最小二乘线性逼近的一个注

给定m维实空间中N个点P_i=(x_1~((i)),x_2~((i)),…,x_m~((i)),i=1(1)N.对于任何超平面 k_1x_1+k_2x_2+…+k_mx_m+k_0=0,P_i到它的垂直距离平方和     

向量有理插值的一个行列式公式

<正> 设由不同实数组成的实数序列为x_0,x_1,x_2,…,对应的有限向量序列为(?)_0,(?)_1,(?)_2,…,其中(?)_i=(?)(x_1)∈D~d定义若向量有理函数(?)_n(x)=(?)(x)/q(x),其中(?)(x)是d 维多项式值向量,q(x)是实多项式,满足:     

最小平方解的有界性问题

§1.引言 实l~2空间是由序列x=(x_0,x_1,…,x_n,…)组成的空间,其中x_i(i=0,1,…)是实数,x满足     

等距节点上(0,3)插值五次样条

§1.引言 设f(x)是定义在[0,1]上的连续函数,n是自然数。记h=1/n, f_v~((r))=f~((r))(vh),v=0,1,…,n;r=0,1,…,5, f_(v 1/2)~((r))=f~((r))((v 1/2)h),v=0,1,…,n-1;r=0,1,…,5, ω_r(j)=max |f~((r))(x_1)-f~((r))(x_2)|,r=0,1,…,6. |x_1-x_2|≤h 0≤x_1,x_2≤1又设s(x)是[0,1]上满足(i)s(x)∈C~3[0,1],(ii)在[vh,(v 1)h]上s(x)∈∏_5,v=0,1,…,n-1的五次样条.它们的全体记为?_(n5)~((3)) .     

二元向量分叉连分式插值的矩阵算法

1 引言 设R~2中的点集Ⅱ~(n,m)由下表给出 (x_0,y_0)(x_0,y_1)…(x_0,y_m) (x_1,y_0)(x_1,y_1)…(x_1,y_m) (1.1) (x_n,y_0)(x_n,y_1)… (x_n,y_m)称Ⅱ~(n,m)为矩形网格.对Ⅱ~(n,m)中的每个点(x_i,y_i)给定d维插值向量v_(ij)并将其按上述方式排成向量网格且用中V~(n,m)记之. d维复向量V的Samelson逆定义为     

关于非等距的五次样条函数的缺插值

一f(x)是区间[0,1]上定义的函数,0=x_0相似文献   

F-相对极值超曲面的Bernstein性质(英文)

设x:M→R~(n+1)是一个局部严格凸的超曲面,由定义在一个凸域Ω()R~n上的严格凸函数x_(n+1)=f(x_1,x_2,…,x_n)给出.设Y=(0,0,…,0,1)是超曲面的古典相对法,则相应的余法场U=(-(()f)/(()x_1),-(()f)/(()x_2),…,-(()f)/(()x_n),1).本文相对于余法向量场U~F=F(ρ)U又定义了一个相对法化,称之为M的F-相对法化,其中ρ=[det(f_(ij))]~(-1/(n+2)),并证明了F-相对极值超曲面的Bernstein性质.     

用Householder变换约化对称带形矩阵为三对角形

对于对称带形矩阵,在[1]中用Givens变换将它约化为三对角形.现在我们用House-holder镜象变换进行约化.给出向量x=(x_1,…,x_(r-1),x_r,x_(r+1),…x_j,x_(j+1),…,x_n)~T,其中x_r,…,x_j不全为零,可以找到一个镜象变换H=I-uu~T/(2k~2),(1)其中向量u的分量u_i=0(i=1,2,…,r-1,j+1,…,n),u_r=x_r+s,u_i=x_i(i=r+1,…,j),s=±(sum from i=r to j x_i~2)~(1/2),2k~2=s~2+x_r s,s的正负号选取与x_r一致,使得Hx=(x…,x_(r-1),-S,0,     

