J1. Fast Fourier transforms J4. Hilbert transforms J1. Fast Fourier transforms (search class L10 for time series analysis) FFTDOC-A Documentation for FFTPACK, a collection of Fast Fourier Transform routines. J1A. One-dimensional J1A1. Real EZFFTB-S A simplified real, periodic, backward fast Fourier transform. EZFFTF-S Compute a simplified real, periodic, fast Fourier forward transform. EZFFTI-S Initialize a work array for EZFFTF and EZFFTB. RFFTB1-S Compute the backward fast Fourier transform of a real CFFTB1-C coefficient array. RFFTF1-S Compute the forward transform of a real, periodic sequence. CFFTF1-C RFFTI1-S Initialize a real and an integer work array for RFFTF1 and CFFTI1-C RFFTB1. J1A2. Complex CFFTB1-C Compute the unnormalized inverse of CFFTF1. RFFTB1-S CFFTF1-C Compute the forward transform of a complex, periodic RFFTF1-S sequence. CFFTI1-C Initialize a real and an integer work array for CFFTF1 and RFFTI1-S CFFTB1. J1A3. Trigonometric (sine, cosine) COSQB-S Compute the unnormalized inverse cosine transform. COSQF-S Compute the forward cosine transform with odd wave numbers. COSQI-S Initialize a work array for COSQF and COSQB. COST-S Compute the cosine transform of a real, even sequence. COSTI-S Initialize a work array for COST. SINQB-S Compute the unnormalized inverse of SINQF. SINQF-S Compute the forward sine transform with odd wave numbers. SINQI-S Initialize a work array for SINQF and SINQB. SINT-S Compute the sine transform of a real, odd sequence. SINTI-S Initialize a work array for SINT. J4. Hilbert transforms QAWC-S The routine calculates an approximation result to a DQAWC-D Cauchy principal value I = INTEGRAL of F*W over (A,B) (W(X) = 1/((X-C), C.NE.A, C.NE.B), hopefully satisfying following claim for accuracy ABS(I-RESULT).LE.MAX(EPSABE,EPSREL*ABS(I)). QAWCE-S The routine calculates an approximation result to a DQAWCE-D CAUCHY PRINCIPAL VALUE I = Integral of F*W over (A,B) (W(X) = 1/(X-C), (C.NE.A, C.NE.B), hopefully satisfying following claim for accuracy ABS(I-RESULT).LE.MAX(EPSABS,EPSREL*ABS(I)) QC25C-S To compute I = Integral of F*W over (A,B) with DQC25C-D error estimate, where W(X) = 1/(X-C)