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On "cleaning" residual values from complex matrices
From: |
Roberto Hernandez |
Subject: |
On "cleaning" residual values from complex matrices |
Date: |
Fri, 18 Jan 2002 15:31:43 -0300 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.6) Gecko/20011120 |
Hello everyone,
I've been doing a lot of processing with FFT. While the magnitude of the
results I've been getting makes perfect sense, I noticed the phase was
totally incongruent. After looking into the problem, I realized it boils
down to residual values. What's happening is that values that should be
zero show up as something like +/-eps +/-eps*i, so that throws off any
phase calculations.
Is there any function that "cleans" residual values (makes them zero)? I
looked up "precision" in the help files and found information on the
built in variables 'realmin', 'realmax' and 'eps'. However, I found no
"cleaning" functions.
If it's not available, I don't have a problem with writing my own. I'm
not an expert in numerical analysis, so I figure it's very likely that
I'll overlook something. My idea is to check for values where the
real/imaginary part is <= 'eps' and truncating the real/imaginary part
for those values to zero.
If there is already a function that does this, please let me know.
Otherwise, if I do have to write my own, is there anything else the
function should do besides what I already mentioned?
TIA,
Roberto
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- On "cleaning" residual values from complex matrices,
Roberto Hernandez <=