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ANN - Artificial Neural Network for PHP

This project realizes a neural network topology called multilayer perceptron for PHP environments. The source code is based on a work by Eddy Young in 2002. Several improvements and changes on this implementation are done by Thomas Wien (thwien.de - Germany) since 2007. You will find the PHP source in the section Download. Please, consider the Copyright. To get a short idea what is the benefit of neural networks have a look at page Neural Networks.

Project backgroud

Since 1992 I was fascinated about the functionality of neural networks like multilayer perceptron. In the past I planned to realize and use neural networks in PHP projects. Since take-over Eddy's project in 2007 and the release of version 2.3.0 in 2012 many things have changed in using neural networks.

Today it is common to use large language models. Therefore I think there is no need anymore for a PHP class to implement a multilayer perceptron. But large language models based on multilayer perceptron. Nevertheless this PHP class can help to understand the core basics of modern neural networks. So, this PHP class can be part of training or learning fundamental concepts. Enjoy!

Overview

• Neural Networks
• Multilayer Perceptron
• Download
• Installation
• Examples
• FAQ
• Copyright

Versions and Change-Log

Version 3.0.0 by Thomas Wien (2025-10-04) Download

* Full rework of all PHP scripts
* Remaining functioniality reduced to fundamentaly function of neural network only
* Phar support removed
* PHP 8.2 is required

Version 2.3.0 by Thomas Wien (2012-12-13)

• Using traits for performance reasons
• Checking php version for compatibility with ANN library
• PHP 5.4.x or above

Version 2.2.3 by Thomas Wien (2012-12-12)

• Bugfix: Division by zero if training time below one second
• Adding php version and sapi interface to network information
• Test running on PHP 5.4

Version 2.2.2 by Thomas Wien (2011-07-04)

• Redesign of network details
• Considering cpu limits for calculation of network execution time

Version 2.2.1 by Thomas Wien (2011-06-15)

• Bug fix: Wrong output type detection in binary networks
• Using Interface called \ANN\InterfaceLoadable to make easier decision of loadable objects.

Version 2.2.0 by Thomas Wien (2011-06-01)

• Introduction of namespaces as of PHP 5.3
• Dynamic learning rate
• \ANN\Network::setLearningRate() is protected now
• Bug fix: Wrong output type detection in some circumstances

Version 2.1.7 by Thomas Wien (2011-06-15)

• Bug fix: Wrong output type detection in binary networks

Version 2.1.6 by Thomas Wien (2011-06-01)

• Bug fix: Wrong output type detection in some circumstances

Version 2.1.5 by Thomas Wien (2011-05-24)

• Dividing method ANN_Math::random() in ANN_Math::randomDelta() and ANN_Math::randomWeight()
• Better implementation of printing network details including __invoke() und __toString() converting

Version 2.1.4 by Thomas Wien (2011-05-23)

• Better calculation of remaining time of running the network
• Fixing bug: generating random delta not correct
• Adding momentum value
• Simplified ANN_Neuron::adjustWeights()
• Remove possible wrong calculation in ANN_Neuron::adjustWeights() on linear networks
• Simplify ANN_Layer::calculateHiddenDeltas()

Version 2.1.3 by Thomas Wien (2010-01-06)

• Date input support class

Version 2.1.2 by Thomas Wien (2009-12-26)

• Classification support
• Phar support (as of PHP 5.3.0)

Version 2.1.1 by Thomas Wien (2009-12-23)

• String association support

Version 2.1.0 by Thomas Wien (2009-12-22)

• Checking parameter counts on ANN_Values::input() and ANN_Values::output()
• Removing protected method ANN_Neuron::getInputs()
• Fixing bug: Error tolerance calculation in ANN_Network::isTrainingComplete()
• Switching to Git version control
• Moving all experimental code into branch
• Removing all experimental code from master branch (due to performance and future development)

Version 2.0.7 by Thomas Wien (2009-01-01) Download

• Removing protected method ANN_Neuron::setOutput()
• Removing protected unused method ANN_Layer::getInputs()
• Removing protected unused property ANN_Layer::$arrInputs
• More detailed exceptions to ANN_Filesystem::saveToFile()
• Different distribution of activation calls across the layers
• Different adjustments in ANN_Neuron::adjustWeights() depending on output type
• Removing static local variables from ANN_Network::getNextIndexInputsToTrain()
• Increasing math precision
• Using class constants for output types (increasing performance)
• Fixing bug: ANN_Neuron::getOutput() is float and not array

Version 2.0.6 by Thomas Wien (2008-12-18)

• Printing network details of output differences to their desired values
• Complete rewritten code standard of variables
• New class ANN_Values for defining input and output values
• Code examples to phpdoc
• Internal math precision defaults to 5

Version 2.0.5 by Thomas Wien (2008-12-16)

• Adjustable output error tolerance between 0 and 10 per cent
• Internal rounding of floats for performance issues
• Loading class for all ANN classes (SPL autoload)
• Renaming filename of ANN_Maths class
• Improving code standard
• Fixing bug: Comparison in ANN_InputValue and ANN_OutputValue

Version 2.0.4 by Thomas Wien (2008-01-27)

• Weight decay
• QuickProp algorithm (experimental)
• RProp algorithm (experimental)
• Linear saturated activation function (experimental)
• Individual learning rate algorithm (experimental)
• Reducing of overfitting (no training if input pattern produces desired output)
• Increasing performance on activation
• Increasing performance on testing all patterns to their desired outputs
• Increasing performance on calculating hidden deltas
• Increasing performance by defining layer relation by construction
• More details to printNetwork()
• Fixing bug: learning rate is not part of saved delta value

Version 2.0.3 by Thomas Wien (2008-01-17)

• Support for dynamic learning rate
• Automatic epoch determination
• Automatic output type detection
• Shuffling input patterns each epoch instead of randomized pattern access
• Logging of network errors
• Logging on each epoch instead of each training step
• Avoiding distributed internal calls of setMomentum() and setLearningRate()
• Extending display of network details
• Fixing bug: runtime error on call of setMomentum()

Version 2.0.2 by Thomas Wien (2008-01-14)

• Client-Server model for distributed applications
• Calculating total network error for csv logging

Version 2.0.1 by Thomas Wien (2008-01-06)

• Separation of classes to several files
• Version control by Subversion
• Performance issues
• Graphical output of neural network topology
• Logging of weights to csv file

Version 2.0.0 by Thomas Wien (2007-12-17)

• PHP 5.x support
• PHPDoc documentation
• Momentum support
• Avoiding network overfitting
• Linear / binary output
• ANN_InputValue + ANN_OutputValue classes
• Exceptions
• Threshold function
• Hyperbolic tangent transfer function
• Several performance issues
• Avoiding array_keys() & srand() due to performance
• Changes in saving and loading network
• Printing network details to browser
• Fixing bug: initializing inputs to all hidden layers
• Fixing bug: training for first hidden layer was skipped

Version 1.0 by Eddy Young (2002)

• Initial version