Downloading papers, reports, presentations, and executables

• Gzip-compressed (.gzip)
• Postscript (.ps)
• Portable document format (.pdf)

Paper copies of any materials linked to the AMPL site are also available by request to info@ampl.com.

To save disk space and speed transmission, some of the longer files at this site have been compressed by gzip. These include postscript-format files for papers, reports and presentations, as well as executable files from netlib/ampl. All gzip-compressed files have names that end in ".gz".

Under some combinations of web browser and operating system, decompression is performed automatically whenever you click on a link to a gzip-compressed file. If you have this feature, compressed files will be handled correctly without any effort on your part; you need not even be aware that they are different from other files.

If compressed files fail to be decompressed or handled properly, then you may be able to fix the problem by adjusting your web browser's "helper" configuration for the .gz suffix. Many browser versions are hard to configure for this purpose, however, or mishandle gzip-compressed files. (For more information, see netlib's discussion under the heading, What do these .gz suffixes mean? -- especially the last couple of paragraphs.)

If necessary, you can fall back on manual decompression. First, instruct your browser to save the file to your disk, rather than view it. (Procedures for this operation vary from one browser to another.) The saved file's name should end in .gz; if not, try using it, to check whether it has already been decompressed, and add .gz to its name if it hasn't been. Then apply decompression directly to the file:

• Under Unix, run the gzip program by giving a command of the form "gzip -d filename" or "gunzip filename". Most Unix systems have gzip installed; if yours doesn't, you can download source code, or binaries for most of the computers on which AMPL runs, from the gzip home page.

• Under Windows, apply a file conversion or decompression utility. Some utilities can be set up to automatically decompress a file ending in .gz when you double-click on the file's icon, or can be opened as a window to which you can drag and drop file icons; see your utility's instructions for details. If your computer doesn't have an appropriate conversion or decompression utility installed, you can download Aladdin Expander free of charge.

If you get an error message to the effect that the file is not in gzip format, it is possible that your browser did decompress it but left the suffix .gz on the filename. To test for this possibility, simply remove the .gz from the name and try using the file.

Many reports and presentations available from this site are provided in postscript format. All postscript files have names that end in ".ps" if uncompressed, or in ".ps.gz" if they have also been gzip-compressed.

Under some combinations of web browser and operating system, postscript files are automatically decompressed (if necessary) and sent to a postscript-viewing application whenever you click on a link to a postscript format file. If you have this feature, postscript files will display correctly without any special effort on your part. The application for viewing them may also be used to print them.

If postscript files fail to display readably, or do not display at all, you may be able to fix the problem by adjusting your web browser's "helper" configuration for the .ps suffix. Check first that you have a postscript viewer installed for the computer you're using, though. If you don't, you may be still be able to save postscript files to your disk and then print them (after decompressing them, if necessary). Instructions for all of these alternatives vary considerably from one platform to another, so it's best to ask for help locally.

Before you go to a lot of trouble to get your system set up for postscript viewing, consider relying on PDF format instead. It is usually much more convenient and flexible.

Many reports and presentations available from this site are provided in portable document format (or PDF) as an alternative to postscript. All PDF files have names that end in ".pdf".

Adobe Systems' Acrobat Reader program provides facilities for viewing and printing PDF files. You can download it free of charge for nearly all of the platforms on which AMPL runs; instructions for downloading and installation are provided at the Acrobat Reader download page. Once you have it installed, you should also install the Acrobat Reader "plugin" for your browser, which involves little more than copying a certain file to your browser's plugin directory. When you subsequently click on a PDF file, Acrobat Reader will display the document's first page immediately inside your browser window, along with controls for paging through it and for printing it.

Where available, PDF format is much preferable to postscript format. Acrobat Reader is more convenient to install and use than postscript viewers. It handles decompression of PDF files automatically, lets you search for text, and lets you copy selected text for pasting into other applications.

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