there is no telling how bad the
>>> implementation could be :(
>> Let's see what can be found...
>>
>> IBM 360: Same
Dennis Lee Bieber wrote:
>
>On 22 Sep 2012 01:36:59 GMT, Steven D'Aprano wrote:
>>
>> For non IEEE 754 floating point systems, there is no telling how bad the
>> implementation could be :(
>
> Let's see what can be found...
>
> IBM 360: Same as Sigma-6 (no surprise; hearsay is the Si
On Fri, 21 Sep 2012 15:23:41 -0700, Paul Rubin wrote:
> Steven D'Aprano writes:
>> Have I got this right? Is there a way to work out the gap between one
>> float and the next?
>
> Yes, 53-bit mantissa as people have mentioned. That tells you what ints
> can be exactly represented. But, arithme
On Fri, 21 Sep 2012 15:23:41 -0700, Paul Rubin wrote:
> Steven D'Aprano writes:
>> Have I got this right? Is there a way to work out the gap between one
>> float and the next?
>
> Yes, 53-bit mantissa as people have mentioned. That tells you what ints
> can be exactly represented. But, arithme
Steven D'Aprano writes:
> Have I got this right? Is there a way to work out the gap between one
> float and the next?
Yes, 53-bit mantissa as people have mentioned. That tells you what ints
can be exactly represented. But, arithmetic in some situations can have
a 1-ulp error. So I wonder if i
On Fri, 21 Sep 2012 17:29:13 +, Steven D'Aprano wrote:
> Python floats can represent exact integer values (e.g. 42.0), but above
> a certain value (see below), not all integers can be represented. For
> example:
>
> py> 1e16 == 1e16 + 1 # no such float as 10001.0 True py>
> 1e16
On 21/09/12 22:26:26, Dennis Lee Bieber wrote:
> On 21 Sep 2012 17:29:13 GMT, Steven D'Aprano
> declaimed the following in
> gmane.comp.python.general:
>
>>
>> The question is, what is the largest integer number N such that every
>> whole number between -N and N inclusive can be represented as a
On Fri, 21 Sep 2012 17:29:13 +, Steven D'Aprano wrote:
> The question is, what is the largest integer number N such that every
> whole number between -N and N inclusive can be represented as a float?
>
> If my tests are correct, that value is 9007199254740992.0 = 2**53.
>
> Have I got this r
Steven D'Aprano writes:
> Python floats can represent exact integer values (e.g. 42.0), but above a
> certain value (see below), not all integers can be represented. For
> example:
>
> py> 1e16 == 1e16 + 1 # no such float as 10001.0
> True
> py> 1e16 + 3 == 1e16 + 4 # or 1
On Fri, Sep 21, 2012 at 11:29 AM, Steven D'Aprano
wrote:
> The question is, what is the largest integer number N such that every
> whole number between -N and N inclusive can be represented as a float?
>
> If my tests are correct, that value is 9007199254740992.0 = 2**53.
>
> Have I got this right
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