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