39 citations · 104 across the 19 of their papers we have counts for
19 papers
Implications of Clinical Target Distribution Weighted Radiotherapy Optimization
Ivar Bengtsson, Anders Forsgren, Albin Fredriksson
Delineating and planning with respect to regions suspected to contain microscopic tumor cells is an inherently uncertain task in radiotherapy. The recently proposed \textit{clinica…
Quasi-Newton methods for minimizing a quadratic function subject to uncertainty
Shen Peng, Gianpiero Canessa, David Ek +1
We investigate quasi-Newton methods for minimizing a strictly convex quadratic function which is subject to errors in the evaluation of the gradients. The methods all give identica…
An optimization derivation of the method of conjugate gradients
David Ek, Anders Forsgren
We give a derivation of the method of conjugate gradients based on the requirement that each iterate minimizes a strictly convex quadratic on the space spanned by the previously ob…
A structured modified Newton approach for solving systems of nonlinear equations arising in interior-point methods for quadratic programming
David Ek, Anders Forsgren
The focus in this work is on interior-point methods for inequality-constrained quadratic programs, and particularly on the system of nonlinear equations to be solved for each value…
Approximate solution of system of equations arising in interior-point methods for bound-constrained optimization
David Ek, Anders Forsgren
The focus in this paper is interior-point methods for bound-constrained nonlinear optimization, where the system of nonlinear equations that arise are solved with Newton's method.…
On the existence of a short pivoting sequence for a linear program
Anders Forsgren, Fei Wang
Pivoting methods are of vital importance for linear programming, the simplex method being the by far most well-known. In this paper, a primal-dual pair of linear programs in canoni…
On the Interplay between Robustness and Dynamic Planning for Adaptive Radiation Therapy
Michelle Böck, Kjell Eriksson, Anders Forsgren
Interfractional geometric uncertainties can lead to deviations of the actual delivered dose from the prescribed dose distribution. To better handle these uncertainties during treat…
On tradeoffs between treatment time and plan quality of volumetric-modulated arc therapy with sliding-window delivery
Lovisa Engberg, Anders Forsgren
The purpose of this study is to give an exact formulation of optimization of volumetric-modulated arc therapy (VMAT) with sliding-window delivery, and to investigate the plan quali…
Exact linesearch limited-memory quasi-Newton methods for minimizing a quadratic function
David Ek, Anders Forsgren
The main focus in this paper is exact linesearch methods for minimizing a quadratic function whose Hessian is positive definite. We give a class of limited-memory quasi-Newton Hess…
Increased accuracy of planning tools for optimization of dynamic multileaf collimator delivery of radiotherapy through reformulated objective functions
Lovisa Engberg, Kjell Eriksson, Anders Forsgren
The purpose of this study is to examine in a clinical setting a novel formulation of objective functions for intensity-modulated radiotherapy treatment plan multicriteria optimizat…
Towards Robust Adaptive Radiation Therapy Strategies
Michelle Böck, Anders Forsgren, Kjell Eriksson +1
The authors propose robust adaptive strategies based on stochastic minimax optimization for a series of simulated treatments on a one-dimensional patient phantom. The plan applied…
Explicit optimization of plan quality measures in intensity-modulated radiation therapy treatment planning
Lovisa Engberg, Kjell Eriksson, Anders Forsgren +1
Conventional planning objectives in optimization of intensity-modulated radiotherapy treatment (IMRT) plans are designed to minimize the violation of dose-volume histogram (DVH) th…
Robust generation of elementary flux modes
Hildur Æsa Oddsdóttir, Erika Hagrot, Veronique Chotteau +1
Elementary flux modes (EFMs) are vectors defined from a metabolic reaction network, giving the connections between substrates and products. EFMs-based metabolic flux analysis (MFA)…
Primal and dual active-set methods for convex quadratic programming
Anders Forsgren, Philip E. Gill, Elizabeth Wong
Computational methods are proposed for solving a convex quadratic program (QP). Active-set methods are defined for a particular primal and dual formulation of a QP with general equ…
On exact linesearch quasi-Newton methods for minimizing a quadratic function
Anders Forsgren, Tove Odland
This paper concerns exact linesearch quasi-Newton methods for minimizing a quadratic function whose Hessian is positive definite. We show that by interpreting the method of conjuga…
On Dynamically Generating Relevant Elementary Flux Modes in a Metabolic Network using Optimization
Hildur Æsa Oddsdóttir, Erika Hagrot, Véronique Chotteau +1
Elementary flux modes (EFMs) are pathways through a metabolic reaction network that connect external substrates to products. Using EFMs, a metabolic network can be transformed into…
On solving symmetric systems of linear equations in an unnormalized Krylov subspace framework
Anders Forsgren, Tove Odland
In an unnormalized Krylov subspace framework for solving symmetric systems of linear equations, the orthogonal vectors that are generated by a Lanczos process are not necessarily o…
On the connection between the conjugate gradient method and quasi-Newton methods on quadratic problems
Anders Forsgren, Tove Odland
It is well known that the conjugate gradient method and a quasi-Newton method, using any well-defined update matrix from the one-parameter Broyden family of updates, produce identi…
An elementary proof of linear programming optimality conditions without using Farkas' lemma
Anders Forsgren, Margaret H. Wright
Although it is easy to prove the sufficient conditions for optimality of a linear program, the necessary conditions pose a pedagogical challenge. A widespread practice in deriving…