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Diffstat (limited to 'ext/bcmath/libbcmath/FAQ')
| -rw-r--r-- | ext/bcmath/libbcmath/FAQ | 21 |
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diff --git a/ext/bcmath/libbcmath/FAQ b/ext/bcmath/libbcmath/FAQ new file mode 100644 index 0000000..6499b1c --- /dev/null +++ b/ext/bcmath/libbcmath/FAQ @@ -0,0 +1,21 @@ +BCMATH FAQ: + +1) Why BCMATH? + +The math routines of GNU bc become more generally useful in a +library form. By separating the BCMATH library from GNU bc, +GNU bc can be under the GPL and BCMATH can be under the LGPL. + +2) Why BCMATH when GMP exists? + +GMP has "integers" (no digits after a decimal), "rational numbers" +(stored as 2 integers) and "floats". None of these will correctly +represent a POSIX BC number. Floats are the closest, but will not +behave correctly for many computations. For example, BC numbers have +a "scale" that represent the number of digits to represent after the +decimal point. The multiplying two of these numbers requires one to +calculate an exact number of digits after the decimal point regardless +of the number of digits in the integer part. GMP floats have a +"fixed, but arbitrary" mantissa and so multiplying two floats will end +up dropping digits BC must calculate. + |