pith. sign in

arxiv: 2605.20770 · v1 · pith:VCH4XQGEnew · submitted 2026-05-20 · 🧮 math.NA · cs.NA

Data-informed posterior approximation for Bayesian linear inverse problems

Pith reviewed 2026-05-21 02:49 UTC · model grok-4.3

classification 🧮 math.NA cs.NA
keywords Bayesian inverse problemsposterior approximationdata-informed subspaceisometric embeddingGolub-Kahan bidiagonalizationempirical Bayesian inferenceKrylov subspacesmatrix-free methods
0
0 comments X

The pith

In Bayesian linear inverse problems the prior-to-posterior update is confined to an isometric embedding of a low-dimensional data space.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper develops a data-informed framework that moves the computational burden in large-scale Bayesian linear inverse problems from the high-dimensional parameter space to a much smaller data space. It rigorously shows that this data space is intrinsically low-dimensional, that it embeds isometrically into the parameter space, and that the entire prior-to-posterior update occurs inside the image of that embedding. Because the update is confined to this subspace, posterior inference can be performed in a reduced-dimensional setting rather than the full parameter space. The authors then build a matrix-free iterative procedure that constructs data-informed Krylov subspaces via quotient-space Golub-Kahan bidiagonalization while simultaneously estimating hyperparameters with empirical Bayes.

Core claim

We rigorously characterize an intrinsically low-dimensional data space, establish its isometric embedding into the parameter space, and show that the prior-to-posterior update is confined to a data-informed subspace. This perspective allows posterior inference to be carried out in a reduced data-informed subspace. Based on this formulation, we propose a quotient-space Golub-Kahan bidiagonalization method to construct data-informed Krylov subspaces, and integrate empirical Bayesian inference into the iterative framework, enabling simultaneous hyperparameter estimation and posterior approximation in a matrix-free manner.

What carries the argument

isometric embedding of the intrinsically low-dimensional data space into the parameter space that confines the prior-to-posterior update

Load-bearing premise

The data-informed subspace remains low-dimensional and the isometric embedding preserves the essential posterior information without significant truncation error.

What would settle it

A concrete numerical experiment in which the posterior mean or covariance obtained from the reduced data-informed subspace differs substantially from a reference posterior computed in the full parameter space would falsify the central claim.

Figures

Figures reproduced from arXiv: 2605.20770 by Haibo Li.

Figure 5.1
Figure 5.1. Figure 5.1: Illustration of the true solution and noisy observation data. [PITH_FULL_IMAGE:figures/full_fig_p020_5_1.png] view at source ↗
Figure 5.2
Figure 5.2. Figure 5.2: Eigenvalue decay of (M, Γ), reconstructed solution, and convergence behavior of the Q￾GKB method for the first example. relationship σ 2 = 1/λ, the Q-GKB based empirical Bayesian inference (QGKB-EB) method iteratively estimates the optimal hyperparameter λ, thereby obtaining an accurate estimate of σ, which is then be used to compute the posterior distribution. In [PITH_FULL_IMAGE:figures/full_fig_p021_… view at source ↗
Figure 5.3
Figure 5.3. Figure 5.3: The F¨orstner distance and the KL divergence between the exact and approximate posterior, [PITH_FULL_IMAGE:figures/full_fig_p022_5_3.png] view at source ↗
Figure 5.4
Figure 5.4. Figure 5.4: Contour plots of the marginal distributions of six randomly selected [PITH_FULL_IMAGE:figures/full_fig_p022_5_4.png] view at source ↗
Figure 5
Figure 5. Figure 5 [PITH_FULL_IMAGE:figures/full_fig_p023_5.png] view at source ↗
Figure 5.5
Figure 5.5. Figure 5.5: Illustration of the true image and noisy blurred image. [PITH_FULL_IMAGE:figures/full_fig_p023_5_5.png] view at source ↗
Figure 5.6
Figure 5.6. Figure 5.6: Eigenvalue decay of (M, Γ) and convergence behavior of the Q-GKB method for the first example [PITH_FULL_IMAGE:figures/full_fig_p024_5_6.png] view at source ↗
Figure 5.7
Figure 5.7. Figure 5.7: Illustration of the prior image, deblurred image at [PITH_FULL_IMAGE:figures/full_fig_p024_5_7.png] view at source ↗
Figure 5.8
Figure 5.8. Figure 5.8: The relative error of the approximate posterior mean and the corresponding mean standard [PITH_FULL_IMAGE:figures/full_fig_p025_5_8.png] view at source ↗
Figure 5
Figure 5. Figure 5 [PITH_FULL_IMAGE:figures/full_fig_p025_5.png] view at source ↗
Figure 5.9
Figure 5.9. Figure 5.9: Comparison of the running time for the Q-GKB method and LIS method as the iteration [PITH_FULL_IMAGE:figures/full_fig_p026_5_9.png] view at source ↗
Figure 5.10
Figure 5.10. Figure 5.10: Illustration of the true image and noisy observation data. [PITH_FULL_IMAGE:figures/full_fig_p027_5_10.png] view at source ↗
Figure 5.11
Figure 5.11. Figure 5.11: Evolution of the approximate posterior mean and variance during the Q-GKB iteration. [PITH_FULL_IMAGE:figures/full_fig_p028_5_11.png] view at source ↗
Figure 5.12
Figure 5.12. Figure 5.12: Illustration of the prior image, reconstructed image, and corresponding pixel-wise variance [PITH_FULL_IMAGE:figures/full_fig_p028_5_12.png] view at source ↗
read the original abstract

