theory Timing

imports "../Base"

begin

section {* Measuring the Time of an Operation\label{rec:timing} *} 

text {*

 {\bf Problem:}

  You want to measure the running time of a tactic or function.\smallskip

  {\bf Solution:} Time can be measured using the function 

  @{ML start_timing} and @{ML end_timing}.\smallskip

*}

ML{*fun ackermann (0, n) = n + 1

  | ackermann (m, 0) = ackermann (m - 1, 1)

  | ackermann (m, n) = ackermann (m - 1, ackermann (m, n - 1)) *}

ML {*

let

  val start = start_timing ()

  val res = ackermann (3,12)

  val time = (end_timing start)

in

 (res,time)

end

*}

text {*

  check what @{text "#all"} does?

*}

end