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Download version 1.0 [ Details], released 24 July 2005.

PyDaylight 1.0 supports Daylight toolkits v4.81 and newer. If you are using an older toolkit version you should try one of the older PyDaylight distributions.

PyDaylight is a rapid application development library based on the Daylight chemical informatics toolkits (http://www.daylight.com/). Researchers enjoy it because it lets them implement and test new chemical algorithms in less than half the time of traditional methods. Software developers appreciate the use of high-level constructs such as object-oriented design, iterators and exceptions, and the easy integration with other Python libraries. Support staff enjoy it for its readability and its robust implementation that precludes most categories of silent errors, including type mismatches and memory leaks.

See the MUG 2000 presentation about PyDaylight for many examples of what it can do and why you should use it.

Technical Features

  • Toolkit objects - including molecules, fingerprints, reactions and SMARTS and SMIRK queries - are first class Python objects with methods and attributes.
  • Full support for Thor and Merlin databases, including an MCL to PyDaylight compiler.
  • Depictions rendered in Tk and PIL, the Python Imaging Library.
  • Client and server libraries for program objects.
  • Toolkit streams and sequences are converted to native Python lists and iterators.
  • Function calls are checked and any error return values are converted to Python exceptions.
  • Automatic garbage collection.

Development and Support

PyDaylight is developed and maintained by Dalke Scientific Software, LLC. In partnership with Mesa Analytics and Computing, LLC we provide consulting, customization, support and training for PyDaylight and chemical informatics. For more information, please visit our services page or send email to info@dalkescientific.com.


Additional information about PyDaylight can be found at the following locations:
  • pydaylight-general@lists.sourceforge.net is the general discussion and announcement mailing list. Subscription details and the archive is available at its Mailman listinfo page.

  • The January 2001 edition of Dr. Dobb's Journal includes an article about PyDaylight. It goes into details about the Python to C integration.

  • PyDaylight was presented at two of the Daylight User Group Meetings:
    • MUG 2000: A high-level description of PyDaylight with many examples of how to use it.
    • MUG 1999: Describes more of the implementation details.

  • A presentation made at Daylight after adding Thor and Merlin support. Also available in tar.gz format.


SourceForge Logo PyDaylight development is hosted by Sourceforge. Developer information is available from its project page.

Download PyDaylight 1.0. [Details]

To access the source code through anonymous CVS you can run the following two lines. (When prompted for a password for anonymous, simply press the Enter key.)

PyDaylight CVS on Sourceforge

PyDaylight uses the standard Python installer. To install PyDaylight, download the package and move into the top-level directory then run the following from the shell.

% python setup.py install
You may need to be root to install in the default location. For more details see the README file. Please send any questions to the mailing list.

"Daylight", "Daylight toolkit", "Thor" and "Merlin" are registered trademarks of Daylight Chemical Information Systems, Inc. Daylight C.I.S. is neither affiliated with nor responsible for PyDaylight.

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