Computing posterior distributions in large-scale Bayesian linear inverse problems is challenging due to the high dimensionality of the parameter space. In this work, we develop a data-informed framework that shifts the computational focus from the parameter space to the data space. We rigorously characterize an intrinsically low-dimensional data space, establish its isometric embedding into the parameter space, and show that the prior-to-posterior update is confined to a data-informed subspace. This perspective allows posterior inference to be carried out in a reduced data-informed subspace. Based on this formulation, we propose a quotient-space Golub--Kahan bidiagonalization method to construct data-informed Krylov subspaces, and integrate empirical Bayesian inference into the iterative framework, enabling simultaneous hyperparameter estimation and posterior approximation in a matrix-free manner. Numerical experiments on representative problems support the theoretical framework and demonstrate the effectiveness of the resulting method.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The paper develops a data-informed framework for posterior approximation in large-scale Bayesian linear inverse problems. It rigorously characterizes an intrinsically low-dimensional data space, establishes its isometric embedding into the parameter space, and shows that the prior-to-posterior update is confined to this data-informed subspace. Based on this, the authors propose a quotient-space Golub-Kahan bidiagonalization method to build data-informed Krylov subspaces and integrate empirical Bayesian inference for simultaneous hyperparameter estimation and matrix-free posterior approximation. Numerical experiments on representative problems are included to support the claims.

Significance. If the theoretical characterization and isometric embedding hold under the paper's assumptions, the work offers a promising shift from high-dimensional parameter space to lower-dimensional data space for Bayesian inverse problems, potentially improving scalability in applications such as imaging or parameter estimation. The matrix-free iterative approach combined with empirical Bayes is a practical strength, and the numerical results indicate effectiveness. Explicit error bounds or operator conditions would further strengthen the significance.

major comments (2)
  1. [Theoretical framework] Theoretical framework section: The central claim that the data-informed subspace remains intrinsically low-dimensional and that the isometric embedding preserves essential posterior information without significant truncation error lacks explicit bounds, singular-value decay assumptions on the forward map, or discretization conditions. This is load-bearing for the applicability to the target class of inverse problems, as the abstract and framework rely on it for the reduced-space inference.
  2. [Quotient-space Golub-Kahan bidiagonalization] Section on the quotient-space Golub-Kahan bidiagonalization: The construction of data-informed Krylov subspaces via the quotient-space method requires clarification on how the isometry is maintained during iteration and whether truncation in the bidiagonalization introduces errors that propagate to the posterior approximation; this directly affects the matrix-free claim.
minor comments (2)
  1. [Abstract] Abstract: The description of numerical experiments could briefly note the specific inverse problems considered (e.g., dimensions or forward operators) to better contextualize the support for the theoretical framework.
  2. [Notation and definitions] Notation: Ensure consistent use of symbols for the data-informed subspace and embedding operator across sections to avoid potential confusion in the reduced-space formulation.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive and detailed report. We address each major comment point by point below, indicating the revisions we will make to strengthen the manuscript.

read point-by-point responses
  1. Referee: [Theoretical framework] Theoretical framework section: The central claim that the data-informed subspace remains intrinsically low-dimensional and that the isometric embedding preserves essential posterior information without significant truncation error lacks explicit bounds, singular-value decay assumptions on the forward map, or discretization conditions. This is load-bearing for the applicability to the target class of inverse problems, as the abstract and framework rely on it for the reduced-space inference.

