Perhaps
superior but somewhat late--what would one do prior to
4.73.0?
-----Original
Message-----
From: amibroker@xxxxxxxxxxxxxxx
[mailto:amibroker@xxxxxxxxxxxxxxx]On Behalf
Of Tomasz Janeczko
Sent: Thursday, January 26, 2006 1:22
AM
To: amibroker@xxxxxxxxxxxxxxx
Subject: Re: [amibroker] Nearly Equal or
is it Fuzzy Math
AlmostEqual
function is superior solution.
Best
regards,
Tomasz Janeczko
amibroker.com
----- Original
Message -----
To: amibroker@xxxxxxxxxxxxxxx
Sent: Thursday, January
26, 2006 4:01 AM
Subject: RE: [amibroker]
Nearly Equal or is it Fuzzy Math
The
old saw is to always use >= or <=
with floats.
Bob
-----Original
Message-----
From: amibroker@xxxxxxxxxxxxxxx
[mailto:amibroker@xxxxxxxxxxxxxxx]On Behalf
Of Tomasz Janeczko
Sent: Tuesday, January 24, 2006 8:44
AM
To: amibroker@xxxxxxxxxxxxxxx
Subject: Re: [amibroker] Nearly Equal or
is it Fuzzy Math
AlmostEqual() - it is in the read
me.
AlmostEqual( x, y, ulps = 5
)
this is a helper function for comparing floating point numbers.It
returns True if x and y are equal or almost equal upto defined accurracy
(ulps).It is recommended to use this function instead of equality check (==)
as itleads to more reliable comparisons and less headache caused by IEEE
floating pointacurracy issues.
Parameters:x, y - the numbers or arrays
to be compared,Ulps stands for "units in last place" and represents maximum
relative error of the comparison. Since 32 bit IEEE floating point numbers
have accurracy of 7 significant digits, 1 unit in last place(ulp) represents
relative error of 0.00001 %. The default value of ulps parameter is 5 which
gives roughtly 0.00005% "comparison sensitivity".
Example
code:
if( 1/3 == 0.3333333 )
{
printf("32-bit Floating
point IEEE exact equality\n");
}
if( AlmostEqual( 1/3, 0.3333333 ) )
{
printf("Numbers are almost
equal\n");
}
HINT FOR THE FUTURE:
At any time if you forgot the name, just
type space and then press CTRL+SPACE keys in the AFL editor and you will see
the list of all keywords.
Best regards,
Tomasz
Janeczko
amibroker.com
----- Original
Message -----
To: amibroker@xxxxxxxxxxxxxxx
Sent: Tuesday, January
24, 2006 2:57 PM
Subject: [amibroker] Nearly
Equal or is it Fuzzy Math
I thought Tomasz had added a function
where one could compare two
numbers and get a TRUE indicator
even when the last bit of floating
point number did not
agree.
I've search the on list of functions
and can't seem to find that
function or a discussion out
it.
Anyone recall what that function is
called?
Thanks
Joe