BUILT-IN MATHEMATICA SYMBOL

Accuracy

Accuracy[x]
gives the effective number of digits to the right of the decimal point in the number x.

Accuracy[x] does not normally yield an integer result, and need not be positive.

For any approximate number x, Accuracy[x] is equal to Precision[x]-RealExponent[x].

For machine-precision numbers, Accuracy[x] gives the same as $MachinePrecision-Log[10, Abs[x]]. »

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

Machine-precision number:

Arbitrary-precision number:

Exact number:

Machine-precision number:

Out[1]=

Arbitrary-precision number:

Out[1]=

Exact number:

Out[1]=

Accuracy is the effective number of digits known to the right of the decimal point:

A zero known to accuracy 20:

The precision of

is the same as the accuracy of

:

Accuracy of a machine zero:

The uncertainty

is effectively the smallest positive machine number:

Specify accuracy as the goal for N:

The accuracy of a symbolic expression is the minimum of the accuracies of its numbers:

Check the quality of a result:

Track loss of accuracy in a repetitive calculation:

For machine-precision numbers, Accuracy[x] is the same as $MachinePrecision-Log[10, Abs[x]]:

For non-machine numbers, Precision[x]==RealExponent[x]+Accuracy[x]:

Accuracy and Precision in iterating the logistic map: