Post select (#177)

Added support for post-selection

.clang-tidy

@@ -0,0 +1,207 @@
+FormatStyle: file
+# WarningsAsErrors: "*"
+Checks: "-*,
+  abseil-*,\
+  -abseil-string-find-startswith,\
+  -abseil-string-find-str-contains,\
+  bugprone-*,\
+  -bugprone-argument-comment,\
+  -bugprone-assert-side-effect,\
+  -bugprone-bad-signal-to-kill-thread,\
+  -bugprone-bool-pointer-implicit-conversion,\
+  -bugprone-branch-clone,\
+  -bugprone-copy-constructor-init,\
+  -bugprone-dangling-handle,\
+  -bugprone-dynamic-static-initializers,\
+  -bugprone-easily-swappable-parameters,\
+  -bugprone-exception-escape,\
+  -bugprone-fold-init-type,\
+  -bugprone-forward-declaration-namespace,\
+  -bugprone-forwarding-reference-overload,\
+  -bugprone-implicit-widening-of-multiplication-result,\
+  -bugprone-inaccurate-erase,\
+  -bugprone-incorrect-roundings,\
+  -bugprone-infinite-loop,\
+  -bugprone-integer-division,\
+  -bugprone-lambda-function-name,\
+  -bugprone-macro-parentheses,\
+  -bugprone-macro-repeated-side-effects,\
+  -bugprone-misplaced-operator-in-strlen-in-alloc,\
+  -bugprone-misplaced-widening-cast,\
+  -bugprone-move-forwarding-reference,\
+  -bugprone-multiple-statement-macro,\
+  -bugprone-narrowing-conversions,\
+  -bugprone-no-escape,\
+  -bugprone-not-null-terminated-result,\
+  -bugprone-parent-virtual-call,\
+  -bugprone-posix-return,\
+  -bugprone-redundant-branch-condition,\
+  -bugprone-reserved-identifier,\
+  -bugprone-signal-handler,\
+  -bugprone-signed-char-misuse,\
+  -bugprone-sizeof-container,\
+  -bugprone-sizeof-expression,\
+  -bugprone-spuriously-wake-up-functions,\
+  -bugprone-string-constructor,\
+  -bugprone-string-integer-assignment,\
+  -bugprone-string-literal-with-embedded-nul,\
+  -bugprone-stringview-nullptr,\
+  -bugprone-suspicious-enum-usage,\
+  -bugprone-suspicious-include,\
+  -bugprone-suspicious-memory-comparison,\
+  -bugprone-suspicious-memset-usage,\
+  -bugprone-suspicious-missing-comma,\
+  -bugprone-suspicious-semicolon,\
+  -bugprone-suspicious-string-compare,\
+  -bugprone-swapped-arguments,\
+  -bugprone-terminating-continue,\
+  -bugprone-throw-keyword-missing,\
+  -bugprone-too-small-loop-variable,\
+  -bugprone-undefined-memory-manipulation,\
+  -bugprone-undelegated-constructor,\
+  -bugprone-unhandled-exception-at-new,\
+  -bugprone-unhandled-self-assignment,\
+  -bugprone-unused-raii,\
+  -bugprone-unused-return-value,\
+  -bugprone-use-after-move,\
+  -bugprone-virtual-near-miss,\
+  cert-*,\
+  -cert-dcl16-c,\
+  -cert-dcl21-cpp,\
+  -cert-dcl37-c,\
+  -cert-dcl50-cpp,\
+  -cert-dcl51-cpp,\
+  -cert-dcl54-cpp,\
+  -cert-dcl58-cpp,\
+  -cert-err33-c,\
+  -cert-msc30-c,\
+  -cert-msc32-c,\
+  -cert-msc50-cpp,\
+  -cert-msc51-cpp,\
+  -cert-oop54-cpp,\
+  -cert-str34-c,\
+  -cert-str34-c,\
+  -cert-str34-c,\
+  -cert-str34-c,\
+  -clang-analyzer-*,\
+  concurrency-*,\
+  -concurrency-mt-unsafe,\
+  cppcoreguidelines-*,\
+  -concurrency-mt-unsafe,\
+  -cppcoreguidelines-avoid-c-arrays,\
+  -cppcoreguidelines-avoid-const-or-ref-data-members,\
+  -cppcoreguidelines-avoid-do-while,\
+  -cppcoreguidelines-avoid-goto,\
+  -cppcoreguidelines-avoid-magic-numbers,\
+  -cppcoreguidelines-avoid-non-const-global-variables,\
+  -cppcoreguidelines-c-copy-assignment-signature,\
+  -cppcoreguidelines-explicit-virtual-functions,\
+  -cppcoreguidelines-init-variables,\
+  -cppcoreguidelines-interfaces-global-init,\
+  -cppcoreguidelines-macro-usage,\
+  -cppcoreguidelines-narrowing-conversions,\
+  -cppcoreguidelines-no-malloc,\
+  -cppcoreguidelines-non-private-member-variables-in-classes,\
+  -cppcoreguidelines-owning-memory,\
+  -cppcoreguidelines-prefer-member-initializer,\
+  -cppcoreguidelines-pro-bounds-array-to-pointer-decay,\
