nmrglue.process.proc_lp.find_lproots_hsvd

nmrglue.process.proc_lp.find_lproots_hsvd(x, M, K, mode, zmethod='sm')

Find LP roots (poles) using the HSVD method

Parameters:

• x 1D trace of data, the FID.

• M Length (M+1) of data matrix to form

• K Reduced prediction order (number of signal roots)

  K < min(M+1,len(x)-M)

• mode Mode to perform LP (f-forward,b-backward)

• zmethod Method used to find Z’ (lstsq-least squares, sm-Sherman-Morrison)

Returns array of signal roots (poles)

Perform a HSVD linear prediction to determind signal roots (poles) as described in: Barkhuijsen, DeBeer, and VanOrmondt, JMR, 1987, 73, 553

Parameters x, M and K are the same as those described in the above article. zmethod refer to the method used to calculate Z’, either a least-squares method (lstsq) can be used to solve U_b*Z’=U_t or the Sherman-Morrison formula (sm) can be used to avoid the full matrix inversion with equation [12] being used to find Z’. The Sherman-Morrison method should be faster with similar precision.