v2.0.0 release

Changed

• Made NengoSPA available under the GPLv2 license. (#295)

v1.3.0 release

1.3.0 (November 30, 2021)

Added

• Support for (fractional) binding powers and the notion of signs in algebras and for SemanticPointer instances. (#271, #286)
• EquallySpacedPositiveUnitaryHrrVectors and VectorsWithProperties vector generators. (#284, #285)
• Example of how to use learning connections between State modules. (#16, #288)

Removed

• Python 3.5 support was removed. (#273, #274)

Fixed

• Scalar arrays like np.array(1) will now be treated as scalars as intended. (#289)

v1.2.0 release

Added

• Transposed Vector-derived Transformation Binding (TVTB) algebra which has essentially the same properties as the existing VTB algebra, but has two-sided identities and inverses (opposed to VTB where these are right-sided only). The only difference in the math is that TVTB transposes the matrix used in the binding operation. (#266)
• Differentiation between left, right, and two-sided special elements (identity, zero, absorbing element, inverse) of an algebra. (#265)
• Added linv and rinv methods to SemanticPointer for the left and right inverse, respectively. (#265)
• Add support for the normalized and unitary methods on Semantic Pointer symbols. (#265)

Changed

• Creating special elements (identity, zero, absorbing element, inverse) of the VtbAlgebra without sidedness argument has been deprecated because these are only right-sided special element. Add the sidedness=ElementSidedness.RIGHT argument to update your code. (#265)
• The ~ operator has been deprecated for the VtbAlgebra. Use the rinv() method instead. (#265)
• Improved automatic names for SemanticPointer that only contain parenthesis where actually needed. In addition, syntax is considered when shortening a name exceeding the maximum length. (#255, #270)

v1.1.1 release

Fixed

• PointerSymbol precedence handling has been fixed. For example, (sym.A + sym.B) * sym.C will be evaluated correctly now. (#267, #268)

v1.1.0 release

Added

• Support division with constant scalars. (#249, #253, #257)

Changed

• Make AbstractAlgebra an actual abstract base class (using ABCMeta as meta-class). While still supported, this deprecates pure duck-typing for algebras. (#240)
• Raise an exception when a Semantic Pointer is added to a vocabulary with a differing algebra. (#239, #240)
• All examples now have seeds to ensure that occasional "bad seeds" do not create problems in the documentation. (#248)

Fixed

• SemanticPointer.translate and PointerSymbol.translate now use the keys argument; previously, this argument was mistakenly ignored. (#248)
• Fixed an issue where the names of iteratively generated semantic pointers could grow exponentially in length, by truncating them at 1 KB. (#244, #246)
• Allow NumPy scalars in place of Python scalars for binary operations on SemanticPointer instances. (#250, #257)
• The SPA sequence example was not working properly due to a missing connection. (#258, #259)

v1.0.1 release

Changed

• Add redirects from old URLs to documentation. (#237, #238)

v1.0.0 release

Changed

• Ensure compatibility with Nengo 3. (#225, #233, #236)
• Modules and networks no longer set a default label. This will give more useful labels by default in Nengo GUI (assuming the latest dev version). (#234, #235)
• All networks have been converted to classes. This will give more useful labels by default in Nengo GUI (assuming the latest dev version). (#234, #235)

Removed

• Dropped support for Python 2.7 and 3.4. (#233, #236)

v0.6.2 release

Added

• Add previously missing documentation on the vector_generation module as well as the reinterpret and translate methods of SemanticPointer. (#228, #229)

Fixed

• Fixed a bug where an exception within an ActionSelection block would lead to every subsequent ActionSelection block to raise an exception. (#230, #231)
• Nengo SPA is now compatible with pytest 4. Support for earlier versions has been dropped. (#227)

v0.6.1 release

Changed

• Minor documentation improvements. (#217, #218)

v0.6.0 release

Added

• Support for algebras that allow to use binding operations other than circular convolution. This includes an implementation of vector-derived transformation binding (VTB) and the nengo_spa.networks.VTB network to perform this particular binding operation. (#69, #198)
• Added generators for vectors with different properties that can be used to define how vectors are created in a vocabulary (e.g., axis-aligned, orthogonal, unitary). (#201, #129)
• Added a matrix multiplication network nengo_spa.networks.MatrixMult based on the nengo-extras implementation. (#198)
• Allow to connect to the utility node returned by ifmax with the SPA >> operator. (#190, #194)
• The Semantic Pointer names AbsorbingElement, Identity, and Zero now have a special meaning in Vocabulary and nengo_spa.sym and will return the respective special Semantic Pointers. (#195, #176)
• SemanticPointer instance can now track names for improved labeling in Nengo GUI. (#202, #184)
• Label the utility nodes for the action selection. (#202)

Changed

• A number of module names have been changed for better naming consistency. In particular,

  • nengo_spa.actions to nengo_spa.action_selection,
  • nengo_spa.pointer to nengo_spa.semantic_pointer,
  • nengo_spa.vocab to nengo_spa.vocabulary,
  • and nengo_spa.modules.assoc_mem to nengo_spa.modules.associative_memory.

  (#199, #205)

• Require the mapping argument for associative memories. In addition to dictionaries and the string 'by-key', a sequence of strings can be passed in to create an auto-associative memory. (#177)

• Changed the rng argument for Vocabulary to pointer_gen. (#201)

• Renamed input_a and input_b of the nengo_spa.Bind module to input_left and input_right to account for non-commutative binding methods where the order of operands matters. Also, renamed the invert_a and invert_b arguments to unbind_left and unbind_right to reflect that some binding methods might not have inverse vectors, but might still be able to do unbinding. (#69, #198)

• Renamed the nengo_spa.State parameter represent_identity to represent_cc_identity to reflect that it only optimizes for the circular convolution identity, but not the identity for other binding operations. (#212)

Removed

• Removed nengo_spa.networks.circularconvolution.circconv because nengo_spa.algebras.CircularConvolutionAlgebra provides the same functionality. (#198)
• The SemanticPointer class does no longer accept a single integer as dimensionality to create a random vector. Use the new generators in nengo_spa.vector_generation instead. (#201)

Fixed

• Raise an exception instead of returning incorrect results from prob_cleanup. Also, fix the function's incorrect documentation. (#203, #206)
• Fix nengo_spa.ActionSelection.keys() when no named actions have been provided. (#210)
• Do not create an unnecessary compare network when computing a dot product with a SemanticPointer instance. (#202)
• Handle SemanticPointer instances correctly as first argument to nengo_spa.dot. (#202)