    Authors: We agree that the manuscript would benefit from more explicit quantitative statements. The current theoretical framework characterizes the data-informed subspace as the range of the adjoint of the forward operator composed with the prior covariance and establishes the isometric embedding via the inner-product structure induced by the prior. However, we acknowledge that explicit a priori error bounds in terms of singular-value decay and discretization error estimates are not stated. In the revised manuscript we will add a new subsection containing such bounds under standard assumptions on the decay of the singular values of the discretized forward map and on the mesh size. This will make the load-bearing claims fully quantitative while preserving the matrix-free character of the method. revision: yes

  2. Referee: [Quotient-space Golub-Kahan bidiagonalization] Section on the quotient-space Golub-Kahan bidiagonalization: The construction of data-informed Krylov subspaces via the quotient-space method requires clarification on how the isometry is maintained during iteration and whether truncation in the bidiagonalization introduces errors that propagate to the posterior approximation; this directly affects the matrix-free claim.

    Authors: We appreciate the request for clarification. The quotient-space formulation performs the bidiagonalization entirely in the data space; the isometry is maintained at every step by construction because the inner products are taken with respect to the data-space metric induced by the noise covariance and the prior is used only to map the resulting basis vectors back to the parameter space via the adjoint operator. Truncation after k steps produces a rank-k approximation whose error is controlled by the residual of the bidiagonalization process. In the revised version we will insert a short paragraph (and, if space permits, a brief lemma) that explicitly states how the isometry is preserved iteration by iteration and that bounds the propagation of the truncation error into the posterior covariance and mean. These additions will also reinforce the matrix-free nature of the overall algorithm. revision: yes

Circularity Check

0 steps flagged

No significant circularity; framework builds on standard linear algebra and Bayesian tools

full rationale

The paper's central claims involve characterizing a low-dimensional data space and its isometric embedding into parameter space for Bayesian linear inverse problems, using quotient-space Golub-Kahan bidiagonalization and empirical Bayesian inference. These steps rely on established operator theory, Krylov subspace methods, and standard Bayesian updating without reducing any prediction or result to a fitted parameter or self-citation by construction. The abstract and framework present the low-dimensionality as a rigorous characterization under typical assumptions on the forward map, not as a tautology or renamed input. No load-bearing step equates outputs to inputs via definition or self-referential fitting. Minor self-citation risk exists in any iterative method paper but is not central here. Derivation remains self-contained against external benchmarks like standard SVD-based dimension reduction.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The central claim rests on the existence of an intrinsically low-dimensional data space whose isometric embedding confines the prior-to-posterior update; these are presented as rigorously established but their precise mathematical assumptions are not visible in the abstract.

axioms (2)
  • domain assumption The data space is intrinsically low-dimensional for the class of linear inverse problems considered
    Abstract states 'rigorously characterize an intrinsically low-dimensional data space'
  • domain assumption An isometric embedding of the data space into the parameter space exists and preserves the update
    Abstract claims 'establish its isometric embedding into the parameter space'

pith-pipeline@v0.9.0 · 5661 in / 1388 out tokens · 30491 ms · 2026-05-21T02:49:49.826194+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

48 extracted references · 48 canonical work pages

  1. [1]

    Extreme-scale UQ for Bayesian inverse problems governed by PDEs

    Tan Bui-Thanh, Carsten Burstedde, Omar Ghattas, James Martin, Georg Stadler, and Lucas C Wilcox. Extreme-scale UQ for Bayesian inverse problems governed by PDEs. InSC’12: Pro- ceedings of the international conference on high performance computing, networking, storage and analysis, pages 1–11. IEEE, 2012

  2. [2]

    Tan Bui-Thanh, Omar Ghattas, James Martin, and Georg Stadler. A computational framework for infinite-dimensional Bayesian inverse problems part I: The linearized case, with application to global seismic inversion.SIAM Journal on Scientific Computing, 35(6):A2494–A2523, 2013. 30

  3. [3]

    Springer, 2008

    Thorsten Buzug.Computed Tomography. Springer, 2008

  4. [4]

