National Repository of Grey Literature 131 records found  1 - 10nextend  jump to record: Search took 0.02 seconds. 
Some modifications of the limited-memory variable metric optimization methods
Vlček, Jan ; Lukšan, Ladislav
Several modifications of the limited-memory variable metric (or quasi-Newton) line search methods for large scale unconstrained optimization are investigated. First the block version of the symmetric rank-one (SR1) update formula is derived in a similar way as for the block BFGS update in Vlˇcek and Lukˇsan (Numerical Algorithms 2019). The block SR1 formula is then modified to obtain an update which can reduce the required number of arithmetic operations per iteration. Since it usually violates the corresponding secant conditions, this update is combined with the shifting investigated in Vlˇcek and Lukˇsan (J. Comput. Appl. Math. 2006). Moreover, a new efficient way how to realize the limited-memory shifted BFGS method is proposed. For a class of methods based on the generalized shifted economy BFGS update, global convergence is established. A numerical comparison with the standard L-BFGS and BNS methods is given.
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Protection of personality rights in China in view of the new Civil Code
Vlček, Jan ; Lomová, Olga (advisor) ; Hála, Martin (referee)
This bachelor thesis presents the regulation of personality rights in the first ever Civil Code of the PRC 中华人民共和国民法典. Prior to the promulgation of the Civil Code personality rights had been scattered across various legal norms. In this respect, the codification is a significant legal achievement. This thesis seeks to answer the question of whether the Civil Code offers a greater degree of protection than the previous regulation, and to what extent is this protection enforceable. Following a few introductory chapters, which put some key words in context, most of the thesis is devoted to a comparison of the old and new regulation. The thesis concludes that although the Code has succeeded in introducing several new institutes also familiar to the continental law doctrine, in a number of areas the Code has not remedied the deficiencies of the original regulation; in other places, it even introduces new controversial provisions, which in some cases are linked to specific power interests of the CCP. Powered by TCPDF (www.tcpdf.org)
Two limited-memory optimization methods with minimum violation of the previous quasi-Newton equations
Vlček, Jan ; Lukšan, Ladislav
Limited-memory variable metric methods based on the well-known BFGS update are widely used for large scale optimization. The block version of the BFGS update, derived by Schnabel (1983), Hu and Storey (1991) and Vlček and Lukšan (2019), satisfies the quasi-Newton equations with all used difference vectors and for quadratic objective functions gives the best improvement of convergence in some sense, but the corresponding direction vectors are not descent directions generally. To guarantee the descent property of direction vectors and simultaneously violate the quasi-Newton equations as little as possible in some sense, two methods based on the block BFGS update are proposed. They can be advantageously combined with methods based on vector corrections for conjugacy (Vlček and Lukšan, 2015). Global convergence of the proposed algorithm is established for convex and sufficiently smooth functions. Numerical experiments demonstrate the efficiency of the new methods.
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Hybrid Methods for Nonlinear Least Squares Problems
Lukšan, Ladislav ; Matonoha, Ctirad ; Vlček, Jan
This contribution contains a description and analysis of effective methods for minimization of the nonlinear least squares function F(x) = (1=2)fT (x)f(x), where x ∈ Rn and f ∈ Rm, together with extensive computational tests and comparisons of the introduced methods. All hybrid methods are described in detail and their global convergence is proved in a unified way. Some proofs concerning trust region methods, which are difficult to find in the literature, are also added. In particular, the report contains an analysis of a new simple hybrid method with Jacobian corrections (Section 8) and an investigation of the simple hybrid method for sparse least squares problems proposed previously in [33] (Section 14).
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Application of the Infinitely Many Times Repeated BNS Update and Conjugate Directions to Limited-Memory Optimization Methods
Vlček, Jan ; Lukšan, Ladislav
To improve the performance of the L-BFGS method for large scale unconstrained optimization, repeating of some BFGS updates was proposed. Since this can be time consuming, the extra updates need to be selected carefully. We show that groups of these updates can be repeated infinitely many times under some conditions, without a noticeable increase of the computational time. The limit update is a block BFGS update. It can be obtained by solving of some Lyapunov matrix equation whose order can be decreased by application of vector corrections for conjugacy. Global convergence of the proposed algorithm is established for convex and sufficiently smooth functions. Numerical results indicate the efficiency of the new method.
Mountain hotel
Vlček, Jan ; Pilný, Ondřej (referee) ; Berková, Petra (advisor)
The aim of this diploma thesis is to design a mountain hotel in the village Rokytnice nad Jizernou. The object is placed on a sloping plot located in an attractive touristic and skiing area of mountain range Krkonoše. The mountain hotel has 4 floors and a basement. In the First floor there is a restaurant with a terrace, kitchen and administrative facilities of hotel. In the second and third floor we can find guest rooms and room for the hotel staff. In the basement there is wellness, technical facilities and garage compound. Construction of building is made of the reinforced concrete monolithic transverse frames with beam filling of ceramic block.
A Hybrid Method for Nonlinear Least Squares that Uses Quasi-Newton Updates Applied to an Approximation of the Jacobian Matrix
Lukšan, Ladislav ; Vlček, Jan
In this contribution, we propose a new hybrid method for minimization of nonlinear least squares. This method is based on quasi-Newton updates, applied to an approximation A of the Jacobian matrix J, such that AT f = JT f. This property allows us to solve a linear least squares problem, minimizing ∥Ad+f∥ instead of solving the normal equation ATAd+JT f = 0, where d ∈ Rn is the required direction vector. Computational experiments confirm the efficiency of the new method.
Problems for Nonlinear Least Squares and Nonlinear Equations
Lukšan, Ladislav ; Matonoha, Ctirad ; Vlček, Jan
This report contains a description of subroutines which can be used for testing large-scale optimization codes. These subroutines can easily be obtained from the web page http://www.cs.cas.cz/~luksan/test.html. Furthermore, all test problems contained in these subroutines are presented in the analytic form.
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Sparse Test Problems for Nonlinear Least Squares
Lukšan, Ladislav ; Matonoha, Ctirad ; Vlček, Jan
This report contains a description of subroutines which can be used for testing large-scale optimization codes. These subroutines can easily be obtained from the web page http://www.cs.cas.cz/~luksan/test.html. Furthermore, all test problems contained in these subroutines are presented in the analytic form.
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National Repository of Grey Literature : 131 records found   1 - 10nextend  jump to record:
See also: similar author names
11 VLČEK, Jakub
12 VLČEK, Jiří
11 Vlček, Jakub
12 Vlček, Jiří
9 Vlček, Josef
2 Vlček, Jozef
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