Namur Institute for Complex Systems

  • 5000

    Belgium

Research Output 1977 2018

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Working paper
2018

Minimizing convex quadratics with variable precision Krylov methods

Gratton, S., Simon, E. & Toint, P. 2018 (Submitted) Arxiv, 26 p.

Research output: Working paper

File
Krylov Methods
Quadratic Optimization
Cross product
Matrix Product
Conjugate Gradient
2017

A note on using performance and data profiles for training algorithms

Porcelli, M. & Toint, P. 26 Nov 2017 (Submitted) Arxiv, 8 p.(naXys technical report)

Research output: Working paper

File
Training Algorithm
Benchmarking
Derivatives
Derivative-free
Profile
File
Function evaluation
Unconstrained Optimization
Adaptive algorithms
Nonlinear Optimization
Tensors

On the use of the saddle formulation in weakly-constrained 4D-VAR data assimilation

Gratton, S., Gürol, S., Simon, E. & Toint, P. 20 Sep 2017 (Submitted) Arxiv

Research output: Working paper

File
Data Assimilation
Saddle
Parallel processing systems
data assimilation
parallel computing
File
Nonconvex Optimization
Constrained optimization
Constrained Optimization
Optimality
Criticality
File
Constrained optimization
Constrained Optimization
Singularity
Objective function
Regularization

Worst-case evaluation complexity and optimality of second-order methods for nonconvex smooth optimization

Cartis, C., Gould, N. I. M. & Toint, P. 22 Sep 2017 Arxiv, 35 p.

Research output: Working paper

File
Newton-Raphson method
Optimality
Optimization
Function evaluation
Evaluation
2016

Quantifying the degree of average contraction of Collatz orbits

Carletti, T. & Fanelli, D. 21 Dec 2016 (Submitted) Namur center for complex systems, 18 p.

Research output: Working paper

File
Contraction
Orbit
Modulo
Integer
Iterate
2015

Evaluation complexity bounds for smooth constrained nonlinear optimization using scaled KKT conditions and high-order models

Cartis, C., Gould, N. I. M. & Toint, P. 17 Oct 2015 (Submitted) Namur center for complex systems, 20 p.(naXys technical report)

Research output: Working paper

File
KKT Conditions
Constrained Optimization
Nonlinear Optimization
Higher Order
Derivatives
File
Euclidean norm
Higher Order
Local Minimizer
Vector-valued Functions
Taylor series
Yield spread
Asset prices
Surprise
Credit rating
Price dynamics

Worst-case evaluation complexity for unconstrained nonlinear optimization using high-order regularized models

Birgin, E., Gardenghi, J., Martinez, J-M., Santos, S. A. & Toint, P. Jun 2015 2015: Namur center for complex systems, 8 p.(naXys Technical Reports; vol. 05-2015)

Research output: Working paper

File
Unconstrained Optimization
Nonlinear Optimization
Higher Order
Derivatives
Derivative
2014
File
Interior Point
Nonlinear Optimization
Matrix Derivative
Merit Function
Quadratic Optimization
2013

Adaptive Observations And Multilevel Optimization In Data Assimilation

Gratton, S., Rincon-Camacho, M. & Toint, P. 2013 Namur: Namur center for complex systems, 18 p.

Research output: Working paper

File
data assimilation
decomposition
wave equation
weather
prediction
File
Unconstrained Minimization
Steepest Descent Method
Evaluation Function
Terminate
Iterate
2012
2011
File
Forced oscillation
Integrable Systems
Numerical Algorithms
Search Algorithm
Initial conditions
1981