    London: Chapman and Hall, 1997

    Bradley P Carlin and Thomas A Louis.Bayes and empirical Bayes methods for data analysis. London: Chapman and Hall, 1997

  5. [5]

    Convergence analysis of LSQR for compact operator equations.Linear Algebra and its Applications, 583:146–164, 2019

    Noe Angelo Caruso and Paolo Novati. Convergence analysis of LSQR for compact operator equations.Linear Algebra and its Applications, 583:146–164, 2019

  6. [6]

    Generalized hybrid iterative methods for large-scale Bayesian inverse problems.SIAM Journal on Scientific Computing, 39(5):S24–S46, 2017

    J Chung and A K Saibaba. Generalized hybrid iterative methods for large-scale Bayesian inverse problems.SIAM Journal on Scientific Computing, 39(5):S24–S46, 2017

  7. [7]

    Computational methods for large-scale inverse problems: a survey on hybrid projection methods.SIAM Review, 66(2):205–284, 2024

    Julianne Chung and Silvia Gazzola. Computational methods for large-scale inverse problems: a survey on hybrid projection methods.SIAM Review, 66(2):205–284, 2024

  8. [8]

    A weighted-GCV method for Lanczos- hybrid regularization.Electr

    Julianne Chung, James G Nagy, and Dianne P O’Leary. A weighted-GCV method for Lanczos- hybrid regularization.Electr. Trans. Numer. Anal., 28(29):149–167, 2008

  9. [9]

    Likelihood-informed dimension reduction for nonlinear inverse problems.Inverse Problems, 30 (11):114015, 2014

    Tiangang Cui, James Martin, Youssef M Marzouk, Antti Solonen, and Alessio Spantini. Likelihood-informed dimension reduction for nonlinear inverse problems.Inverse Problems, 30 (11):114015, 2014

  10. [10]

    Map estimators and their consistency in Bayesian nonparametric inverse problems.Inverse Problems, 29(9):095017, 2013

    Masoumeh Dashti, Kody JH Law, Andrew M Stuart, and Jochen Voss. Map estimators and their consistency in Bayesian nonparametric inverse problems.Inverse Problems, 29(9):095017, 2013

  11. [11]

    H. W. Engl, M Hanke, and A Neubauer.Regularization of Inverse Problems. Kluwer Academic Publishers, 2000

  12. [12]

    H Pearl Flath, Lucas C Wilcox, Volkan Ak¸ celik, Judith Hill, Bart van Bloemen Waanders, and Omar Ghattas. Fast algorithms for Bayesian uncertainty quantification in large-scale linear in- verse problems based on low-rank partial hessian approximations.SIAM Journal on Scientific Computing, 33(1):407–432, 2011

  13. [13]

    A metric for covariance matrices

    Wolfgang F¨ orstner and Boudewijn Moonen. A metric for covariance matrices. InGeodesy-the Challenge of the 3rd Millennium, pages 299–309. Springer, 2003

  14. [14]

    Well-posed stochastic extensions of ill-posed linear problems.Journal of mathe- matical analysis and applications, 31(3):682–716, 1970

    Joel N Franklin. Well-posed stochastic extensions of ill-posed linear problems.Journal of mathe- matical analysis and applications, 31(3):682–716, 1970

  15. [15]

    IR Tools: A MATLAB package of iterative regularization methods and large-scale test problems.Numerical Algorithms, 81(3):773– 811, 2019

    Silvia Gazzola, Per Christian Hansen, and James G Nagy. IR Tools: A MATLAB package of iterative regularization methods and large-scale test problems.Numerical Algorithms, 81(3):773– 811, 2019

  16. [16]

    SIAM, 2010

    Per Christian Hansen.Discrete inverse problems: insight and algorithms. SIAM, 2010

  17. [17]

    SIAM, Philadelphia, 2006

    Per Christian Hansen, J G Nagy, and D P O’Leary.Deblurring Images: Matrices, Spectra and Filtering. SIAM, Philadelphia, 2006

  18. [18]

    Maximum a posteriori probability estimates in infinite- dimensional Bayesian inverse problems.Inverse Problems, 31(8):085009, 2015

    Tapio Helin and Martin Burger. Maximum a posteriori probability estimates in infinite- dimensional Bayesian inverse problems.Inverse Problems, 31(8):085009, 2015

