ntopng/attic/TimeSeries.cpp
2023-01-16 11:47:39 +01:00

71 lines
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2.4 KiB
C++

/*
*
* (C) 2013-16 - ntop.org
*
*
* 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
* (at your option) 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, write to the Free Software Foundation,
* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
#include "ntop_includes.h"
template <class T> TimeSeries<T>::TimeSeries(u_int32_t _max_datapoints){
max_datapoints = _max_datapoints;
num_datapoints = next_datapoint_index = 0;
xs.reserve(max_datapoints);
ys.reserve(max_datapoints);
}
template<class T> u_int8_t TimeSeries<T>::addDataPoint(T x, T y){
if(x != 0 and y != 0)
ntop->getTrace()->traceEvent(TRACE_DEBUG,
"Adding datapoint: x=%.2f y=%.2f", x, y);
if ((num_datapoints + 1) > max_datapoints) return -1;
xs[next_datapoint_index] = x;
ys[next_datapoint_index] = y;
num_datapoints++;
next_datapoint_index++;
return 0;
}
template<class T> double TimeSeries<T>::discreteDerivative(bool normalized){
if(num_datapoints <= 1)
numeric_limits<double>::quiet_NaN(); // cannot derive
double d_sum = 0;
for (u_int32_t i = 1; i < num_datapoints; i++){
double d = 0;
if(xs[i] == xs[i-1]) continue; // prevent zero-division errors
d = (ys[i] - ys[i-1]) / (xs[i] - xs[i-1]);
d_sum += d;
if (d != 0){
ntop->getTrace()->traceEvent(TRACE_DEBUG,
"Deriving: xs[i]=%.2f xs[i-1]=%.2f", xs[i], xs[i-1]);
ntop->getTrace()->traceEvent(TRACE_DEBUG,
"Deriving: ys[i]=%.2f ys[i-1]=%.2f", ys[i], ys[i-1]);
ntop->getTrace()->traceEvent(TRACE_DEBUG, "Deriving: result %.2f", d);
}
}
// average the derivative
d_sum /= (double)num_datapoints;
if (!normalized)
return d_sum;
else{
// obtain the angle theta that the average slopes have with the x-axis
return atan(d_sum);
}
}
template class TimeSeries<float>;