R help - Aug 2008 - Solving Yis[i] = a*cos((2*pi/T)*(times[i] - Tau)) + ...

Hi everybody,

I am reading the Lomb paper (Lomb, 1976) and I found an interesting
equation, and I wish to resolve it using R. I am wondering if anybody has a
hint. The equation is:

Yis[i] = a*cos((2*pi/T)*(Times[i] - Tau))  + b*sin((2*pi/T)*(Times[i] -
Tau)) ... (1)

Where T and Tau are constants.  I know the "Times" and "Tis"
values (in fact
these values come from a Time Series), and I need found the values of a and
b. I can resolve the eq. (1) using a pencil and paper (expanding this as a
linear system of equation), it is not a difficult problem, although I am not
able to resolve it using R.

Any hint or advice would be very appreciated,

Thank you so much

--
Josue  Polanco

	[[alternative HTML version deleted]]

Treat it as an over-determined linear system, that is:

    A <- cbind(cos((2*pi/T)*(Times - Tau)), sin((2*pi/T)*(Times - Tau)))
    qr.solve(A, Yis)

because 'solve' will only handle square matrices.

----
Hans W. Borchers


Josu? Polanco wrote:
> 
> Hi everybody,
> 
> I am reading the Lomb paper (Lomb, 1976) and I found an interesting
> equation, and I wish to resolve it using R. I am wondering if anybody has
> a
> hint. The equation is:
> 
> Yis[i] = a*cos((2*pi/T)*(Times[i] - Tau))  + b*sin((2*pi/T)*(Times[i] -
> Tau)) ... (1)
> 
> Where T and Tau are constants.  I know the "Times" and
"Tis" values (in
> fact
> these values come from a Time Series), and I need found the values of a
> and
> b. I can resolve the eq. (1) using a pencil and paper (expanding this as a
> linear system of equation), it is not a difficult problem, although I am
> not
> able to resolve it using R.
> 
> Any hint or advice would be very appreciated,
> 
> Thank you so much
> 
> --
> Josue  Polanco
> 
> 
-- 
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