|
Herman,
This is NOT overflow !
Overflow in single precision number happens when
number is greater than 3.4×1038
That is:
3800000000000000000000000000000000000000
This is the largest number that 32 bit standard
IEEE can handle.
Overflow would happen when number exeeded
that.
The other thing is number of *significant
digits*.
This is how many digits are actually 100%
accurrate - that's 7+ digits.
MUST READ:
What is significant digit:
Users' Guide:
BTW: IEEE 32 bit standard is a world-wide standard
for floating point arithmetic
available in ALL computer languages (in C it is
represented by 'float' type).
What's more it is used in TradeStation, Wealth-Lab,
Metastock and other trading apps
and you would get the same results there as
well.
Best
regards,
Tomasz Janeczko
amibroker.com
----- Original Message -----
Sent: Monday, May 14, 2007 5:47 AM
Subject: Re: [amibroker] Amibroker
calculation error
You are exceeding the digit limit for AmiBroker. Do a search for
"precision", its been discussed many times but I have forgotten the details..
7 digits is the limit I seem to recall.
AmiBroker doesn't have an overflow error msg.
herman
Monday, May 14, 2007, 11:06:47 AM, you wrote:
|
> |
Herman:
My concern is not getting the date format right.
There are many ways to do that.
I just need to understand why this simple
calculation (add) can have error.
1070511 + 19000000 = 20070512 instead of
20070511.
My hope is that somebody (maybe TJ) can explain it
to me.
This is something serious, because it affects my
confidence level toward Amibroker as a whole.
Thanks,
- Mark
From: amibroker@xxxxxxxxxxxxxxx
[mailto:amibroker@xxxxxxxxxxxxxxx] On
Behalf Of Herman
Sent: Sunday, May
13, 2007 10:41 PM
To: Mark
H
Subject: Re:
[amibroker] Amibroker calculation error
|
Why not use this:
Filter = 1;
SetOption("NoDefaultcolumns",False);
DateNumber
= ParamDate("Date",Now(1)); // To provice test
DateNum
DateString
= NumToStr(DateTimeConvert( 2,
DateNumber),formatDateTime);
AddTextColumn(DateString, "DateNum");
Buy = 1;
herman
Monday, May 14, 2007, 10:23:37 AM, you
wrote:
|
> |
I am trying to convert a date number
to a year+month+day number for better display.
It worked before, but for May 11, I
got this error:
1070511 + 19000000 = 20070512 instead
of 20070511.
Here is a piece of code to demonstrate
this calculation error:
---------------------------------------------------------
filter = 1;
daten
= StrFormat("%f", 1070511 + 19000000);
AddTextColumn(daten, "DateNum");
buy = 1;
---------------------------------------------------------
The column will display
20070512.00000, not 20070511 as you would expect.
I understand that in AFL, all numbers
are in double type and integer is converted when used.
However, this doesn?t seem to be a rounding error since the
result is exactly 20070512.00000, not something like
20070511.71332.
I am using 4.90.5.
Have anyone seen this
before?
Thanks,
- Mark
|
| |
__._,_.___
Please note that this group is for discussion between users only.
To get support from AmiBroker please send an e-mail directly to
SUPPORT {at} amibroker.com
For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
http://www.amibroker.com/devlog/
For other support material please check also:
http://www.amibroker.com/support.html
![]()
SPONSORED LINKS
__,_._,___
|