相依误差下回归函数导数估计的强收敛速度

设Y_1,…,Y_n是在固定点x_1,…,x_n的n个观察值,适合模型 Y_i=g(x_i) ε_i,1≤i≤n.(1)这里g(·)是R上的未知函数,{ε_i}为随机(误差)变量序列,且假定0=x_0≤x_1≤…≤x_(n-1)≤x_n=1. 给定非负整数p,为了估计g的p阶导数g~(p)(x)(p=0时,即为g(x)),秦永松用     

关于非线性規划中鞍点定理的两点注記

§1.鞍点定理中的约束规格我们下面将沿用Arrow,Hurwicz,Uzawa在[2]中所用的术语和记号.准鞍点条件:如(?)使f(x)在约束g(x)≥0下取最大值,f(x)和g(x)是可微的,则存在(?)≥0使得(?)+(?)=0,(?)((?))=0.其中x是n维列向量〈x_1i,x_2,…,x_n〉,y是m维行向量(y_1,y_2,…,y_m).f(x)是     

关于广义逆的向量连分式插值样条

本文首次引入了关于广义逆的向量有理插值样条的概念．这类插值样条具有Thiele型连分式的截断分式的表现形式．在它的构造过程中,不必用到连分式的三项递推关系,本文得到的新的有效的系数算法具有递推运算的特点．存在性的一个充分条件得以建立．包括唯一性在内的有关插值问题的某些结果得到证明．最后,本文给出了一个精确的插值误差公式．     

Kernel Logistic Regression and the Import Vector Machine

The support vector machine (SVM) is known for its good performance in two-class classification, but its extension to multiclass classification is still an ongoing research issue. In this article, we propose a new approach for classification, called the import vector machine (IVM), which is built on kernel logistic regression (KLR). We show that the IVM not only performs as well as the SVM in two-class classification, but also can naturally be generalized to the multiclass case. Furthermore, the IVM provides an estimate of the underlying probability. Similar to the support points of the SVM, the IVM model uses only a fraction of the training data to index kernel basis functions, typically a much smaller fraction than the SVM. This gives the IVM a potential computational advantage over the SVM.     

A multidimensional continued fraction based on a high-order recurrence relation

The paper describes and studies an iterative algorithm for finding small values of a set of linear forms over vectors of integers. The algorithm uses a linear recurrence relation to generate a vector sequence, the basic idea being to choose the integral coefficients in the recurrence relation in such a way that the linear forms take small values, subject to the requirement that the integers should not become too large. The problem of choosing good coefficients for the recurrence relation is thus related to the problem of finding a good approximation of a given vector by a vector in a certain one-parameter family of lattices; the novel feature of our approach is that practical formulae for the coefficients are obtained by considering the limit as the parameter tends to zero. The paper discusses two rounding procedures to solve the underlying inhomogeneous Diophantine approximation problem: the first, which we call ``naive rounding' leads to a multidimensional continued fraction algorithm with suboptimal asymptotic convergence properties; in particular, when it is applied to the familiar problem of simultaneous rational approximation, the algorithm reduces to the classical Jacobi-Perron algorithm. The second rounding procedure is Babai's nearest-plane procedure. We compare the two rounding procedures numerically; our experiments suggest that the multidimensional continued fraction corresponding to nearest-plane rounding converges at an optimal asymptotic rate.

     

On a vector q‐d algorithm

Using the framework provided by Clifford algebras, we consider a non‐commutative quotient‐difference algorithm for obtaining the elements of a continued fraction corresponding to a given vector‐valued power series. We demonstrate that these elements are ratios of vectors, which may be calculated with the aid of a cross rule using only vector operations. For vector‐valued meromorphic functions we derive the asymptotic behaviour of these vectors, and hence of the continued fraction elements themselves. The behaviour of these elements is similar to that in the scalar case, while the vectors are linked with the residues of the given function. In the particular case of vector power series arising from matrix iteration the new algorithm amounts to a generalisation of the power method to sub‐dominant eigenvalues, and their eigenvectors. This revised version was published online in June 2006 with corrections to the Cover Date.     

