From the documentation about Decimal.Round....
"When d is exactly halfway between two rounded values, the result is the
rounded value that has an even digit in the far right decimal position. For
example, when rounded to two decimals, the value 2.345 becomes 2.34 and the
value 2.355 becomes 2.36. This process is known as rounding toward even, or
rounding to nearest."
I'd have to disagree. I'd go for something more like "This process is known
is arbitrarily ignoring a de facto standard." Does anyone have a sensible
method of returning the correct rounded value i.e. without resorting to
decimal.round(x+0.00000001,2)
And has anyone got any justification for this ludicrousness?
--
For real reply address, lose the cash www.realuk.co.uk 17 2482
This is actually pretty standard. Do a search on google for papers and
such....
"Rob Oldfield" <r$ob@oldfi$eld100.freese$rve.c$o.uk> wrote in message
news:OD**************@TK2MSFTNGP12.phx.gbl... From the documentation about Decimal.Round....
"When d is exactly halfway between two rounded values, the result is the rounded value that has an even digit in the far right decimal position.
For example, when rounded to two decimals, the value 2.345 becomes 2.34 and
the value 2.355 becomes 2.36. This process is known as rounding toward even,
or rounding to nearest."
I'd have to disagree. I'd go for something more like "This process is
known is arbitrarily ignoring a de facto standard." Does anyone have a sensible method of returning the correct rounded value i.e. without resorting to decimal.round(x+0.00000001,2)
And has anyone got any justification for this ludicrousness?
-- For real reply address, lose the cash www.realuk.co.uk
Ooops.. Its called Banker's rounding
"NoOne" <No@Where.com> wrote in message
news:eN*************@TK2MSFTNGP09.phx.gbl... This is actually pretty standard. Do a search on google for papers and such....
"Rob Oldfield" <r$ob@oldfi$eld100.freese$rve.c$o.uk> wrote in message news:OD**************@TK2MSFTNGP12.phx.gbl... From the documentation about Decimal.Round....
"When d is exactly halfway between two rounded values, the result is the rounded value that has an even digit in the far right decimal position. For example, when rounded to two decimals, the value 2.345 becomes 2.34 and the value 2.355 becomes 2.36. This process is known as rounding toward even, or rounding to nearest."
I'd have to disagree. I'd go for something more like "This process is known is arbitrarily ignoring a de facto standard." Does anyone have a
sensible method of returning the correct rounded value i.e. without resorting to decimal.round(x+0.00000001,2)
And has anyone got any justification for this ludicrousness?
-- For real reply address, lose the cash www.realuk.co.uk
I repeat. It's lunacy. It might be a good idea, but the fact is that
NOBODY ACTUALLY DOES IT THIS WAY.
Well, that might be an exaggeration, but very few people.
--
For real reply address, lose the cash www.realuk.co.uk
"NoOne" <No@Where.com> wrote in message
news:#k**************@TK2MSFTNGP10.phx.gbl... Ooops.. Its called Banker's rounding
"NoOne" <No@Where.com> wrote in message news:eN*************@TK2MSFTNGP09.phx.gbl... This is actually pretty standard. Do a search on google for papers and such....
"Rob Oldfield" <r$ob@oldfi$eld100.freese$rve.c$o.uk> wrote in message news:OD**************@TK2MSFTNGP12.phx.gbl... From the documentation about Decimal.Round....
"When d is exactly halfway between two rounded values, the result is
the rounded value that has an even digit in the far right decimal
position. For example, when rounded to two decimals, the value 2.345 becomes 2.34
and the value 2.355 becomes 2.36. This process is known as rounding toward
even, or rounding to nearest."
I'd have to disagree. I'd go for something more like "This process is known is arbitrarily ignoring a de facto standard." Does anyone have a sensible method of returning the correct rounded value i.e. without resorting
to decimal.round(x+0.00000001,2)
And has anyone got any justification for this ludicrousness?
-- For real reply address, lose the cash www.realuk.co.uk
write your own method then.
make an enum of values ( like odd, even digits )
and make up a rule.
"Rob Oldfield" <r$ob@oldfi$eld100.freese$rve.c$o.uk> wrote in message
news:OD**************@TK2MSFTNGP12.phx.gbl... From the documentation about Decimal.Round....
"When d is exactly halfway between two rounded values, the result is the rounded value that has an even digit in the far right decimal position.
