Hopefully this variant is better

aromanro · Feb 22, 2025 · 37ea7b7 · 37ea7b7
1 parent 68b7bed
commit 37ea7b7
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Showing 2 changed files with 2 additions and 36 deletions.
diff --git a/QCSim/QubitRegister.h b/QCSim/QubitRegister.h
@@ -512,12 +512,7 @@ namespace QC {
 			const double prob = 1. - uniformZeroOne(rng); // this excludes 0 as probabiliy 
 
 			if (firstQubit == secondQubit)
-			{
-				if (!BaseClass::GetMultithreading() || NrBasisStates < BaseClass::OneQubitOmpLimit)
-					return BaseClass::MeasureQubitNoCollapse(NrBasisStates, registerStorage, firstQubit, prob);
-
-				return BaseClass::MeasureQubitNoCollapseOmp(NrBasisStates, registerStorage, firstQubit, prob);
-			}
+				return BaseClass::MeasureQubitNoCollapse(NrBasisStates, registerStorage, firstQubit, prob);
 
 			return BaseClass::MeasureNoCollapse(NrBasisStates, registerStorage, firstQubit, secondQubit, prob);
 		}

diff --git a/QCSim/QubitRegisterCalculator.h b/QCSim/QubitRegisterCalculator.h
@@ -342,17 +342,13 @@ namespace QC {
 			const size_t measuredQubitMask = 1ULL << qubit;
 
 			size_t state = 0;
-			std::atomic_bool found = false;
-
-#pragma omp parallel for reduction(+:accum) shared(found) num_threads(processor_count) schedule(static, OneQubitOmpLimit / divSchedule)
 			for (long long i = 0; i < NrBasisStates; ++i)
 			{
-				if (found) continue;
 				accum += std::norm(registerStorage(i));
 				if (prob <= accum)
 				{
 					state = i;
-					found = true;
+					break;
 				}
 			}
 
@@ -403,31 +399,6 @@ namespace QC {
 			return (state & measuredQubitMask) != 0 ? 1 : 0;
 		}
 
-		static inline size_t MeasureQubitNoCollapseOmp(size_t NrBasisStates, VectorClass& registerStorage, size_t qubit, const double prob)
-		{
-			double accum = 0;
-			const auto processor_count = GetNumberOfThreads();
-
-			const size_t measuredQubitMask = 1ULL << qubit;
-
-			size_t state = 0;
-			std::atomic_bool found = false;
-
-#pragma omp parallel for reduction(+:accum) shared(found) num_threads(processor_count) schedule(static, OneQubitOmpLimit / divSchedule)
-			for (long long i = 0; i < NrBasisStates; ++i)
-			{
-				if (found) continue;
-				accum += std::norm(registerStorage(i));
-				if (prob <= accum)
-				{
-					state = i;
-					found = true;
-				}
-			}
-
-			return (state & measuredQubitMask) != 0 ? 1 : 0;
-		}
-
 		static inline double GetQubitProbability(size_t NrBasisStates, const VectorClass& registerStorage, size_t qubit)
 		{
 			double accum = 0;