IC89789: NOISY DATA IN SPECTRUM OUTPUT FROM FFT OPERATOR FOR LARGE DATA SETS

InfoSphere Streams Version 3.0 Fix Pack 1

APAR status

• Closed as program error.

Error description

• When you have an SPL application that uses an FFT operator and
  the algorithm parameter is set to complexFFT, realFFT,
  inverseRealFFT, or inverseComplexFFT,  noisy data or unwanted
  artifacts are visible in the output spectrum.   This problem is
  more likely to occur when the input data set is large.
  The problem does not occur when the algorithm parameter is set
  to realDFT.
  

Local fix

• You can work around the problem by setting the algorithm
  parameter to realDFT, but this algorithm has less accurate
  results, particularly when compared to complexFFT and
  inverseComplexFFT.
  

Problem summary

• See Error Description.
  

Problem conclusion

• This problem is fixed in Version 3.0 Fix Pack 1 and later fix
  packs.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Modules/Macros

• FFT
  

Fix information

• Fixed component name

  INFOSPHERE STRE

• Fixed component ID

  5724Y95IS

Applicable component levels

• R300 PSY

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