For example, when rounded to two decimals, the value 2.345 becomes 2.34 and
the value 2.355 becomes 2.36. This process is known as rounding toward even,
or rounding to nearest."
I'd have to disagree. I'd go for something more like "This process is
known is arbitrarily ignoring a de facto standard." Does anyone have a sensible method of returning the correct rounded value i.e. without resorting to decimal.round(x+0.00000001,2)
And has anyone got any justification for this ludicrousness?
-- For real reply address, lose the cash www.realuk.co.uk
I could do that, yes. The reason for the question is with the hope that
somebody else has already done it and would be willing to share their code.
I still say that it's ludicrous that MS didn't get it right to start off
with. Would it be OK if the '+' operator worked perfectly except on
Tuesday's. Perfectly simple to replace function add(x,y) with....
dim newY
if day=tuesday
newY=y*-1
add=x-y
else
add=x+y
end if
....but still monumentally stupid.
--
For real reply address, lose the cash www.realuk.co.uk
"c# newbie" <no****@leave.me.alone> wrote in message
news:31******************************@news.teranew s.com... write your own method then.
make an enum of values ( like odd, even digits ) and make up a rule.
"Rob Oldfield" <r$ob@oldfi$eld100.freese$rve.c$o.uk> wrote in message news:OD**************@TK2MSFTNGP12.phx.gbl... From the documentation about Decimal.Round....
"When d is exactly halfway between two rounded values, the result is the rounded value that has an even digit in the far right decimal position. For example, when rounded to two decimals, the value 2.345 becomes 2.34 and the value 2.355 becomes 2.36. This process is known as rounding toward even, or rounding to nearest."
I'd have to disagree. I'd go for something more like "This process is known is arbitrarily ignoring a de facto standard." Does anyone have a
sensible method of returning the correct rounded value i.e. without resorting to decimal.round(x+0.00000001,2)
And has anyone got any justification for this ludicrousness?
-- For real reply address, lose the cash www.realuk.co.uk
MS has a reason for doing it, but you're not alone in your frustration, b/c
many don't realize it until after it's too late. At least an overload
should have been provided so you can use either method IMHO.
"Rob Oldfield" <r$ob@oldfi$eld100.freese$rve.c$o.uk> wrote in message
news:OD**************@TK2MSFTNGP12.phx.gbl... From the documentation about Decimal.Round....
"When d is exactly halfway between two rounded values, the result is the rounded value that has an even digit in the far right decimal position.
For example, when rounded to two decimals, the value 2.345 becomes 2.34 and
the value 2.355 becomes 2.36. This process is known as rounding toward even,
or rounding to nearest."
I'd have to disagree. I'd go for something more like "This process is
known is arbitrarily ignoring a de facto standard." Does anyone have a sensible method of returning the correct rounded value i.e. without resorting to decimal.round(x+0.00000001,2)
And has anyone got any justification for this ludicrousness?
-- For real reply address, lose the cash www.realuk.co.uk
William Ryan <do********@comcast.nospam.net> wrote: MS has a reason for doing it, but you're not alone in your frustration, b/c many don't realize it until after it's too late. At least an overload should have been provided so you can use either method IMHO.
Rather than an overload, there should be an enumeration of rounding
types, or possibly something like the Encoding hierarchy.
--
Jon Skeet - <sk***@pobox.com> http://www.pobox.com/~skeet
If replying to the group, please do not mail me too
Rob Oldfield <r$ob@oldfi$eld100.freese$rve.c$o.uk> wrote: I repeat. It's lunacy. It might be a good idea, but the fact is that NOBODY ACTUALLY DOES IT THIS WAY.
Well, that might be an exaggeration, but very few people.
I suspect that decimal is generally intended for financial
applications, and given that the name is "banker's rounding" my guess
is that it's not uncommon in that sector. I don't personally have a lot
of experience with the financial sector - do you?
--
Jon Skeet - <sk***@pobox.com> http://www.pobox.com/~skeet
If replying to the group, please do not mail me too
The app that I'm writing that this error has just come up is for an
investment house. When I told their accounts manager that this was the
problem his reaction was "That's absolutely ludicrous. I've never heard of
anyone doing it that way."
This is in the UK though, it may be that things are different in the US, but
certainly 'rounding' over here is 100% 'round halves upwards'.
