1BCMATH FAQ: 2 31) Why BCMATH? 4 5The math routines of GNU bc become more generally useful in a 6library form. By separating the BCMATH library from GNU bc, 7GNU bc can be under the GPL and BCMATH can be under the LGPL. 8 92) Why BCMATH when GMP exists? 10 11GMP has "integers" (no digits after a decimal), "rational numbers" 12(stored as 2 integers) and "floats". None of these will correctly 13represent a POSIX BC number. Floats are the closest, but will not 14behave correctly for many computations. For example, BC numbers have 15a "scale" that represent the number of digits to represent after the 16decimal point. The multiplying two of these numbers requires one to 17calculate an exact number of digits after the decimal point regardless 18of the number of digits in the integer part. GMP floats have a 19"fixed, but arbitrary" mantissa and so multiplying two floats will end 20up dropping digits BC must calculate. 21 22
