关于几类矩阵方程的解法

<正> 本文给出矩阵方程AXB=C的快速解法和矩阵方程XDX+AX+XB+C=0的某些特殊情形的解法。 (一)关于矩阵方程AXB=C已有一般的解法,参考文献(1)本文只给出它的一个快速解法。定理1 设有矩阵方程AX=B(A非奇异) 则可用矩阵方程的初等行变换将(A:B)变到(I:X)即将A变到I(这里I为单位矩阵)时,同时也就将B变为X了。     

零和自由半环上的半可逆矩阵

在零和自由半环上,举例说明矩阵方程组AX=B和X+A_1B=A2B并不是在所有情况下都同解,其中A是已知的n×n阶半可逆矩阵,X是未知的n维列向量,A_1和A_2分别满足条件I+AA_1=AA_2和I+A_1A=A_2A.得到关于方程AX=B和X+A_1B=A_2B同解的一些条件,完善零和自由半环上半可逆矩阵的相关性质,扩展矩阵的应用范围.     

耦合矩阵方程AX+XB=C,DX+X~TE=F的递度迭代算法

通过应用递阶辨识原理和推广求解矩阵方程AX=b的递度迭代算法,本文给出了求解耦合矩阵方程AX+XB=C,DX+XTE=F的递度迭代算法。分析表明,只要矩阵方程有唯一解,则对任何初始值此算法给出的迭代解都快速收敛到其真实解。一个数值例子表明了此算法的有效性。     

矩阵方程求解中SVD方法的讨论

分析了利用矩阵A(A∈Crm×n),B(B∈Ctm×n)的奇异值分解来求解矩阵方程AX=C(X∈Cm×n)与AXB=C(X∈Cn×m),讨论了有解的充分必要条件,并在有解时给出了解的一般形式.对于一般的无特殊规律矩阵方程,利用其奇异值分解来求解将会十分的方便.     

(AX,XC)=(B,D)的广义双对称解与广义双反对称解

设A,B是n×n阶矩阵,设C,D是n×m阶矩阵,研究了矩阵方程(AX,XC)=(B,D)具有广义双对称解和广义双反对称解的充要条件,并给出了矩阵方程(AX,XC)=(B,D)通解的表达式.     

关于矩阵方程AX+YB=C反问题的极小 Frobenius范数对称解

在线性约束下矩阵束最佳逼近问题中,对给定的条件做一改变,解决了一个矩阵束最佳逼近问题.设A、B、C都是m×n阶矩阵,当A和B满足同时奇异值分解(SSVD)时,解决了一个关于X,Y的矩阵方程AX+YB=C的反问题即求X∈SRn×n,Y∈SRm×m,使得满足‖AX+YB-C‖F=min,得到了其Frobenius范数对称解.     

r-置换因子循环线性系统求解的快速算法

在置换因子循环矩阵的基础上给出了r-置换因子循环矩阵的概念,得到以这类矩阵为系数的线性方程组AX=b有解的判定条件和快速算法.当r-置换因子循环矩阵非奇异时, 该快速算法求出线性方程组的唯一解,即存在唯一的r-置换因子循环矩阵C∈PRCMn,使AX=b的唯一解是C第一列;当r-置换因子循环矩阵奇异时, 该快速算法求出线性方程组的特解与通解,即存在唯一的r-置换因子循环矩阵H∈PRCMn及C∈PRCMn,使得C的第一列X1是AX=b的一个特解,而且X=X1+(I-H)Z是AX=b的通解,这里Z是任意的n维列向量.     

子空间上对称矩阵反问题

设 R(S)为一给定 n× n阶实矩阵 S的列空间 ,给出了矩阵方程反问题 AX =B在 R(S)上的对称阵类中有解的充分必要条件及通解的表达式 ,讨论了解对于已知矩阵的最佳逼近问题 ,给出了数值算法步骤     

方阵有群逆的一些充要条件

设A∈C~(n×n)(C~(n×n)表示复数域C上n阶方阵的全体),则矩阵方程组AXA=A,XAX=X,AX=XA的解X,称为A的群逆,记作A~#,并称A为有群逆.本文目的是给出方阵A有群逆的19个等价命题,并指出群逆是逆矩阵概念的一个较恰当的推广。     

赛德尔迭代的一个新的高效算法

本文提出一个新的高效赛德尔迭代算法(ESI算法)求解大型对称正定稀疏线性方程组AX=b。A是n*n阶的对称正定稀疏系数矩阵。A可表达为A=D+U~T+U,其中D是对角矩阵,U是主对角元素为零的上三角矩阵。这个算法,只需上三角阵非零元及其同等数量的索引信息压缩存储。每行第一个非零元存入界限信息而其他非零元仅需存入对应列号。整个系数矩阵存储量为τ,τ是A的非零元个数。压缩与还原过程仅需O(n)次加法或减法运算。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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