--
For real reply address, lose the cash www.realuk.co.uk
"Jon Skeet [C# MVP]" <sk***@pobox.com> wrote in message
news:MP************************@msnews.microsoft.c om... Rob Oldfield <r$ob@oldfi$eld100.freese$rve.c$o.uk> wrote: I repeat. It's lunacy. It might be a good idea, but the fact is that NOBODY ACTUALLY DOES IT THIS WAY.
Well, that might be an exaggeration, but very few people.
I suspect that decimal is generally intended for financial applications, and given that the name is "banker's rounding" my guess is that it's not uncommon in that sector. I don't personally have a lot of experience with the financial sector - do you?
-- Jon Skeet - <sk***@pobox.com> http://www.pobox.com/~skeet If replying to the group, please do not mail me too
....and something else I didn't think of in my previous answer....
The vast majority of bankers thoughout the world are using Excel. The round
function in Excel works on the 'round halves up' method. Either they all
know about the difference between their hand-crafted figures and the central
office system and they've given themselves a way around it, or there are a
lot of pennies going missing somewhere.
Next question: can you think of a way of funnelling all these pennies into
an account that I'll set up tomorrow?
--
For real reply address, lose the cash www.realuk.co.uk
"Jon Skeet [C# MVP]" <sk***@pobox.com> wrote in message
news:MP************************@msnews.microsoft.c om... Rob Oldfield <r$ob@oldfi$eld100.freese$rve.c$o.uk> wrote: I repeat. It's lunacy. It might be a good idea, but the fact is that NOBODY ACTUALLY DOES IT THIS WAY.
Well, that might be an exaggeration, but very few people.
I suspect that decimal is generally intended for financial applications, and given that the name is "banker's rounding" my guess is that it's not uncommon in that sector. I don't personally have a lot of experience with the financial sector - do you?
-- Jon Skeet - <sk***@pobox.com> http://www.pobox.com/~skeet If replying to the group, please do not mail me too
This isn't going to solve the problem for you, but it does provide
justification: http://tinyurl.com/vv4v
Colin
"Rob Oldfield" <r$ob@oldfi$eld100.freese$rve.c$o.uk> wrote in message
news:OD**************@TK2MSFTNGP12.phx.gbl... From the documentation about Decimal.Round....
"When d is exactly halfway between two rounded values, the result is the rounded value that has an even digit in the far right decimal position.
For example, when rounded to two decimals, the value 2.345 becomes 2.34 and
the value 2.355 becomes 2.36. This process is known as rounding toward even,
or rounding to nearest."
I'd have to disagree. I'd go for something more like "This process is
known is arbitrarily ignoring a de facto standard." Does anyone have a sensible method of returning the correct rounded value i.e. without resorting to decimal.round(x+0.00000001,2)
And has anyone got any justification for this ludicrousness?
-- For real reply address, lose the cash www.realuk.co.uk
Thanks for that. I get the justification and it does indeed make sense (in
much the same way that the optimal keyboard layout as opposed to QWERTY),
but the problem is if nobody in the real world actually uses it. As I've
said elsewhere in this thread, it may be that US bankers do, but UK ones
certainly don't.
I'd also say that it's not the way that the function works that is the
problem but, as Jon and William point out, that there isn't a sensibly
accessible method of choosing what method to use.
--
For real reply address, replace the _surprised_ bits with dots www.realuk.co.uk
"Colin Young" <x@nospam.com> wrote in message
news:ON**************@TK2MSFTNGP09.phx.gbl... This isn't going to solve the problem for you, but it does provide justification: http://tinyurl.com/vv4v
Colin
"Rob Oldfield" <r$ob@oldfi$eld100.freese$rve.c$o.uk> wrote in message news:OD**************@TK2MSFTNGP12.phx.gbl... From the documentation about Decimal.Round....
"When d is exactly halfway between two rounded values, the result is the rounded value that has an even digit in the far right decimal position. For example, when rounded to two decimals, the value 2.345 becomes 2.34 and the value 2.355 becomes 2.36. This process is known as rounding toward even, or rounding to nearest."
I'd have to disagree. I'd go for something more like "This process is known is arbitrarily ignoring a de facto standard." Does anyone have a
sensible method of returning the correct rounded value i.e. without resorting to decimal.round(x+0.00000001,2)
And has anyone got any justification for this ludicrousness?
-- For real reply address, lose the cash www.realuk.co.uk
"Rob Oldfield" <r$ob@oldfi$eld100.freese$rve.c$o.uk> wrote in message And has anyone got any justification for this ludicrousness?
