java,signal-processing,fft,audio-fingerprinting,windowing

At first, I think you should consider having your FFT length fixed. If I understand your code correctly, you are now using some kind of minimum buffer size also as the FFT length. FFT length has huge effect on the performance and resolution of your calculation. Your link to WindowFunction.java...

signal-processing,dft,windowing,kissfft

Frequency domain output clarifications In the frequency domain, the rectangular and Hamming windows look like: As you may be aware, multiplication in the time domain by a window corresponds to a convolution in the frequency domain, which essentially spreads the energy of the signal over multiple frequency bins in what...

sql,sql-server,tsql,row-number,windowing

You can use two CTE's, one for past and one for future dates, then use ROW_NUMBER with ASC and DESC, multiply before now with -1 and concat all: WITH dataBefore AS ( SELECT d.*, rn = (-1) * row_Number() over (Order By CalculatedOn DESC) FROM dbo.TableName d WHERE CalculatedOn <...

sql,distinct,netezza,windowing

You can always resort to brute force -- that is, to a correlated subquery: select redemption_date, count(distinct(customer_id)) as day_redeemers, (select count(distinct ch2.customer_id) from coupon_history ch2 where ch2.redemption_date <= ch.redemption_date ) as cml_redeemers from coupon_history ch group by 1 order by 1; Of course, performance will not be as good. EDIT:...