scholarly journals On the Locally Polynomial Complexity of the Projection-Gradient Method for Solving Piecewise Quadratic Optimisation Problems

Entropy ◽  
2021 ◽  
Vol 23 (4) ◽  
pp. 465
Author(s):  
Agnieszka Prusińska ◽  
Krzysztof Szkatuła ◽  
Alexey Tret’yakov

This paper proposes a method for solving optimisation problems involving piecewise quadratic functions. The method provides a solution in a finite number of iterations, and the computational complexity of the proposed method is locally polynomial of the problem dimension, i.e., if the initial point belongs to the sufficiently small neighbourhood of the solution set. Proposed method could be applied for solving large systems of linear inequalities.

Author(s):  
Valentin A. Bereznev

AbstractAn approach based on projection of a vector onto a pointed convex polyhedral cone is proposed for solving the quadratic programming problem with a positive definite matrix of the quadratic form. It is proved that this method has polynomial complexity. A method is said to be of polynomial computational complexity if the solution to the problem can be obtained in N


Author(s):  
Natarajan Ramachandran ◽  
Noshir A. Langrana ◽  
Louis Steinberg

Abstract This paper discusses methods to retrieve design(s) from a design library in order to achieve a better initial starting point for the iterative model of the design process. The motivation for doing this is to reduce the extensive analysis time required for many iterative design problems. Starting a design at a favorable initial point should help reduce the number of iterations. Four initial design methods have been investigated varying from a simple non-library method to methods that use designs from a library. To evaluate the effectiveness of these methods, the initial design methods were tested on four example problems. They are, a cantilever beam, a gear-pair, a v-belt and an extruder-die. It was found that the number of iterations reduced approximately as 1/n, where n is the number of stored values in the design library.


2019 ◽  
Vol 42 (3) ◽  
pp. 503-517
Author(s):  
Masoud Hajarian

The study of linear matrix equations is extremely important in many scientific fields such as control systems and stability analysis. In this work, we aim to design the Hestenes-Stiefel (HS) version of biconjugate residual (Bi-CR) algorithm for computing the (least Frobenius norm) partially doubly symmetric solution [Formula: see text] of the general Sylvester matrix equations [Formula: see text] for [Formula: see text]. We show that the proposed algorithm converges in a finite number of iterations. Finally, numerical results compare the proposed algorithm to alternative algorithms.


2011 ◽  
Vol 486 ◽  
pp. 179-182 ◽  
Author(s):  
Adam Sędziwy ◽  
Leszek Kotulski

In the paper we focus on the problem of large-scale distribution of lighting points. Its solution is constrained by economic issues like power consumption or exploitation costs and, on the other side, by the computational complexity of design process. Multi-agent computational environment combined with graph and hypergraph representations of a problem allow meeting design requirements and objectives and, on the other hand, make the method applicable for large systems for which computational effectiveness is a crucial factor.


2005 ◽  
Vol 02 (01) ◽  
pp. 45-53 ◽  
Author(s):  
S. E. EL-KHAMY ◽  
M. M. HADHOUD ◽  
M. I. DESSOUKY ◽  
B. M. SALAM ◽  
F. E. ABD EL-SAMIE

This paper presents a least squares block by block adaptive approach for the acquisition of high resolution (HR) images from available (LR) images. The suggested algorithm is based on the segmentation of the image to overlapping blocks and the interpolation of each block separately. The purpose of the overlapping of blocks is to avoid edge effects. An adaptive 2D least squares approach, which considers the image acquisition model, is used in the minimization of the estimation error of each block. In this suggested algorithm, a weight matrix of moderate dimensions is estimated in a small number of iterations to interpolate each block. This algorithm avoids the large computational complexity due to the matrices of large dimensions required to interpolate the image as a whole. The performance of the proposed algorithm is studied for different LR images with different SNRs. The performance of the proposed algorithm is also compared to the standard as well as the warped distance cubic O-MOMS image interpolation algorithms from the PSNR point of view.


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