It's not any more ludicrous than deciding that x.5 always rounds up when
it is in fact equally close to the value below it. In fact it is statistically
much
better to sometimes round up and sometimes round down in that case.
Both methods have their place.
I like Jon's idea. There should be an enumeration of rounding types.
-- Kevin Gale
I always found it VERY odd that Excel used Arithmetic rounding (.5 rounds
up), where as VBA (which is integrated into Excel), and therefore
VisualBasic 6, use Banker's rounding.
If you think Banker's rounding is "lunacy", then you probably have never
done any work in statistics. Using arithmetic rounding is asymmetric, and
can skew data. Very bad....
This page explains rounding and how Excel rounds in various cases. http://support.microsoft.com/default...b;EN-US;196652
Read down on the page, and it describes the reasoning. Here's an excerpt:
"When you add rounded values together, always rounding .5 in the same
direction results in a bias that grows with the more numbers you add
together. One way to minimize the bias is with banker's rounding.
Banker's rounding rounds .5 up sometimes and down sometimes. The convention
is to round to the nearest even number, so that both 1.5 and 2.5 round to 2,
and 3.5 and 4.5 both round to 4. Banker's rounding is symmetric."
In fact, in any statistics project I did in college, we were required to use
either Banker's rounding or Random rounding. I was annoyed to find that I
had to implement my own rounding function in Excel to do Banker's rounding.
Go figure.
--Matthew W. Jackson
For what it's worth, I never meant to imply that I thought the method of
banker's rounding was lunatic. What I _did_ mean was that Microsoft's
decision to arbitratily impose one method, and to choose a non-standard one,
was lunatic.
--
For real reply address, replace the _surprised_ bits with dots www.realuk.co.uk
"Matthew W. Jackson" <th********************@NOSPAM.NOSPAM> wrote in message
news:Oo**************@TK2MSFTNGP11.phx.gbl... I always found it VERY odd that Excel used Arithmetic rounding (.5 rounds up), where as VBA (which is integrated into Excel), and therefore VisualBasic 6, use Banker's rounding.
If you think Banker's rounding is "lunacy", then you probably have never done any work in statistics. Using arithmetic rounding is asymmetric, and can skew data. Very bad....
This page explains rounding and how Excel rounds in various cases. http://support.microsoft.com/default...b;EN-US;196652
Read down on the page, and it describes the reasoning. Here's an excerpt:
"When you add rounded values together, always rounding .5 in the same direction results in a bias that grows with the more numbers you add together. One way to minimize the bias is with banker's rounding.
Banker's rounding rounds .5 up sometimes and down sometimes. The
convention is to round to the nearest even number, so that both 1.5 and 2.5 round to
2, and 3.5 and 4.5 both round to 4. Banker's rounding is symmetric."
In fact, in any statistics project I did in college, we were required to
use either Banker's rounding or Random rounding. I was annoyed to find that I had to implement my own rounding function in Excel to do Banker's
rounding. Go figure.
--Matthew W. Jackson
Always rounding up may be ludicrous, but the point is that it's a standard
ludicrous.
--
For real reply address, replace the _surprised_ bits with dots www.realuk.co.uk
"Kevin Gale" <kg***@PLEASE-DELETEprintcafe.com> wrote in message
news:10*************@mail1.segnet.com... "Rob Oldfield" <r$ob@oldfi$eld100.freese$rve.c$o.uk> wrote in message And has anyone got any justification for this ludicrousness? It's not any more ludicrous than deciding that x.5 always rounds up when it is in fact equally close to the value below it. In fact it is
statistically much better to sometimes round up and sometimes round down in that case.
Both methods have their place. I like Jon's idea. There should be an enumeration of rounding types.
-- Kevin Gale
"Rob Oldfield" <rob@oldfield100_wow_freeserve_yikes_co_incredible !_uk> wrote in
message news:uV**************@TK2MSFTNGP11.phx.gbl... Always rounding up may be ludicrous, but the point is that it's a standard ludicrous.
Standard for who? Microsoft does it both ways in different products and Borland
uses banker's rounding in most of it's products but has a few exceptions. I'm
positive that a little research would come up the lots of products that do it
one way and lots the other. Seems like the problem is that there is no standard
(although I'm told that the IEEE 754 floating-point standard does specify
banker's rounding).
I agree with you in the sense that it should be a standard one way or the other.
Having it change from one product to another is just asking for trouble.
-- Kevin ### This discussion thread is closed Replies have been disabled for this discussion. ### Similar topics
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