search for: periodicti

R-listers, I am using xts with a yearmon index, but am getting some inconsistent results with the date index when i drop observations (for example by using na.omit). The issue is illustrated in the example below. If I start with a monthly zooreg series starting in 2009, yearmon converts this to "Dec-2008". Not such a worry for my example, but strange. Having converted to xts, i drop

Hi everyone, I am trying to fit a sine function on one year of wind data. I have two questions below. Looking around on the net I managed to get the following: Sine Equation: y = a + b * sin( c + d*x ) b is the amplitude, c is the phase shift, d is something deal with periodicty of data*.* This can be linearised by sin( c+dx ) = cos(c) * sin(dx) + sin(c) * cos(dx). If one calls dx = x1 y