Rank: 4663 based on 26 downloads (last 30 days) and 3 files submitted
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Robert Dickson

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Company/University
L-3 Communications
Lat/Long
40.67, -111.89

Personal Profile:

My long career in communications technology started in San Diego at the Navy Electronics Lab and Linkabit. Current interests include software channel simulation, mutual information-based link performance measures, effective SNR of interleaved fading channels, OFDM synchronization analysis, and theory of random processes.


 

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Files Posted by Robert Dickson View all
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09 Jun 2014 qrseq.m Quadratic residue Legendre sequences Author: Robert Dickson legendre symbol, binary sequence, correlation, quadratic residue 3 0
12 Jun 2013 Screenshot Bessel Polynomial Linearization Coefficients Linearization coefficients for Bessel polynomials, and certain rational polynomial spectra. Author: Robert Dickson mathematics, bessel polynomial, linearization coeffic..., rational polynomial s..., communications, fading channel 13 0
  • 3.0
3.0 | 1 rating
30 Mar 2006 maxstar Natural log of a sum of exponentials Author: Robert Dickson coding theory, information theory, precision, metric, coding, natural log 10 1
  • 4.0
4.0 | 1 rating
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07 Dec 2013 Bessel Polynomial Linearization Coefficients Linearization coefficients for Bessel polynomials, and certain rational polynomial spectra. Author: Robert Dickson Parvesh

08 Mar 2006 maxstar Natural log of a sum of exponentials Author: Robert Dickson

Good help with a reference. It works when the direct alternative expression fails. But there are other (faster) alternatives that should be as accurate. Off hand, its not at all obvious to me why maxstar is better. (Perhaps if I've read the reference.)

x = randn(1,100)*100000;

tic,r1=log(sum(exp(x(:))));toc
Elapsed time is 0.000178 seconds.

tic,r2=maxstar(x);toc
Elapsed time is 0.017096 seconds.

tic,M=max(x(:));r3=M+log(sum(exp(sort(x(:))/M)));toc
Elapsed time is 0.000342 seconds.

[r1,r2,r3]
ans =
Inf 2.7718e+05 2.7718e+05

Its also arguable that this should have a similar syntax to most other matlab operators with similar functionality. It should operate on a specified dimension. (See help for mean, max, etc.)

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