Miscellaneous Information

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Please let us know if there is other information that you would find of use in this guide.


If you are having problems using the `make' utility, be sure that you are using GNU make. We have seen problems with Version 3.81 of that utility, so if you encounter errors, please consider our instructions for downloading and installing GNU make version 3.80.

Building ACL2 with SBCL may require the use of --dynamic-space-size. This is explained in the section on Obtaining SBCL.

Reasoning about the Real Numbers

ACL2 supports rational numbers but not real numbers. However, starting with Version 2.5, a variant of ACL2 called "ACL2(r)" supports the real numbers by way of non-standard analysis. ACL2(r) was conceived and first implemented by Ruben Gamboa in his Ph.D. dissertation work, supervised by Bob Boyer with active participation by Matt Kaufmann. See the documentation topic REAL for information about this extension and how to build it, and a warning about its experimental nature.

If you care to use ACL2(r), you will need to build an executable image and you will probably want to certify books. First, connect to your new dir/acl2-8.5/ directory and execute

make large-acl2r LISP=xxx

where xxx is the command to run your local Common Lisp.

By default, if no LISP=xxx is specified, LISP=ccl is used. On our hosts, ccl is the name of Clozure Common Lisp (CCL), which can be obtained as explained in the Requirements document.

This will create executable saved_acl2r in the dir/acl2-8.5 directory (notice the final letter r in the executable filename).

Finally, you can certify books under directory dir/acl2-8.5/books/nonstd/ with ACL2(r) in the usual way; for example, see the documentation topic for BOOKS-CERTIFICATION.

Links and Mailing Lists

There are several mailing lists for ACL2 users. You can post messages to these lists only if you are a member. You may subscribe to or unsubscribe from these lists, or view their archives, at:

Finally, please report bugs in ACL2 to Matt Kaufmann.

Export/Re-Export Limitations

ACL2 may be exported to any countries except those subject to embargoes under various laws administered by the Office of Foreign Assets Control ("OFAC") of the U. S. Department of the Treasury.

License and Copyright

ACL2 Version 8.5 -- A Computational Logic for Applicative Common Lisp
Copyright (C) 2022, Regents of the University of Texas

This version of ACL2 is a descendent of ACL2 Version 1.9, Copyright (C) 1997 Computational Logic, Inc.

This program is free software; you can redistribute it and/or modify it under the terms of the LICENSE file distributed with ACL2.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the LICENSE for more details.

Matt Kaufmann (Kaufmann@cs.utexas.edu)
J Strother Moore (Moore@cs.utexas.edu)

Department of Computer Sciences
University of Texas at Austin
Austin, TX 78712-1188 U.S.A.

For more information on copyright, licensing, and authorship, see the documentation topic, COPYRIGHT.

Although releases are best obtained according to the installation instructions by fetching a gzipped tar file from GitHub containing ACL2 Version 8.5 and the corresponding Community Books, here we note that the git commit hash for Version 8.5 of ACL2 on github is:


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