+  -cppcoreguidelines-pro-bounds-constant-array-index,\
+  -cppcoreguidelines-pro-bounds-pointer-arithmetic,\
+  -cppcoreguidelines-pro-type-const-cast,\
+  -cppcoreguidelines-pro-type-member-init,\
+  -cppcoreguidelines-pro-type-reinterpret-cast,\
+  -cppcoreguidelines-pro-type-static-cast-downcast,\
+  -cppcoreguidelines-pro-type-union-access,\
+  -cppcoreguidelines-pro-type-vararg,\
+  -cppcoreguidelines-slicing,\
+  -cppcoreguidelines-special-member-functions,\
+  -cppcoreguidelines-virtual-class-destructor,\
+  google-*,\
+  -google-default-arguments,\
+  -google-explicit-constructor,\
+  -google-readability-avoid-underscore-in-googletest-name,\
+  -google-readability-braces-around-statements,\
+  -google-readability-casting,\
+  -google-readability-namespace-comments,\
+  -google-readability-todo,\
+  -google-runtime-int,\
+  -google-upgrade-googletest-case,\
+  misc-*,\
+  -misc-misplaced-const,\
+  -misc-new-delete-overloads,\
+  -misc-non-private-member-variables-in-classes,\
+  -misc-no-recursion,\
+  -misc-redundant-expression,\
+  -misc-uniqueptr-reset-release,\
+  -misc-unconventional-assign-operator,\
+  -misc-unused-parameters,\
+  -misc-unused-using-decls,\
+  modernize-*,\
+  -modernize-avoid-c-arrays,\
+  -modernize-concat-nested-namespaces,\
+  -modernize-deprecated-headers,\
+  -modernize-loop-convert,\
+  -modernize-macro-to-enum,\
+  -modernize-make-unique,\
+  -modernize-pass-by-value,\
+  -modernize-raw-string-literal,\
+  -modernize-redundant-void-arg,\
+  -modernize-return-braced-init-list,\
+  -modernize-unary-static-assert,\
+  -modernize-use-auto,\
+  -modernize-use-bool-literals,\
+  -modernize-use-default-member-init,\
+  -modernize-use-emplace,\
+  -modernize-use-equals-default,\
+  -modernize-use-equals-delete,\
+  -modernize-use-nodiscard,\
+  -modernize-use-override,\
+  -modernize-use-trailing-return-type,\
+  -modernize-use-transparent-functors,\
+  -modernize-use-using,\
+  performance-*,\
+  -performance-faster-string-find,\
+  -performance-for-range-copy,\
+  -performance-inefficient-algorithm,\
+  -performance-inefficient-string-concatenation,\
+  -performance-inefficient-vector-operation,\
+  -performance-move-const-arg,\
+  -performance-no-automatic-move,\
+  -performance-noexcept-move-constructor,\
+  -performance-no-int-to-ptr,\
+  -performance-trivially-destructible,\
+  -performance-unnecessary-copy-initialization,\
+  -performance-unnecessary-value-param,\
+  portability-*,\
+  readability-*,\
+  -readability-avoid-const-params-in-decls,\
+  -readability-braces-around-statements,\
+  -readability-const-return-type,\
+  -readability-container-data-pointer,\
+  -readability-container-size-empty,\
+  -readability-convert-member-functions-to-static,\
+  -readability-else-after-return,\
+  -readability-function-cognitive-complexity,\
+  -readability-identifier-length,\
+  -readability-implicit-bool-conversion,\
+  -readability-inconsistent-declaration-parameter-name,\
+  -readability-isolate-declaration,\
+  -readability-magic-numbers,\
+  -readability-make-member-function-const,\
+  -readability-named-parameter,\
+  -readability-non-const-parameter,\
+  -readability-qualified-auto,\
+  -readability-redundant-access-specifiers,\
+  -readability-redundant-control-flow,\
+  -readability-redundant-declaration,\
+  -readability-redundant-member-init,\
+  -readability-redundant-smartptr-get,\
+  -readability-redundant-string-cstr,\
+  -readability-redundant-string-init,\
+  -readability-simplify-boolean-expr,\
+  -readability-static-accessed-through-instance,\
+  -readability-static-definition-in-anonymous-namespace,\
+  -readability-suspicious-call-argument,\
+  -readability-uppercase-literal-suffix,\
+  -readability-use-anyofallof
+  "

