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CCA (Computational Convex Analysis) >> pl > pl_lft_direct_d

pl_lft_direct_d

[For comparison only] Legendre-Fenchel conjugate, direct computation on {1,...,n}

Calling Sequence

Conj = pl_lft_direct_d(Y)

Parameters

Y

column vector. The value of the function on the grid {1,...,n}: usually Y(i)=f(i) for some function f, with 1 <= i <= n and n=length(Y).

Conj

column vector. Contains the value of the conjugate f* of the function f evaluated at the points j. In other words: Conj(j) = Max(j * i - Y(i) | over all indexes i).

Description

Warning: This function is provided only for comparison purposes and unit testing, use the more efficient pl_lft_llt_d for faster computation.

Wrap over for easier computation of distance transforms. The function calls pl_lft_direct(X,Y,S) with n=length(Y), X=(1:1:n)' and S=X. See pl_lft_direct for more information.

Examples

row = [1 2.5 5 8.5 13]';
conj_part = -1.*pl_lft_direct_d(row);
b = isequal(conj_part, [0 -1.5 -4 -7.5 -12]');

See Also

Authors

Yves Lucet, University of British Columbia, BC, Canada

Used Functions

pl_lft_direct

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