diff --git a/cmd/main.cpp b/cmd/main.cpp
index 0d761e2..2b01b79 100644
--- a/cmd/main.cpp
+++ b/cmd/main.cpp
@@ -2,15 +2,17 @@
 #include <iostream>
 #define LOG_EXPR(expr) std::cout << #expr << " = " << (expr) << "\n";
 
+#ifdef PROFILE_PLOT_CHUNKS
 size_t activeStepIndex = 0;
 void profileProcessStart(int, int);
 void profileProcessEndStep();
 void profileProcessStep(size_t, size_t);
 void profileProcessEnd();
-#define SIGNALSMITH_STRETCH_PROFILE_PROCESS_START profileProcessStart
-#define SIGNALSMITH_STRETCH_PROFILE_PROCESS_STEP profileProcessStep
-#define SIGNALSMITH_STRETCH_PROFILE_PROCESS_ENDSTEP profileProcessEndStep
-#define SIGNALSMITH_STRETCH_PROFILE_PROCESS_END profileProcessEnd
+#	define SIGNALSMITH_STRETCH_PROFILE_PROCESS_START profileProcessStart
+#	define SIGNALSMITH_STRETCH_PROFILE_PROCESS_STEP profileProcessStep
+#	define SIGNALSMITH_STRETCH_PROFILE_PROCESS_ENDSTEP profileProcessEndStep
+#	define SIGNALSMITH_STRETCH_PROFILE_PROCESS_END profileProcessEnd
+#endif
 
 #include "signalsmith-stretch/signalsmith-stretch.h"
 
@@ -19,6 +21,7 @@ void profileProcessEnd();
 #include "./util/simple-args.h"
 #include "./util/wav.h"
 
+#ifdef PROFILE_PLOT_CHUNKS
 #include "plot/plot.h"
 std::vector<signalsmith::Stopwatch> processStopwatches;
 signalsmith::Stopwatch processStopwatchStart, processStopwatchEnd;
@@ -51,11 +54,14 @@ void profileProcessStep(size_t step, size_t count) {
 void profileProcessEnd() {
 	processStopwatchEnd.lap();
 }
+#endif
 
 int main(int argc, char* argv[]) {
 	signalsmith::stretch::SignalsmithStretch<float/*, std::ranlux48_base*/> stretch; // optional cheaper RNG for performance comparison
-	
+
+#ifdef PROFILE_PLOT_CHUNKS
 	processStopwatches.reserve(1000);
+#endif
 
 	SimpleArgs args(argc, argv);
 	
@@ -154,6 +160,7 @@ int main(int argc, char* argv[]) {
 		// the `.flush()` call already handled foldback stuff at the end (since we asked for a shorter `tailSamples`)
 	}
 
+#ifdef PROFILE_PLOT_CHUNKS
 	signalsmith::plot::Figure figure;
 	auto &plot = figure(0, 0).plot(400, 150);
 	plot.x.blank().label("step");
@@ -196,6 +203,7 @@ int main(int argc, char* argv[]) {
 	flatLine.add(0, 0);
 	flatLine.add(processStopwatches.size(), cumulativeTime);
 	figure.write("profile.svg");
+#endif
 
 	if (!outWav.write(outputWav).warn()) args.errorExit("failed to write WAV");
 	
diff --git a/signalsmith-stretch.h b/signalsmith-stretch.h
index a7c3b83..7814c95 100644
--- a/signalsmith-stretch.h
+++ b/signalsmith-stretch.h
@@ -11,11 +11,12 @@
 #include <algorithm>
 #include <functional>
 #include <random>
+#include <type_traits>
 
 namespace signalsmith { namespace stretch {
 
 namespace _impl {
-	template <bool conjugateSecond=false, typename V>
+	template<bool conjugateSecond=false, typename V>
 	static std::complex<V> mul(const std::complex<V> &a, const std::complex<V> &b) {
 		return conjugateSecond ? std::complex<V>{
 			b.real()*a.real() + b.imag()*a.imag(),
@@ -25,9 +26,14 @@ namespace _impl {
 			a.real()*b.imag() + a.imag()*b.real()
 		};
 	}
+	template<typename V>
+	static V norm(const std::complex<V> &a) {
+		V r = a.real(), i = a.imag();
+		return r*r + i*i;
+	}
 }
 
-template<typename Sample=float, class RandomEngine=std::default_random_engine>
+template<typename Sample=float, class RandomEngine=void>
 struct SignalsmithStretch {
 	static constexpr size_t version[3] = {1, 1, 1};
 
@@ -475,10 +481,10 @@ private:
 		Complex input;
 
 		Complex makeOutput(Complex phase) {
-			Sample phaseNorm = std::norm(phase);
+			Sample phaseNorm = _impl::norm(phase);
 			if (phaseNorm <= noiseFloor) {
 				phase = input; // prediction is too weak, fall back to the input
-				phaseNorm = std::norm(input) + noiseFloor;
+				phaseNorm = _impl::norm(input) + noiseFloor;
 			}
 			return phase*std::sqrt(energy/phaseNorm);
 		}
@@ -488,7 +494,13 @@ private:
 		return channelPredictions.data() + c*bands;
 	}
 
-	RandomEngine randomEngine;
+	// If RandomEngine=void, use std::default_random_engine;
+	using RandomEngineImpl = std::conditional<
+		std::is_void<RandomEngine>::value,
+		std::default_random_engine,
+		RandomEngine
+	>::type;
+	RandomEngineImpl randomEngine;
 
 	size_t processSpectrumSteps = 0;
 	static constexpr size_t splitMainPrediction = 8; // it's just heavy, since we're blending up to 4 different phase predictions
@@ -550,7 +562,7 @@ private:
 				for (int c = 0; c < channels; ++c) {
 					Band *bins = bandsForChannel(c);
 					for (int b = 0; b < bands; ++b) {
-						bins[b].inputEnergy = std::norm(bins[b].input);
+						bins[b].inputEnergy = _impl::norm(bins[b].input);
 					}
 				}
 				for (int b = 0; b < bands; ++b) {
@@ -687,7 +699,7 @@ private:
 			for (int c = 0; c < channels; ++c) {
 				Band *bins = bandsForChannel(c);
 				for (int b = 0; b < bands; ++b) {
-					Sample e = std::norm(bins[b].input);
+					Sample e = _impl::norm(bins[b].input);
 					bins[b].inputEnergy = e; // Used for interpolating prediction energy
 					energy[b] += e;
 				}