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Aug
26
comment Extrapolation and Splines
Hi null. Thanks for getting back to me. I guess I am letting my frustration get the better of me. I am a stats guy (and an economist also; you got me). I have hired a small army of consultants and still it is not solved.. SWMA: the impulse response looks like the first half of a sinusoid. Your best friend google knows better. So imagine there was something you needed in a field you knew nothing about. Like.. Nouvelle cuisine or whatever. What are the indicators of future success? Of getting the problem solved?
Aug
25
comment Extrapolation and Splines
What makes you think this is related to financial markets? The process is a sine-weighted moving average. And no, this is not better suited for the stats guys. Sure is difficult to find the right expert for specific questions. Any pointers on that please? Thanks.
Aug
22
asked Extrapolation and Splines
May
22
awarded  Enthusiast
May
6
comment Chirp with linearly changing frequency and amplitude?
Could you use this "linear amplitude & frequency chirp" function to do a regression to estimate the instantaneous frequency of a smooth curve in real time (online analysis)?
May
6
accepted Chirp with linearly changing frequency and amplitude?
May
6
comment Chirp with linearly changing frequency and amplitude?
I don't think so. Ideally I would also define an A0 and A1: the starting and ending amplitude, so the amplitude "line" goes from (1,A0) to (T,A1), so the equation of this line would be: y-A0=(A1-A0)/(T-1)(x-1). Thinking of the standard equation of a sinusoid, which is Asin*(2pif*t+theta0), in that case you first multiply with the amplitude. So instead of a constant, it would be the equation of the amplitude line?
May
6
asked Chirp with linearly changing frequency and amplitude?
May
4
accepted Convert quadratic bezier curve to parabola
Apr
30
revised Convert quadratic bezier curve to parabola
added 274 characters in body
Apr
30
revised Convert quadratic bezier curve to parabola
added 210 characters in body
Apr
29
revised Convert quadratic bezier curve to parabola
added 6 characters in body
Apr
29
answered Convert quadratic bezier curve to parabola
Apr
29
revised Convert quadratic bezier curve to parabola
added 31 characters in body
Apr
29
revised Convert quadratic bezier curve to parabola
added 89 characters in body
Apr
29
revised Convert quadratic bezier curve to parabola
added a link
Apr
29
comment Convert quadratic bezier curve to parabola
The control points are known, so logically the red Bézier curve is known also. The coordinate system is a Cartesian grid, with constant increments of 1 on both Y & X axes. The solution has to be related to the fact that the line through P0 & P1 is tangent to the Bézier curve in P0 and P1P2 tangent to the curve in P2. So the slope of the tangent to the parabola = the slope of these 2 lines. And the point where these 2 lines cross is P1. And to get c I think you need to plug in the x values of P0 and P1 into the ax^2+bx+c equation to get their y-value after you know a & b. I think..
Apr
29
asked Convert quadratic bezier curve to parabola
Apr
7
accepted Bezier extrapolation
Apr
3
comment Bezier extrapolation
So I guess I am looking for the ab-normal way to do this. It really should not require an iterative process. Could you suggest another spline with similar properties that would not have this problem?