Vector-valued Rational Interpolants II

Formulae for rational interpolation of vector data (in a spaceC^[d]) at distinct points are given. Its confluent case of vector-valuedPadé approximation is shown to be equivalent to the Germanpolynomial approximation problem. Formulae are given for thevector of numerator polynomials and for the denominator polynomial.A continued fraction interpolant for vector data is also given.The methods are characterized by their requirement that certaindistinguished directions in the space C^[d] form part of thespecification. The case of matrix Padé approximants forthe partial realization problem is explicitly discussed.     

A note on Thielen-fractions

In this paper we construct ann-fraction which is a generalization of a Thiele continued fraction. We prove that, under certain conditions, themth approximant of thisn-fraction solves the vector case of the rational interpolation problem.     

MATRIX ALGORITHMS AND ERROR FORMULA FOR BIVARIATE THIELE-TYPE RECTANGULAR MATRIX VALUED RATIONAL INTERPOLATION

A new method for the construction of bivariate matrix valued rational interpolants (BGIRI) on a rectangular grid is presented in [6]. The rational interpolants are of Thiele-type continued fraction form with scalar denominator. The generalized inverse introduced by [3]is gen-eralized to rectangular matrix case in this paper. An exact error formula for interpolation is ob-tained, which is an extension in matrix form of bivariate scalar and vector valued rational interpola-tion discussed by Siemaszko[l2] and by Gu Chuangqing [7] respectively. By defining row and col-umn-transformation in the sense of the partial inverted differences for matrices, two type matrix algorithms are established to construct corresponding two different BGIRI, which hold for the vec-tor case and the scalar case.     

The Genetic Sums' Representation for the Moments of a System of Stieltjes Functions and its Application

This paper deals with the spectral problems for high-order nonsymmetric difference operators. The method of investigation is based on the analysis of the genetic sums formulas for the moments of the operator. The parameters of these sums are shown to be connected with coefficients of the introduced vector Stieltjes continued fraction. The connections with vector orthogonality, Hermite—Padé approximation, and Hankel determinants are investigated. This gives a tool for the analysis of the solution of the direct and inverse spectral problem of the operator. It is applied to the integration of hierarchy of the discrete KdV equations. The existence of a global solution is proved. July 13, 1998. Date revised: July 12, 1999. Date accepted: July 26, 1999.     

预给极点的向量有理插值及性质

1　引　　言在工程技术中经常会遇到一些多元奇异函数的计算问题,常规的有理插值方法无疑为这类问题的近似求解提供了有效的途径,但有时逼近效果不一定十分理想,其重要原因之一是人们往往采用统一的框架去构造有理插值公式,而忽略了被逼近对象的一些本质特征.针对某些具体问题,例如已知被逼近的向量值函数的奇异点的有关信息,构造一种预给极点的向量有理插值格式就显得很有必要,其逼近效果自然会更理想.设R2中的点集Πn,m={(xi,yj)|i=0,1,…,n;j=0,1,…,m},相应的d维向量集Vn,m={Vi,j∈Cd|i=0,1,…,n;j=0,1,…,m}.设V∈Cd为任一d维…     

Matrix Continued Fraction for the Resolvent Function of the Band Operator

The aim of this paper is the expansion of a matrix function in terms of a matrix-continued fraction as defined by Sorokin and Van Iseghem. The function under study is the Weyl function or resolvent function of an operator, given in the standard basis by a bi-infinite band matrix, with p subdiagonals and q superdiagonals, where the p + q – 1 intermediate diagonals are zero. The main goal of this paper is to find, for the moments, an explicit form in terms of the coefficients of the continued fraction, called genetic sums, which lead to a generalization of the notion of a Stieltjes continued fraction. These results are extension of some results already found for the vector case (p = 1) and are a step in the direction towards the solution of the direct and inverse spectral problem. The actual computation of the approximants of the given function as the convergents of the continued fraction is shown to be effective. Some possible extensions are considered.