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1.
This paper provides several constructions of compactly supported wavelets generated by interpolatory refinable functions. It was shown in [7] that there is no real compactly supported orthonormal symmetric dyadic refinable function, except the trivial case; and also shown in [10,18] that there is no compactly supported interpolatory orthonormal dyadic refinable function. Hence, for the dyadic dilation case, compactly supported wavelets generated by interpolatory refinable functions have to be biorthogonal wavelets. The key step to construct the biorthogonal wavelets is to construct a compactly supported dual function for a given interpolatory refinable function. We provide two explicit iterative constructions of such dual functions with desired regularity. When the dilation factors are larger than 3, we provide several examples of compactly supported interpolatory orthonormal symmetric refinable functions from a general method. This leads to several examples of orthogonal symmetric (anti‐symmetric) wavelets generated by interpolatory refinable functions. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

2.
变阶唯一可解函数的一致逼近   总被引:1,自引:0,他引:1  
祝长忠 《计算数学》1989,11(3):257-261
设F(A,x)是连续依赖于x∈[a,b]和参数A∈P的实值函数,其中P是实n维空间的一个非空子集,并设F(A,x)是Rice意义下的变阶唯一可解函数[1,p.3—6],它关于P具有最大阶n。这类函数最典型的是由Meinardus提出的一种具有局部  相似文献   

3.
GAUSS-SEIDEL-TYPE MULTIGRID METHODS   总被引:1,自引:0,他引:1  
By making use of the Gauss-Seidel-type solution method, the procedure for computing the interpolation operator of multigrid methods is simplified. This leads to a saving of computational time. Three new kinds of interpolation formulae are obtained by adopting different approximate methods, to try to enhance the accuracy of the interpolatory oper-ator. A theoretical study proves the two-level convergence of these Gauss-Seidel-type MG methods. A series of numerical experiments is presented to evaluate the relative perfor-mance of the methods with respect to the convergence factor, CPU-time(for one V-cycle and the setup phase) and computational complexity.  相似文献   

4.
时军  马锦锦 《大学数学》2007,23(5):152-155
在等距结点分布的情况下,对振荡积分分别导出由Ⅰ,Ⅱ,Ⅲ型三次样条构造的插值型求积公式,进行了误差估计,并举出数值实例说明该公式确实具有较高代数精确度.  相似文献   

5.
Haselgrove's method is currently considered to be the best for the numerical integration of smooth functions in very many (say, 6 or more) dimensions. This method, however, does not warrant the practically required accuracy of 3 significant decimals for integrands of remarkable variability. The method proposed in this paper introduces a skillful use of samplings to a multidimensional interpolatory quadrature scheme, and is shown to guarantee the above practical accuracy even where Haselgrove's method fails. This method has been devised especially for multivariable composite functions made up of complicated element functions of fewer variables.  相似文献   

6.
It is well known that the critical Hölder regularity of a subdivision schemes can typically be expressed in terms of the joint-spectral radius (JSR) of two operators restricted to a common finite-dimensional invariant subspace. In this article, we investigate interpolatory Hermite subdivision schemes in dimension one and specifically those with optimal accuracy orders. The latter include as special cases the well-known Lagrange interpolatory subdivision schemes by Deslauriers and Dubuc. We first show how to express the critical Hölder regularity of such a scheme in terms of the joint-spectral radius of a matrix pair {F0,F1} given in a very explicit form. While the so-called finiteness conjecture for JSR is known to be not true in general, we conjecture that for such matrix pairs arising from Hermite interpolatory schemes of optimal accuracy orders a “strong finiteness conjecture” holds: ρ(F0,F1)=ρ(F0)=ρ(F1). We prove that this conjecture is a consequence of another conjectured property of Hermite interpolatory schemes which, in turn, is connected to a kind of positivity property of matrix polynomials. We also prove these conjectures in certain new cases using both time and frequency domain arguments; our study here strongly suggests the existence of a notion of “positive definiteness” for non-Hermitian matrices.  相似文献   

7.
New explicit, zero dissipative, hybrid Numerov type methods are presented in this paper. We derive these methods using an alternative which avoids the use of costly high accuracy interpolatory nodes. We only need the Taylor expansion at some internal points then. The method is of sixth algebraic order at a cost of seven stages per step while their phase lag order is fourteen. The zero dissipation condition is satisfied, so the methods possess an non empty interval of periodicity. Numerical results over some well known problems in physics and mechanics indicate the superiority of the new method.  相似文献   

8.
This paper describes an algebraic construction of bivariate interpolatory subdivision masks induced by three-directional box spline subdivision schemes. Specifically, given a three-directional box spline, we address the problem of defining a corresponding interpolatory subdivision scheme by constructing an appropriate correction mask to convolve with the three-directional box spline mask. The proposed approach is based on the analysis of certain polynomial identities in two variables and leads to interesting new interpolatory bivariate subdivision schemes.  相似文献   

9.
Starting from a well-known construction of polynomial-based interpolatory 4-point schemes, in this paper we present an original affine combination of quadratic polynomial samples that leads to a non-uniform 4-point scheme with edge parameters. This blending-type formulation is then further generalized to provide a powerful subdivision algorithm that combines the fairing curve of a non-uniform refinement with the advantages of a shape-controlled interpolation method and an arbitrary point insertion rule. The result is a non-uniform interpolatory 4-point scheme that is unique in combining a number of distinctive properties. In fact it generates visually-pleasing limit curves where special features ranging from cusps and flat edges to point/edge tension effects may be included without creating undesired undulations. Moreover such a scheme is capable of inserting new points at any positions of existing intervals, so that the most convenient parameter values may be chosen as well as the intervals for insertion.Such a fully flexible curve scheme is a fundamental step towards the construction of high-quality interpolatory subdivision surfaces with features control.  相似文献   

10.
崔丽鸿  张新敬 《数学杂志》2005,25(3):259-264
对具有任意伸缩矩阵A的插值加细函数,给出对应于L^2(R^s)中的小波包的一个构造方法.采样空间被直接分解来取代对加细函数的符号分解.按照这个方法构造的插值小波包能对基插值空间提供较为精细的分解,因而对自适应的插值给出较好的局部化.  相似文献   

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