  19. [19]

    Cambridge University Press, 2012

    Roger A Horn and Charles R Johnson.Matrix Analysis. Cambridge University Press, 2012

  20. [20]

    Springer, 2006

    Jari Kaipio and Erkki Somersalo.Statistical and Computational Inverse Problems. Springer, 2006

  21. [21]

    ¨Uber lineare methoden in der wahrscheinlichkeitsrechnung.Ann Acad Sci Fen- nicae, 37:1, 1947

    Kari Karhunen. ¨Uber lineare methoden in der wahrscheinlichkeitsrechnung.Ann Acad Sci Fen- nicae, 37:1, 1947

  22. [22]

    Choosing regularization parameters in iterative methods for ill-posed problems.SIAM Journal on Matrix Analysis and Applications, 22(4):1204–1221, 2001

    Misha E Kilmer and Dianne P O’Leary. Choosing regularization parameters in iterative methods for ill-posed problems.SIAM Journal on Matrix Analysis and Applications, 22(4):1204–1221, 2001

  23. [23]

    Springer, 2015

    Konstantinos Zygalakis Kody Law, Andrew Stuart.Data Assimilation: A Mathematical Intro- duction. Springer, 2015

  24. [24]

    Linear inverse problems for generalised random variables.Inverse problems, 5(4):599–612, 1989

    Markku S Lehtinen, Lassi Paivarinta, and Erkki Somersalo. Linear inverse problems for generalised random variables.Inverse problems, 5(4):599–612, 1989

  25. [25]

    A preconditioned Krylov subspace method for linear inverse problems with general-form Tikhonov regularization.SIAM Journal on Scientific Computing, 46(4):A2607–A2633, 2024

    Haibo Li. A preconditioned Krylov subspace method for linear inverse problems with general-form Tikhonov regularization.SIAM Journal on Scientific Computing, 46(4):A2607–A2633, 2024. 31

  26. [26]

    Projected Newton method for large-scale Bayesian linear inverse problems.SIAM Journal on Optimization, 35(3):1439–1468, 2025

    Haibo Li. Projected Newton method for large-scale Bayesian linear inverse problems.SIAM Journal on Optimization, 35(3):1439–1468, 2025

  27. [27]

    Efficient geostatistical inverse methods for structured and unstructured grids.Water resources research, 42(6), 2006

    Wei Li and Olaf A Cirpka. Efficient geostatistical inverse methods for structured and unstructured grids.Water resources research, 42(6), 2006

  28. [28]

    Parameter and state model reduction for large-scale statistical inverse problems.SIAM Journal on Scientific Computing, 32(5):2523–2542, 2010

    Chad Lieberman, Karen Willcox, and Omar Ghattas. Parameter and state model reduction for large-scale statistical inverse problems.SIAM Journal on Scientific Computing, 32(5):2523–2542, 2010

  29. [29]

    Numerical Mathematics and Scie, 2013

    J¨ org Liesen and Zdenek Strakos.Krylov subspace methods: principles and analysis. Numerical Mathematics and Scie, 2013

  30. [30]

    Finn Lindgren, H˚ avard Rue, and Johan Lindstr¨ om. An explicit link between Gaussian fields and Gaussian Markov random fields: the stochastic partial differential equation approach.Journal of the Royal Statistical Society Series B: Statistical Methodology, 73(4):423–498, 2011

  31. [31]

    Lo` eve.Probability Theory II

    M. Lo` eve.Probability Theory II. Springer New York, NY, 1978

  32. [32]

    A stochastic Newton MCMC method for large-scale statistical inverse problems with application to seismic inversion

    James Martin, Lucas C Wilcox, Carsten Burstedde, and Omar Ghattas. A stochastic Newton MCMC method for large-scale statistical inverse problems with application to seismic inversion. SIAM Journal on Scientific Computing, 34(3):A1460–A1487, 2012

  33. [33]

    Dimensionality reduction and polynomial chaos ac- celeration of Bayesian inference in inverse problems.Journal of Computational Physics, 228(6): 1862–1902, 2009

    Youssef M Marzouk and Habib N Najm. Dimensionality reduction and polynomial chaos ac- celeration of Bayesian inference in inverse problems.Journal of Computational Physics, 228(6): 1862–1902, 2009

  34. [34]

