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BVLS (NNLS) without loops? [message #86953]

Mon, 16 December 2013 22:32

JP
Messages: 55
Registered: April 2008

Member

Hi IDLers,

I am currently using BVLS (http://www-astro.physics.ox.ac.uk/~mxc/idl/bvls.pro) for spectral unmixing. It works great, but, on one pixel at a time. I want to implement for many pixels without having to loop. Example below:

IDL> help, a
A FLOAT = Array[85, 3]
IDL> help, b
B FLOAT = Array[85]
IDL> help, bnd
BND FLOAT = Array[2, 3]
IDL> print, bnd
0.000000 1.00000
0.000000 1.00000
0.000000 1.00000

bvls, A, B, BND, X_BVLS

IDL> help, x_bvls
X_BVLS FLOAT = Array[3]

in my example A is a vector of "endmembers" (85 spectral bands and 3 fractions), B is a pixel (vector of 85 bands), BND are bounds (don't go negative nor >1) and the X_BVLS are the estimated fractions returned for that pixel.
Now as you could imagine I have many many pixels (n) (my B is really a 2D array of [85, n]) and i've written a function which loops through n, but it gets very slow for large n.

Any ideas?

Thanks

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[Message index]

		BVLS (NNLS) without loops? By: JP on Mon, 16 December 2013 22:32
		Re: BVLS (NNLS) without loops? By: Mike[5] on Tue, 17 December 2013 09:35
		Re: BVLS (NNLS) without loops? By: Mike[5] on Tue, 14 January 2014 07:42
		Re: BVLS (NNLS) without loops? By: JP on Tue, 14 January 2014 17:19

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