28 lines
415 B
Mathematica
28 lines
415 B
Mathematica
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function [v,beta] = householder(x)
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% householder takes vertical vector x
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if ~iscolumn(x)
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x = x.';
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end
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n = length(x);
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sig = x(2:n).' * x(2:n);
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v = [1;
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x(2:n)];
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if isempty(sig) || (sig == 0)
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beta = 0;
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else
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mu = sqrt(x(1)^2+sig);
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if x(1) <= 0
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v(1) = x(1) - mu;
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else
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v(1) = -sig/(x(1) + mu);
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end
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beta = 2*v(1)^2/(sig + v(1)^2);
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v = v/v(1);
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end
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end
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