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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 -----
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
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