.github/workflows/cmake.yml

@@ -13,7 +13,8 @@ jobs:
   build:
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
+        # os: [ubuntu-latest, macos-latest, windows-latest]
+        os: [ubuntu-latest, macos-latest]
     runs-on: ${{ matrix.os }}
 
     steps:
@@ -67,10 +68,10 @@ jobs:
       - name: Install pyqpp
         shell: bash
         run: |
-          python3 -m venv venv
+          python3 -mvenv venv
           if [ "$RUNNER_OS" == "Windows" ]; then
-            venv/Scripts/activate
+            venv\Scripts\Activate
           else
-            . venv/bin/activate
+            source venv/bin/activate
           fi
           pip3 install .

.gitignore

@@ -66,6 +66,7 @@ mat.txt
 examples/_*.cpp
 out.tmp
 TODO.txt
+test
 
 # pyqpp
 Makefile

CHANGES.md

@@ -1,5 +1,51 @@
 # Pre-release
 
+- Breaking change: renamed ["qpp/qpp.h"] to ["qpp/qpp.hpp"]
+- New feature: implemented support for post-selection in
+  ["qpp/classes/qengine.hpp"] and ["qpp/classes/qcircuit.hpp"]
+- Implemented `qpp::QCircuit::`
+  - `QCircuit& post_select()` - destructive/non-destructive post-selection of
+    single/multiple qudits in the Z basis
+  - `QCircuit& post_selectV()` - destructive/non-destructive post-selection of
+    single/multiple qudits in an arbitrary orthonormal basis
+- Implemented `qpp::QEngineT<>::`
+  - `bool get_ensure_post_selection() const` - True if post-selection is
+    enforced, false otherwise
+  - `QEngineT<>& set_ensure_post_selection()` - Enforces post-selection (i.e.,
+    post-selection steps are repeated until success)
+  - `idx get_max_post_selection_reps() const` - Maximum number of executions of
+    a circuit post-selection step until success
+  - `QEngineT<>& set_max_post_selection_reps()` - Sets the maximum number of
+    executions of a circuit post-selection step until success
+  - `bool post_select_ok() const` - True if post-selection was successful (or
+    absent), false otherwise
+- Added
+  [["examples/circuits/post_selection.cpp"](https://github.com/softwareQinc/qpp/blob/main/examples/circuits/post_selection.cpp)]
+  example
+- Refactored `qpp::QCircuit::GateStep/MeasurementStep/NOPStep` into separate
+  files ["qpp/internal/classes/qcircuit_gate_step.hpp"],
+  ["qpp/internal/classes/qcircuit_measurement_step.hpp"], and
+  ["qpp/internal/classes/qcircuit_nop_step.hpp"], respectively
+- Refactored `qpp::QCircuit::Resources` into an independent class in a separate
+  file ["qpp/internal/classes/qcircuit_resources.hpp"]
+- Refactored qpp::QCircuit::iterator class into an independent class, defined
+  outside qpp::QCircuit in ["qpp/classes/qcircuit.hpp"]
+- Refactored `qpp::internal::QEngineState` and
+  `qpp::internal::QEngineStatistics`
+  in separate files, ["qpp/internal/classes/qengine_state.hpp"] and
+  ["qpp/internal/classes/qengine_statistics.hpp"], respectively
+- API changes in ["qpp/classes/qcircuit.hpp"]
+  - `qpp::QCircuit::get_measured()` -> `qpp::QCircuit::get_measured_d()`
+  - `qpp::QCircuit::get_non_measured()` -> `qpp::QCircuit::get_non_measured_d()`
+  - `qpp::QCircuit::was_measured()` -> `qpp::QCircuit::was_measured_d()`
+- API changes in ["qpp/classes/qengine.hpp"]
+  - `qpp::QEngineT<>::get_measured()` -> `qpp::QEngineT<>::get_measured_d()`