    SIAM, 2001

    Frank Natterer.The Mathematics of Computerized Tomography. SIAM, 2001

  35. [35]

    Efficient computation of linearized cross- covariance and auto-covariance matrices of interdependent quantities.Mathematical geology, 35 (1):53–66, 2003

    Wolfgang Nowak, Sascha Tenkleve, and Olaf A Cirpka. Efficient computation of linearized cross- covariance and auto-covariance matrices of interdependent quantities.Mathematical geology, 35 (1):53–66, 2003

  36. [36]

    Bayes and empirical Bayes: do they merge? Biometrika, pages 285–302, 2014

    Sonia Petrone, Judith Rousseau, and Catia Scricciolo. Bayes and empirical Bayes: do they merge? Biometrika, pages 285–302, 2014

  37. [37]

    Hybrid and iteratively reweighted regularization by unbiased predictive risk and weighted GCV for projected systems.SIAM Journal on Scientific Computing, 39(2):B221–B243, 2017

    R A Renaut, S Vatankhah, and V E Ardesta. Hybrid and iteratively reweighted regularization by unbiased predictive risk and weighted GCV for projected systems.SIAM Journal on Scientific Computing, 39(2):B221–B243, 2017

  38. [38]

    Springer, 2016

    Mathias Richter.Inverse Problems: Basics, Theory and Applications in Geophysics. Springer, 2016

  39. [39]

    Whittle-Mat´ ern priors for bayesian statistical inversion with applications in electrical impedance tomography.Inverse Probl

    Lassi Roininen, Janne MJ Huttunen, and Sari Lasanen. Whittle-Mat´ ern priors for bayesian statistical inversion with applications in electrical impedance tomography.Inverse Probl. Imag., 8(2), 2014

  40. [40]

    Asymptotic behaviour of the empirical Bayes posteriors associated to maximum marginal likelihood estimator.Annals of Statistics, 2017

    Judith Rousseau and Botond Szabo. Asymptotic behaviour of the empirical Bayes posteriors associated to maximum marginal likelihood estimator.Annals of Statistics, 2017

  41. [41]

    SIAM, 2011

    Yousef Saad.Numerical methods for large eigenvalue problems: revised edition. SIAM, 2011

  42. [42]

    Efficient Krylov subspace methods for uncertainty quantification in large Bayesian linear inverse problems.Numer

    Arvind K Saibaba, Julianne Chung, and Katrina Petroske. Efficient Krylov subspace methods for uncertainty quantification in large Bayesian linear inverse problems.Numer. Linear Algebra Appl., 27(5):e2325, 2020

  43. [43]

    Optimal low-rank approximations of Bayesian linear inverse problems.SIAM Journal on Scientific Computing, 37(6):A2451–A2487, 2015

    Alessio Spantini, Antti Solonen, Tiangang Cui, James Martin, Luis Tenorio, and Youssef Marzouk. Optimal low-rank approximations of Bayesian linear inverse problems.SIAM Journal on Scientific Computing, 37(6):A2451–A2487, 2015

  44. [44]

    Goal-oriented optimal approximations of bayesian linear inverse problems.SIAM Journal on Scientific Com- puting, 39(5):S167–S196, 2017

    Alessio Spantini, Tiangang Cui, Karen Willcox, Luis Tenorio, and Youssef Marzouk. Goal-oriented optimal approximations of bayesian linear inverse problems.SIAM Journal on Scientific Com- puting, 39(5):S167–S196, 2017

  45. [45]

    Inverse problems: a Bayesian perspective.Acta Numerica, 19:451–559, 2010

    Andrew M Stuart. Inverse problems: a Bayesian perspective.Acta Numerica, 19:451–559, 2010

  46. [46]

    Washington, DC, 1977

    A N Tikhonov and V Y Arsenin.Solutions of Ill-Posed Problems. Washington, DC, 1977. 32

  47. [47]

    MIT press Cambridge, MA, 2006

    Christopher KI Williams and Carl Edward Rasmussen.Gaussian processes for machine learning. MIT press Cambridge, MA, 2006

  48. [48]

    Simulation of stationary Gaussian processes in [0,1]d.Journal of computational and graphical statistics, 3(4):409–432, 1994

    Andrew TA Wood and Grace Chan. Simulation of stationary Gaussian processes in [0,1]d.Journal of computational and graphical statistics, 3(4):409–432, 1994. 33