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Changes between Version 4 and Version 5 of BysVecLinReg


Ignore:
Timestamp:
May 6, 2010, 5:10:01 PM (15 years ago)
Author:
Víctor de Buen Remiro
Comment:

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  • BysVecLinReg

    v4 v5  
    11= TOL Package BysVecLinReg =
    22
    3 BysVecLinReg yields for Bayesian simulator of Vectorial Linear Regression with arbitrary constraining inequations
     3BysVecLinReg yields for Bayesian simulator of Vectorial Linear Regression with
     4arbitrary constraining inequations.
     5
     6The method used in this package is based on [https://www.tol-project.org/export/HEAD/tolp/trunk/tol_pkg/BysVecLinReg/doc/bayes-linear-minka.pdf  Bayesian linear regression Thomas Minka (2001)] using invariant scale prior over [[LatexEquation(A)]] and inverse prior over [[LatexEquation(V)]]
    47
    58Vectorial linear regression equations are [[BR]]
     
    912where [[BR]]
    1013
    11  * [[LatexEquation(Y\in\mathbb{R}^{d\times N} )]] is the multivariant known output matrix, where each row is a different output vector [[LatexEquation(y_{n}\in\mathbb{R}^{N} )]]  [[BR]]
    12  * [[LatexEquation(X\in\mathbb{R}^{m\times N} )]] is the known and full rank input matrix, where each row is a different input vector [[LatexEquation(x_{n}\in\mathbb{R}^{N} )]] [[BR]]
    13  * [[LatexEquation(A\in\mathbb{R}^{d\times m} )]] has the unknown regression coefficients that we want to estimate [[BR]]
    14  * [[LatexEquation(E\in\mathbb{R}^{d\times N} )]] is the multivariant residuals, where each row is the residuals vector  [[LatexEquation(e_{n}\in\mathbb{R}^{N} )]] corresponding to output [[LatexEquation(y_{n} )]]
     14 * [[LatexEquation(Y\in\mathbb{R}^{d\times N} )]] is the multivariant known
     15   output matrix, where each row is a different output vector
     16   [[LatexEquation(y_{n}\in\mathbb{R}^{N} )]][[BR]]
     17 * [[LatexEquation(X\in\mathbb{R}^{m\times N} )]] is the known and full rank
     18   input matrix, where each row is a different input vector
     19   [[LatexEquation(x_{n}\in\mathbb{R}^{N} )]] [[BR]]
     20 * [[LatexEquation(A\in\mathbb{R}^{d\times m} )]] has the unknown regression
     21   coefficients that we want to estimate [[BR]]
     22 * [[LatexEquation(E\in\mathbb{R}^{d\times N} )]] is the multivariant
     23   residuals, where each row is the residuals vector
     24   [[LatexEquation(e_{n}\in\mathbb{R}^{N} )]] corresponding to output
     25   [[LatexEquation(y_{n} )]]
    1526 
    16 All residuals inside the same row are incorrelated normal, but resiudals in the same column [[LatexEquation(j)]] are [[BR]]
     27All residuals inside the same row are incorrelated normal, but resiudals in
     28the same column [[LatexEquation(j)]] are [[BR]]
    1729
    1830[[LatexEquation(e_{.,j} \sim N\left(0,V\right) E\in\mathbb{R}^{d\times d} \forall j=1 \ldots d )]][[BR]]
    1931
    20 where [[LatexEquation(V)]] is symmetric positive definite and unknown, but the same for each column.[[BR]]
     32where [[LatexEquation(V)]] is symmetric positive definite and unknown, but the
     33same for each column.[[BR]]
    2134
    22 When there are some restriction over parameters inside [[LatexEquation(A)]] we must to add the inequations of feasible region [[BR]]
     35Minka defines also the known data pair [[LatexEquation(D = left(Y,Xright))]]
     36that will be used just to get more compact conditioninig expressions.
     37 
     38We will extend the model scope with arbitrary non null meassured restrictions
     39over parameters inside [[LatexEquation(A)]] by means of adding a set of
     40[[LatexEquation(r)]] inequations defining a feasible region [[BR]]
    2341
    2442[[LatexEquation(\Omega = \left\{ A\in\mathbb{R}^{d\times m} \mid F\left(A\right) \le 0 \right\})]] [[BR]]
     
    3048the arbitrary constraining function. [[BR]]
    3149
    32 The method used in this package is based on [https://www.tol-project.org/export/HEAD/tolp/trunk/tol_pkg/BysVecLinReg/doc/bayes-linear-minka.pdf  Bayesian linear regression Thomas Minka (2001)] using invariant scale prior over [[LatexEquation(A)]] and inverse prior over [[LatexEquation(V)]]
     50Although Minka not explicitly stated in any place, under the invariant prior
     51follows that [[LatexEquation(X)]] must be full-range [[LatexEquation(m <= N)]]
     52because [[LatexEquation(X W X ^ T)]] must be nonsingular with
     53[[LatexEquation(W = \alpha I_{m})]], where [[LatexEquation(\alpha)]] is the
     54scale-invariant parameter governing the prior and estimated more
     55forward to maximize the evidence of the data, which depends on the assumptions
     56the model.