[sf-lug] Old Calculator Problems

[Sujit K M]

On Wed, Aug 10, 2016 at 10:32 PM, Asheesh Laroia <asheesh at sandstorm.io> wrote:
> Hi Sujit,
>
> Very likely you are running into the inaccuracy of so-called "floating
> point" arithmetic. The topic is fascinating and mind-boggling, in my
> opinion.

I found something similar decimal rounding, but why do calculator
provide this by default,
or do we have to move to scientific calculator or might be this is the
accuracy in scientific
calculations.

http://www.calculatorsoup.com/calculators/math/roundingnumbers.php

>
> These are interesting references in my opinion:
>
> - "Why do simple math operations on floating point return unexpected
> (inaccurate) results in VB.Net and Python?"
> http://stackoverflow.com/questions/1594985/why-do-simple-math-operations-on-floating-point-return-unexpected-inaccurate-r

Found some thing that lets you go to 10 pow -28.
https://msdn.microsoft.com/en-us/library/6be1edhb(v=vs.110).aspx

or to 10 pow -15
https://mikemcl.github.io/decimal.js/

I found something wron in your stackover link. Python lets you round
to 10 pow -15.

> - "What you never wanted to know about floating point but will be forced to
> find out" http://www.volkerschatz.com/science/float.html
>
> - https://en.wikipedia.org/wiki/IEEE_floating_point

more on decimal rounding.
http://mathforum.org/dr.math/faq/faq.rounding.html
http://mathforum.org/library/drmath/view/58335.html

>
> Cheers,
>
> Asheesh.
>
>
>
> On Wed, Aug 10, 2016 at 8:34 AM, Sujit K M <kmsujit at gmail.com> wrote:
>>
>> Hi All,
>>
>> Just inspired by the Shell Scripting sciences I got inspired by something
>> else.
>>
>> I find something strange with my calculator it calculates from
>> the width of the decimal on my desktop.
>>
>> For Example
>>           1.  6*2/3 = 4
>>           2.  6*0.667 = 4.002
>>           3.  6*0.6666666667 =   4.0000000002
>>           4.  6*0.6666666666666667 = 4.
>>
>> Are there any standards for this. #4 should also lead to a value of
>> 4.0000000000000002.
>> Why is the calculator behaving strangely? There is no way in the world
>> width of the decimal
>> is affecting the result. Its a Desktop PC Calculator(Sounds Microsoft).
>>
>> What is the problem? I would love to dwell into the sciences that go
>> into, might be an
>> opensource calculator with source code ofcourse.
>>
>> Regards,
>> Sujit K M
>>
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>
>