Release 0.9.0: major internal improvements, architecture system, and pass management

Added

• architecture system: platform and compilation strategy defaults are now built into OpenQL, preventing the need for users to copypaste configuration files from the tests directory
• interface (C++ and Python) to compile cQASM 1.x
• allow 'wait' and 'barrier' in JSON section 'gate_decomposition'
• CC backend:
  • improved reporting on JSON semantic errors
  • added check for dimension of "instruments/qubits" against "instruments/ref_control_mode/control_bits"
  • added check for dimension of "instructions//cc/[signals,ref_signal]/value" against "instruments/ref_control_mode/control_bits"
  • added cross check of "instruments/ref_control_mode" against "instrument_definitions"
  • added support for "pragma/break" in JSON definition to define 'gate' that breaks out of loop
  • added support to distribute measurement results via DSM
  • added support for conditional gates
  • added compile option "--backend_cc_run_once"
  • added compile option "--backend_cc_verbose"

Changed

• pass management: instead of a hardcoded compilation strategy, the strategy can be adjusted and fine-tuned manually
• pass options: instead of doing everything with global options, global options were replaced with pass options as much as possible
• most documentation is now generated from code and can be queried using API calls
• scheduler resources are completely reworked to be made more generic
• major internal refactoring and restructuring to facilitate the above two things
• CC backend:
  • renamed JSON field "signal_ref" to "ref_signal"
  • renamed JSON field "ref_signals_type" to "signal_type"
  • changed JSON field "static_codeword_override" to be a vector with one element per qubit parameter. To edit a JSON file using Sublime, use Replace with Regular Expressions: find="static_codeword_override": ([0-9])+, replace="static_codeword_override": [\1]
  • adopted new module synchronization scheme ("seq_bar semantics", requires CC software >= v0.2.0, PycQED after commit 470df5b)
  • JSON field "instruction/type" no longer used by backend, use "instruction/cc/readout_mode" to flag measurement instructions
  • allow specification of 2 triggers in JSON field "control_modes/*/trigger_bits" to support dual-QWG
  • changed label in generated code from "mainLoop" to "mainLoop". Do not start kernel names with "" (this should be specified by the API)
  • removed initial 1 cycle (20 ns) delay at start of kernels (resulting from bundle start_cycle starting at 1)
  • correctly handle kernel names containing "_" in conjunction with looping (formerly duplicate labels could arise)
  • added "seq_out 0,1" to program start to allow tracing of actual program start

Removed

• CC-light code generation, as the CC-light is being phased out in the lab, and its many passes were obstacles for pass management and refactoring
• rotation optimization based on matrices; matrices in general were removed entirely because no one was using it
• the commute variation pass, as it has been superseded by in-place commutations within the scheduler
• the toffoli decomposition pass, as it wasn't really used; to decompose a toffoli gate, use generic platform-driven decomposition instead
• the defunct fidelity estimation logic from metrics.cc; this may be added again later, but requires lots of cleanup and isn't currently in use
• quantumsim and qsoverlay output; apparently this was no longer being used, and it was quite intertwined with the CC-light backend

Fixed

• changed register used for FOR loop, so it doesn't clash with delay setting
• fixed documentation for python setup and running tests
• various miscellaneous bugs, dangling pointers, and memory leaks