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 Post subject: C=LDL^(-1). Find an expression for C^(-1).Posted: Wed, 15 Feb 2012 09:23:22 UTC
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C=LDL^(-1). Find an expression for C^(-1), in terms of L, its inverse and some diagonal matrix

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 Post subject: Re: C=LDL^(-1). Find an expression for C^(-1).Posted: Wed, 15 Feb 2012 14:35:24 UTC
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C=LDL^(-1). Find an expression for C^(-1), in terms of L, its inverse and some diagonal matrix

Socks and shoes?

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"Mathematicians are like lovers. Grant a mathematician the least principle, and he will draw from it a consequence which you must also grant him, and from this consequence another." Bernard Le Bovier Fontenelle (1657-1757)

"In great mathematics there is a very high degree of unexpectedness, combined with inevitability and economy."
G.H. Hardy (1877-1947)

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 Post subject: Re: C=LDL^(-1). Find an expression for C^(-1).Posted: Wed, 15 Feb 2012 15:10:54 UTC
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Joined: Wed, 30 Mar 2005 04:25:14 UTC
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Location: Austin, TX
Justin wrote:
C=LDL^(-1). Find an expression for C^(-1), in terms of L, its inverse and some diagonal matrix

Socks and shoes?

What?

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 Post subject: Re: C=LDL^(-1). Find an expression for C^(-1).Posted: Wed, 15 Feb 2012 15:11:55 UTC
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Location: Austin, TX
C=LDL^(-1). Find an expression for C^(-1), in terms of L, its inverse and some diagonal matrix

may or may not exist depending on the diagonal matrix, . Assuming is invertible, then you just need to invert both sides and recall that

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 Post subject: Re: C=LDL^(-1). Find an expression for C^(-1).Posted: Thu, 16 Feb 2012 15:29:46 UTC
 Member of the 'S.O.S. Math' Hall of Fame

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C=LDL^(-1). Find an expression for C^(-1), in terms of L, its inverse and some diagonal matrix

may or may not exist depending on the diagonal matrix, . Assuming is invertible, then you just need to invert both sides and recall that

Like I said, "socks and shoes". I didn't want to do all the work for them!

_________________
"Mathematicians are like lovers. Grant a mathematician the least principle, and he will draw from it a consequence which you must also grant him, and from this consequence another." Bernard Le Bovier Fontenelle (1657-1757)

"In great mathematics there is a very high degree of unexpectedness, combined with inevitability and economy."
G.H. Hardy (1877-1947)

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 Post subject: Re: C=LDL^(-1). Find an expression for C^(-1).Posted: Thu, 16 Feb 2012 21:26:43 UTC
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Joined: Wed, 30 Mar 2005 04:25:14 UTC
Posts: 12074
Location: Austin, TX
Justin wrote:
C=LDL^(-1). Find an expression for C^(-1), in terms of L, its inverse and some diagonal matrix

may or may not exist depending on the diagonal matrix, . Assuming is invertible, then you just need to invert both sides and recall that

Like I said, "socks and shoes". I didn't want to do all the work for them!

I don't get it, but OK.

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 Post subject: Re: C=LDL^(-1). Find an expression for C^(-1).Posted: Fri, 2 Mar 2012 17:52:23 UTC
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Joined: Tue, 20 Oct 2009 18:18:45 UTC
Posts: 33
Location: Lisbon, Portugal
when you dress: 1st, socks; 2nd shoes
when you undress («inverse»): 1st shoes, 2nd socks...
it's funny
Cheers
Voxx

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 Post subject: Re: C=LDL^(-1). Find an expression for C^(-1).Posted: Fri, 2 Mar 2012 17:56:33 UTC
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Joined: Wed, 30 Mar 2005 04:25:14 UTC
Posts: 12074
Location: Austin, TX
Voxx wrote:
when you dress: 1st, socks; 2nd shoes
when you undress («inverse»): 1st shoes, 2nd socks...
it's funny
Cheers
Voxx

Ahhh, I see. Well put Voxx.

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