AFL Function Reference

Math functions
(AmiBroker 4.80)

SYNTAX	AlmostEqual( x, y, ulps = 5 )
RETURNS	NUMBER ARRAY
FUNCTION	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 it leads 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". Thanks to Bruce Dawson for his fast routine.
EXAMPLE	`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"); }`
SEE ALSO

The AlmostEqual function is used in the following formulas in AFL on-line library: