rms: add new RMS hook

lib/hooks/CMakeLists.txt

@@ -35,6 +35,7 @@ set(HOOK_SRC
     limit_rate.cpp
     limit_value.cpp
     restart.cpp
+    rms.cpp
     scale.cpp
     shift_seq.cpp
     shift_ts.cpp

lib/hooks/rms.cpp

@@ -0,0 +1,206 @@
+/** RMS hook.
+ *
+ * @author Manuel Pitz <manuel.pitz@eonerc.rwth-aachen.de>
+ * @copyright 2014-2020, Institute for Automation of Complex Power Systems, EONERC
+ * @license GNU General Public License (version 3)
+ *
+ * VILLASnode
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *********************************************************************************/
+
+/** @addtogroup hooks Hook functions
+ * @{
+ */
+
+#include <cstring>
+#include <cinttypes>
+#include <vector>
+#include <villas/timing.h>
+#include <villas/hook.hpp>
+#include <villas/path.h>
+#include <villas/sample.h>
+
+namespace villas {
+namespace node {
+
+class RMSHook : public Hook {
+
+protected:
+	std::vector<std::vector<double>> smpMemory;
+
+	uint64_t calcCount;
+	unsigned rate;
+	unsigned windowSize;
+	bool sync;
+	double nextCalc;
+
+	uint64_t smpMemPos;
+	uint64_t lastSequence;
+	struct timespec lastCalc;
+
+	std::vector<int> signalIndex;	/**< A list of signalIndex to do rms on */
+
+public:
+	RMSHook(struct vpath *p, struct vnode *n, int fl, int prio, bool en = true) :
+		Hook(p, n, fl, prio, en),
+		smpMemory(),
+		calcCount(0),
+		rate(0),
+		windowSize(0),
+		sync(0),
+		nextCalc(0.0),
+		smpMemPos(0),
+		lastSequence(0),
+		lastCalc({0, 0}),
+		signalIndex()
+	{ }
+
+	virtual void prepare()
+	{
+		signal_list_clear(&signals);
+		for (unsigned i = 0; i < signalIndex.size(); i++) {
+			struct signal *amplSig;
+
+			/* Add signals */
+			amplSig = signal_create("rms", "", SignalType::FLOAT);
+
+			if (!amplSig)
+				throw RuntimeError("Failed to create new signals");
+
+			vlist_push(&signals, amplSig);
+		}
+
+		/* Initialize sample memory */
+		smpMemory.clear();
+		for (unsigned i = 0; i < signalIndex.size(); i++)
+			smpMemory.emplace_back(std::vector<double>(windowSize, 0.0));
+
+		state = State::PREPARED;
+	}
+
+	virtual void parse(json_t *cfg)
+	{
+		int ret;
+		json_error_t err;
+
+		json_t *jsonChannelList = nullptr;
+
+		assert(state != State::STARTED);
+
+		Hook::parse(cfg);
+
+		ret = json_unpack_ex(cfg, &err, 0, "{ s?: i, s?: b, s?: i, s?: o }",
+			"window_size", &windowSize,
+			"sync", &sync,
+			"rate", &rate,
+			"signal_index", &jsonChannelList
+		);
+		if (ret)
+			throw ConfigError(cfg, err, "node-config-hook-rms");
+
+		if (jsonChannelList != nullptr) {
+			signalIndex.clear();
+			if (jsonChannelList->type == JSON_ARRAY) {
+				size_t i;
+				json_t *jsonValue;
+				json_array_foreach(jsonChannelList, i, jsonValue) {
+					if (!json_is_number(jsonValue))
+						throw ConfigError(jsonValue, "node-config-hook-rms-channel", "Values must be given as array of integer values!");
+
+					auto idx = json_number_value(jsonValue);
+
+					signalIndex.push_back(idx);
+				}
+			}
+			else if (jsonChannelList->type == JSON_INTEGER) {
+				if (!json_is_number(jsonChannelList))
+					throw ConfigError(jsonChannelList, "node-config-hook-rms-channel", "Value must be given as integer value!");
+
+				auto idx = json_number_value(jsonChannelList);
+
+				signalIndex.push_back(idx);
+			}
+			else
+				logger->warn("Could not parse channel list. Please check documentation for syntax");
+		}
+		else
+			throw ConfigError(jsonChannelList, "node-config-node-signal", "No parameter signalIndex given.");
+
+		state = State::PARSED;
+	}
+
+	virtual Hook::Reason process(struct sample *smp)
+	{
+		assert(state == State::STARTED);
+
+		for (unsigned i = 0; i < signalIndex.size(); i++)
+			smpMemory[i][smpMemPos % windowSize] = pow(smp->data[signalIndex[i]].f, 2);
+
+		smpMemPos++;
+
+		bool runRms = false;
+		if (sync) {
+			double smpNsec = smp->ts.origin.tv_sec * 1e9 + smp->ts.origin.tv_nsec;
+
+			if (smpNsec > nextCalc) {
+				runRms = true;
+				nextCalc = (( smp->ts.origin.tv_sec ) + ( ((calcCount % rate) + 1) / (double)rate )) * 1e9;
+			}
+		}
+
+		if (runRms) {
+			lastCalc = smp->ts.origin;
+
+			for (unsigned i = 0; i < signalIndex.size(); i++) {
+				double rms = 0;
+
+				for (unsigned j = 0; j < windowSize; j++)
+					rms += smpMemory[i][j];
+
+				rms = pow(rms / windowSize, 0.5) ;
+
+
+				if (calcCount > 1) {
+					smp->data[i * 4 + 0].f = rms; /* RMS */
+				}
+			}
+
+			smp->length = calcCount > 1 ? signalIndex.size() * 4 : 0;
+
+			calcCount++;
+		}
+
+		if (smp->sequence - lastSequence > 1)
+			logger->warn("Calculation is not Realtime. {} sampled missed", smp->sequence - lastSequence);
+
+		lastSequence = smp->sequence;
+
+		return runRms
+			? Reason::OK
+			: Reason::SKIP_SAMPLE;
+	}
+
+
+};
+
+/* Register hook */
+static char n[] = "rms";
+static char d[] = "This hook calculates the root-mean-square (RMS) on a window";
+static HookPlugin<RMSHook, n, d, (int) Hook::Flags::NODE_READ | (int) Hook::Flags::NODE_WRITE | (int) Hook::Flags::PATH> p;
+
+} /* namespace node */
+} /* namespace villas */
+
+/** @} */