Skip to content

Timing

Status: Stable

documented, exercised by the test suite and/or worked examples, with no known limitations recorded.

Description

Timing[expr] evaluates expr, and returns a list of the time in seconds used, together with the result obtained.

Examples

No verified examples yet for this function.

Implementation notes

builtin_timing brackets a single evaluate(arg) call with clock() (CPU time, CLOCKS_PER_SEC) and returns {seconds, result} as a two-element List, where seconds is (end - start)/CLOCKS_PER_SEC as an EXPR_REAL. It measures processor time, not wall-clock, and times a single evaluation only. (Note: the argument is evaluated explicitly inside the builtin; Timing is not given Hold attributes here.)

  • HoldAll, Protected, SequenceHold.
  • Returns {timing, result}.
  • Includes only CPU time spent evaluating the expression.

Attributes: HoldAll, Protected, SequenceHold.

Implementation status

Stable — documented, exercised by the test suite and/or worked examples, with no known limitations recorded.

References

Notes & additional examples

Worked examples

In[1]:= Timing[Sum[i, {i, 1000}]]
Out[1]= {0.000244, 500500}

The timing is non-deterministic, so extract the reproducible result with Part:

In[1]:= Timing[Sum[i, {i, 1, 1000000}]][[2]]
Out[1]= 500000500000

In[1]:= Timing[D[Tan[x]^10, x]][[2]]
Out[1]= 10 Sec[x]^2 Tan[x]^9

Notes

Timing returns {seconds, result}. The first element is the CPU time spent and varies between runs and machines; only the second element (the computed result) is reproducible.