Precision

Usage

• Precision[x] gives the effective number of digits of precision in the number x.

Notes

• Precision[x] gives a measure of the relative uncertainty in the value of x.

• With absolute uncertainty dx, Precision[x] is -Log[10, dx/x].

• For exact numbers such as integers, Precision[x] is Infinity.

• Precision[x] does not normally yield an integer result.

• For machine-precision numbers Precision[x] yields MachinePrecision.

• Numbers entered in the form digits`p are taken to have precision p.

• Numbers such as 0``a whose overall scale cannot be determined are treated as having zero precision.

• Numbers with zero precision are output in StandardForm as

, where

is their accuracy.

• If x is not a number, Precision[x] gives the minimum value of Precision for all the numbers that appear in x.

• New in Version 1; modified in 5.