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   -> Volume 4, Issue 11


Answer: Use of Numerical Recipes software (WD 4.9 #10)
 
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fournier@cloudy.geology.yale.edu
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PostPosted: Fri Dec 06, 2002 9:36 am    
Subject: Answer: Use of Numerical Recipes software (WD 4.9 #10)
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Answer: Use of Numerical Recipes software (WD 4.9 #10)

SUBROUTINE wt1tfa(a,n,aa,nmax,log_2n,wtstep) !Time/frequency analysis
!using Numerical Recipes wt1 by Press et al. (Cambridge, 2nd edition).
!This code by Aime' Fournier (fournier@cloudy.geology.yale.edu).
EXTERNAL wtstep !Requires n=2**log_2n.
REAL a(n) !Input signal becomes wavelet coefficient vector.
REAL aa(nmax,log_2n-1) !Output aa(.,j)=projection onto level j space.
CALL wt1(a,n,1,wtstep) !CALL pwtset before wt1tfa.
DO j=1,log_2n-1 !loop over timescales 2^j.
ncfcts=n/2**j !# coefficients at level j.
DO k=1,n !loop over time instants k.
IF ((ncfcts.LT.k).AND.(k.LE.2*ncfcts))THEN
aa(k,j)=a(k) !Keep only level j coefficients.
ELSE !mask coefficients corresponding other j levels:
aa(k,j)=0.
END IF
END DO
CALL wt1(aa(1,j),n,-1,wtstep) !Projection onto level j space.
END DO !The value aa(k,j) now corresponds to amplitude at time k
RETURN !and timescale 2^j.
END
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