[AccessD] Rounding Error - A2K

Still another question...

Using the BEU I am creating new factor fields as double and using update SQL
placing the factors into the new fields.
The problem is they get placed in the new double fields with about 20
decimals.

Is there a way to insert the factors into the new double fields with just
the appropriate 6 decimals?

Reuben Cummings
GFC, LLC
812.523.1017


> -----Original Message-----
> From: accessd-bounces at databaseadvisors.com 
> [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of 
> Charlotte Foust
> Sent: Wednesday, December 09, 2009 4:07 PM
> To: Access Developers discussion and problem solving
> Subject: Re: [AccessD] Rounding Error - A2K
> 
> 
> Are you working with singles or doubles and what precision.  
> All those things matter in Access.  Plus floating point 
> values are notorious for adding stray decimal values even in 
> addition, let alone multiplication.
> 
> Charlotte Foust 
> 
> -----Original Message-----
> From: accessd-bounces at databaseadvisors.com 
> [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of 
> Reuben Cummings
> Sent: Wednesday, December 09, 2009 12:30 PM
> To: 'Access Developers discussion and problem solving'
> Subject: Re: [AccessD] Rounding Error - A2K
> 
> Thanks.  Interesting stuff.
> 
> I wrote a quick function that merely evaluates the 3rd 
> decimal and either adds .01 or doesn't in order to test the 
> results I was getting.
> 
> Turns out the error is not in the Rounding.
> 
> THE ERROR IS IN THE MATH TO GET THE NUMBER TO BE ROUNDED.
> 
> 
> In Access 332,215.50 * .258099 = 85744.48492
> In Excel or on a calculator...         85744.48833
> 
> The other problem...
> In Access 98518.68 * .253696 = 24993.79451
> In Excel or calculator...             24993.79504
> 
> If I "Hard Code" the calc into a query I get the .48833.
> But if I let the query do the math to the 332215.50 and then 
> multiply I get
> .48492
> 
> I've looked for extra decimals, but see nothing.
> 
> Any ideas?
> 
> Reuben Cummings
> GFC, LLC
> 812.523.1017
> 
> 
> > -----Original Message-----
> > From: accessd-bounces at databaseadvisors.com
> > [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Gustav 
> > Brock
> > Sent: Wednesday, December 09, 2009 1:55 PM
> > To: accessd at databaseadvisors.com
> > Subject: Re: [AccessD] Rounding Error - A2K
> > 
> > 
> > Hi Reuben
> > 
> > Round in Access is known to be buggy.
> > If you are interested in rounding and how to optimise this 
> regarding 
> > speed while still being accurate, read on here:
> > 
> >   http://www.xbeat.net/vbspeed/c_Round.htm
> > 
> > Note that the absolutely simplest (but slowest) method to 
> perform 100% 
> > correct (mathematical) rounding is ... Format!
> > 
> > /gustav
> > 
> > 
> > >>> accessd at gfconsultants.com 09-12-2009 19:39:40 >>>
> > Can anyone explain to me, given the following two sets of 
> numbers why 
> > I get the answers I do in Access?
> > I'll also provide the answers to the same numbers and equations in 
> > Excel.
> > Access simply seems to be rounding wrong.
> > And these are only 2 out of 22.  The other 20 are correct.
> > 
> > =============================================
> > .47
> > 206104.58
> > 118507.98
> > 3312.20
> > 16
> > 4274.27
> > Total = 332215.50
> > 
> > % = .258099
> > 
> > If I do Round(Total*%,2) I get 85,744.48 In excel I get 85,744.49
> > 
> > The number, before rounding is 85744.48833
> > 
> > =============================================
> > 
> > The 2nd set is
> > 66986.81
> > 29694.41
> > 1837.46
> > Total = 98518.68
> > 
> > % = .253696
> > 
> > Round(Total*%,2) in Access gives me 24,993.79
> > 
> > Excel gives me 24,993.80
> > 
> > Before rounding it is 24993.79504
> > =============================================
> > 
> > Why the rounding errors?
> > 
> > Reuben Cummings
> > GFC, LLC
> > 812.523.1017
> > 
> > 
> > 
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> > 
> 
> 
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