+  - `qpp::QEngineT<>::get_non_measured()` ->
+    `qpp::QEngineT<>::get_non_measured_d()`
+  - `qpp::QEngineT<>::was_measured()` -> `qpp::QEngineT<>::was_measured_d()`
+- Bugfix in qpp::internal::canonical_form(), the re-ordering is now stable, so
+  qpp::QCircuit measurement probabilities are not displayed in reversed order
+  w.r.t. target
 - Simplified MATLAB detection via CMake `find_package()` function. Users should
   only use `-DQPP_MATLAB=ON` when building with MATLAB support, all other
   MATLAB-related CMake flags have been removed.
@@ -25,17 +71,17 @@
   - ["qpp/classes/qnoisy_engine.hpp"] - noisy quantum engines
 - Introduced ["qpp/classes/qengine_traits.hpp"] that implement
   engine traits at run-time. All engines are now deriving from it.
-  The traits implements qpp::IQEngineTraits::
+  The traits implements `qpp::IQEngineTraits::`
   - `std::string traits_get_name() const` - Engine's name
   - `bool traits_is_noisy() const` - Simulates noisy execution
   - `bool traits_is_pure() const` - Operates on pure states
 - API changes in ["qpp/classes/qengine.hpp"] and
   ["qpp/classes/qnoisy_engine.hpp"]
   - Enabled mixed-state engines by refactoring
-    `qpp::QEngine` -> `template<typename T> qpp::QEngineT<T>`
-    `qpp::QNoisyEngine` -> `template<typename T> qpp::QNoisyEngineT<T>`
-    The template argument T is restricted to `qpp::ket` (pure state
-    engines) and `qpp::cmat` (mixed states engines)
+    - `qpp::QEngine` -> `template<typename T> qpp::QEngineT<T>`
+    - `qpp::QNoisyEngine` -> `template<typename T> qpp::QNoisyEngineT<T>`
+      The template argument T is restricted to `qpp::ket` (pure state
+      engines) and `qpp::cmat` (mixed states engines)
   - The following additional engines are now available
     - `qpp::QEngine` - pure state ideal engine, backwards
       compatibility
@@ -45,8 +91,8 @@
       compatibility
     - `qpp::QKetNoisyEngine` - same as `qpp::QNoisyEngine`
     - `qpp::QDensityNoisyEngine` - mixed state noisy engine
-  - Renamed `qpp::QEngineT::get_psi()` -> `qpp::QEngineT::get_state()`
-  - Removed `qpp::QEngineT::is_noisy()`
+  - Renamed `qpp::QEngineT<>::get_psi()` -> `qpp::QEngineT<>::get_state()`
+  - Removed `qpp::QEngineT<>::is_noisy()`
   - Added the new engines to **pyqpp**, which now defines the following
     factory functions for instantiating engines
     - `pyqpp.QEngine()` - pure state ideal engine, backwards
@@ -58,9 +104,9 @@
     - `pyqpp.QKetNoisyEngine()` - same as `pyqpp.QNoisyEngine()`
     - `pyqpp.QDensityNoisyEngine()` - mixed state noisy engine
   - Removed the default argument `bool try_sampling = true` in
-    `qpp::QEngineT::execute(idx reps = 1, bool try_sampling = true)` ->
-    `qpp::QEngineT::execute(idx reps = 1)`
-    so now `qpp::QEngineT` will always try to sample from the output when
+    `qpp::QEngineT<>::execute(idx reps = 1, bool try_sampling = true)` ->
+    `qpp::QEngineT<>::execute(idx reps = 1)`
+    so now `qpp::QEngineT<>` will always try to sample from the output when
     the circuit is executed multiple times (i.e., when `reps > 1`)
 - Introduced no-op (dummy) quantum engines in ["qpp/classes/qdummy_engine.hpp"]
   that provides