--- a/CONTRIBUTORS Mon Mar 25 10:16:14 2024 +0100
+++ b/CONTRIBUTORS Mon Mar 25 14:08:25 2024 +0100
@@ -12,6 +12,10 @@
* March 2024: Anthony Bordg, Manuel Eberl, Wenda Li, Larry Paulson
New and more general definition of meromorphicity in HOL-Complex_Analysis
+* Feb/March 2024: Jonas Stahl
+ Automatic translation of HOL functions into corresponding
+ step-counting running-time functions
+
* 2023/2024: Makarius Wenzel and Fabian Huch
More robust and scalable support for distributed build clusters.
--- a/NEWS Mon Mar 25 10:16:14 2024 +0100
+++ b/NEWS Mon Mar 25 14:08:25 2024 +0100
@@ -52,6 +52,9 @@
"preplay_timeout". INCOMPATIBILITY.
- Added the action "order" testing the proof method of the same name.
+* Session Data_Structures provides automatic translation from
+HOL functions into corresponding step-counting running-time functions.See theory Define_Time_Function.
+
* Explicit type class for discrete_linear_ordered_semidom for integral
semidomains with a discrete linear order.
--- a/src/HOL/Data_Structures/Define_Time_Function.thy Mon Mar 25 10:16:14 2024 +0100
+++ b/src/HOL/Data_Structures/Define_Time_Function.thy Mon Mar 25 14:08:25 2024 +0100
@@ -1,9 +1,10 @@
(*
Author: Jonas Stahl
-Automatic definition of running time functions from HOL functions
+Automatic definition of step-counting running-time functions from HOL functions
following the translation described in Section 1.5, Running Time, of the book
Functional Data Structures and Algorithms. A Proof Assistant Approach.
+See https://functional-algorithms-verified.org
*)
theory Define_Time_Function
@@ -20,17 +21,33 @@
declare [[time_prefix = "T_"]]
-text \<open>The pre-defined functions below are assumed to have constant running time.
+text \<open>
+This theory provides commands for the automatic definition of step-counting running-time functions
+from HOL functions following the translation described in Section 1.5, Running Time, of the book
+"Functional Data Structures and Algorithms. A Proof Assistant Approach."
+See @{url "https://functional-algorithms-verified.org"}
+
+Command \<open>time_fun f\<close> retrieves the definition of \<open>f\<close> and defines a corresponding step-counting
+running-time function \<open>T_f\<close>. For all auxiliary functions used by \<open>f\<close> (excluding constructors),
+running time functions must already have been defined.
+If the definition of the function requires a manual termination proof,
+use \<open>time_function\<close> accompanied by a \<open>termination\<close> command.
+Limitation: The commands do not work properly in locales yet.
+
+The pre-defined functions below are assumed to have constant running time.
In fact, we make that constant 0.
This does not change the asymptotic running time of user-defined functions using the
pre-defined functions because 1 is added for every user-defined function call.
-Note: Many of the functions below are polymorphic and reside in type classes.
+Many of the functions below are polymorphic and reside in type classes.
The constant-time assumption is justified only for those types where the hardware offers
suitable support, e.g. numeric types. The argument size is implicitly bounded, too.
The constant-time assumption for \<open>(=)\<close> is justified for recursive data types such as lists and trees
-as long as the comparison is of the form \<open>t = c\<close> where \<open>c\<close> is a constant term, for example \<open>xs = []\<close>.\<close>
+as long as the comparison is of the form \<open>t = c\<close> where \<open>c\<close> is a constant term, for example \<open>xs = []\<close>.
+
+Users of this running time framework need to ensure that 0-time functions are used only
+within the above restrictions.\<close>
time_fun_0 "(+)"
time_fun_0 "(-)"