v1.7.0

Breaking Changes

• Circuit : remove target_size in preparation for all contraction specifications to be encapsulated at the contract level (e.g. with cotengra)
• some TN drawing options (mainly arrow options) have changed due to the backend change detailed below.

Enhancements:

Multi tag drawing support:

• TensorNetwork.draw: use quimb.schematic for main backend="matplotlib" drawing. Enabling:
  1. multi tag coloring for single tensors
  2. arrows and labels on multi-edges
  3. better sizing of tensors using absolute units
  4. neater single tensor drawing, in 2D and 3D

• add quimb.schematic.Drawing from experimental submodule, add example docs at schematic. Add methods text_between, wedge, line_offset and other tweaks for future use by main TN drawing.

• upgrade all contraction to use cotengra as the backend
• Circuit : allow any gate to be controlled by any number of qubits.
• Circuit : support for parsing openqasm2 specifications now with custom and nested gate definitions etc.
• add is_cyclic_x, is_cyclic_y) and is_cyclic_z to TensorNetwork2D and TensorNetwork3D.
• add TensorNetwork.compress_all_1d for compressing generic tensor networks that you promise have a 1D topology, without casting as a TensorNetwork1D.
• add MatrixProductState.from_fill_fn for constructing MPS from a function that fills the tensors.
• add Tensor.idxmin and Tensor.idxmax for finding the index of the minimum / maximum element.
• 2D and 3D classical partition function TN builders: allow output indices.
• quimb.experimental.belief_propagation: add various 1-norm/2-norm dense/lazy BP algorithms.

Bug fixes:

• fixed bug where an output index could be removed by squeezing when performing tensor network simplifications.

• Fix deprecation warnings by @king-p3nguin in #209

New Contributors

• @king-p3nguin made their first contribution in #209

Full Changelog: v1.6.0...v1.7.0