Annotation of embedaddon/php/ext/bcmath/libbcmath/FAQ, revision 1.1
1.1 ! misho 1: BCMATH FAQ:
! 2:
! 3: 1) Why BCMATH?
! 4:
! 5: The math routines of GNU bc become more generally useful in a
! 6: library form. By separating the BCMATH library from GNU bc,
! 7: GNU bc can be under the GPL and BCMATH can be under the LGPL.
! 8:
! 9: 2) Why BCMATH when GMP exists?
! 10:
! 11: GMP has "integers" (no digits after a decimal), "rational numbers"
! 12: (stored as 2 integers) and "floats". None of these will correctly
! 13: represent a POSIX BC number. Floats are the closest, but will not
! 14: behave correctly for many computations. For example, BC numbers have
! 15: a "scale" that represent the number of digits to represent after the
! 16: decimal point. The multiplying two of these numbers requires one to
! 17: calculate an exact number of digits after the decimal point regardless
! 18: of the number of digits in the integer part. GMP floats have a
! 19: "fixed, but arbitrary" mantissa and so multiplying two floats will end
! 20: up dropping digits BC must calculate.
! 21:
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