冯·诺依曼(John von Neumann)
数学奇才、计算机之父
回顾 20 世纪科学技术的辉煌发展时,不能不提及 20 世纪最杰出的数学家之一的冯 · 诺依曼.众所周知, 1946 年发明的电子计算机,大大促进了科学技术的进步,大大促进了社会生活的进步.鉴于冯 · 诺依曼在发明电子计算机中所起到关键性作用,他被西方人誉为 \ 计算机之父 \ .
约翰 · 冯 · 诺依曼 ( John von Neumann , 1903 - 1957 ),美藉匈牙利人, 1903 年 12 月 28 日生于匈牙利的布达佩斯,父亲是一个银行家,家境富裕,十分注意对孩子的教育.冯 · 诺依曼从小聪颖过人,兴趣广泛,读书过目不忘.据说他 6 岁时就能用古 希腊语同父亲闲谈,一生掌握了七种语言.最擅德语,可在他用德语思考种种设想时,又能以阅读的速度译成英语.他对读过的书籍和论文.能很快一句不差地将内容复述出来,而且若干年之后,仍可如此. 1911 年一 1921 年,冯 · 诺依曼在布达佩斯的卢瑟伦中学读书期间,就崭露头角而深受老师的器重.在 费克特 老师的个别指导下并合作发表了第一篇数学论文,此时冯 · 诺依曼还不到 18 岁. 1921 年一 1923 年在苏黎世大学学习.很快又在 1926 年以优异的成绩获得了布达佩斯大学数学博士学位,此时冯 · 诺依曼年仅 22 岁. 1927 年一 1929 年冯 · 诺依曼相继在柏林大学和汉堡大学担任数学讲师。
1930 年接受了普林斯顿大学客座教授的职位,西渡美国. 1931 年成为该校 终身 教授. 1933 年转到该校的高级研究所,成为最初六位教授之一,并在那里工作了一生.冯 · 诺依曼是普林斯顿大学、宾夕法尼亚大学、哈佛大学、伊斯坦堡大学、马里兰大 学、哥伦比亚大学和慕尼黑高等技术学院等校的 荣誉 博士.他是美国国家科学院、秘鲁国立自然科学院和意大利国立林且学院等院的院士 . 1954 年他任美国原子能委员会委员; 1951 年至 1953 年任美国数学会主席.
1954 年夏,冯 · 诺依曼被使现患有癌症, 1957 年 2 月 8 日 ,在华盛顿去世,终年 54 岁. 冯 · 诺依曼在数学的诸多领域都进行了开创性工作,并作出了重大贡献.在第二次世界大战前,他主
要从事算子理论、鼻子理论、集合论等方面的研究. 1923 年关于集合论中超限序数的论文,显示了冯 · 诺依曼处理集合论问题所特有的方式和风格.他把集会论加以公理化,他的公理化体系奠定了公理集合论的基础.他从公理出发,用代数方法导出了集合论中许多重要概念、基本运算、重要定理等.特别在 1925 年的一篇论文中,冯 · 诺依曼就指出了任何一种公理化系统中都存在着无法判定的命题.
1933 年,冯 · 诺依曼解决了希尔伯特第 5 问题,即证明了局部欧几里得紧群是李群. 1934 年他又把紧群理论与波尔的殆周期函数理论统一起来.他还对一般拓扑群的结构有深刻的认识,弄清了它的代数结构和拓扑结构与实数是一致的.他对其子代数进行了开创性工作,并莫定了它的理论基础,从而建立了算子代数这门新的数学分支.这个分支在当代的有关数学文献中均称为冯 · 诺依曼代数.这是有限维空间中矩阵代数的自然推广.冯 · 诺依曼还创立了博奕论这一现代数学的又一重要分支. 1944 年发表了奠基性的重要论文《博奕论与经济行为》.论文中包含博奕论的纯粹数学形式的阐述以及对于实际博奕应用的详细说明.文中还包含了诸如统计理论等教学思想.冯 · 诺依曼在格论、连续几何、理论物理、动力学、连续介质力学、气象计算、原子能和经济学等领域都作过重要的工作.
冯 · 诺依曼对人类的最大贡献是对计算机科学、计算机技术和数值分析的开拓性工作.
现在一般认为 ENIAC 机是世界第一台电子计算机,它是由美国科学家研制的,于 1946 年 2 月 14 日在费城开始运行.其实由汤米、费劳尔斯等英国科学家研制的 \ 科洛萨斯 \ 计算机比 ENIAC 机问世早两年多,于 1944 年 1 月 10 日在布莱奇利园区开始运
行. ENIAC 机证明电子真空技术可以大大地提高计算技术,不过, ENIAC 机本身存在两大缺点:( 1 )没有存储器;( 2 )它用布线接板进行控制,甚至要搭接见天,计算速度也就被这一工作抵消
了. ENIAC 机研制组的莫克利和埃克特显然是感到了这一点,他们也想尽快着手研制另一台计算机,以便改进.
冯 · 诺依曼由 ENIAC 机研制组的戈尔德斯廷中尉介绍参加 ENIAC 机研制小组后,便带领这批富有创新精神的年轻科技人员,向着更高的目标进军. 1945 年,他们在共同讨论的基础上,发表了一个全新的 \ 存储程序通用电子计算机方案 \--EDVAC ( Electronic Discrete Variable AutomaticCompUter 的缩写).在这过程中,冯 · 诺依曼显示出他雄厚的数理基础知识,充分发挥了他的顾问作用及探索问题和综合分析的能力.
EDVAC 方案明确奠定了新机器由五个部分组成,包括:运算器、逻辑控制装置、存储器、输入和输出设备,并描述了这五部分的职能和相互关系. EDVAC 机还有两个非常重大的改进,即:( 1 )采用了二进制,不但数据采用二进制,指令也采用二进制;( 2 建立了存储程序,指令和数据便可一起放在存储器里,并作同样处理.简化了计算机的结构,大大提高了计算机的速度.
1946 年 7 , 8 月间,冯 · 诺依曼和戈尔德斯廷、勃克斯在 EDVAC 方案的基础上,为普林斯顿大学高级研究所研制 IAS 计算机时,又提出了一个更加完善的设计报告《电子计算机逻辑设计初探》.以上两份既有理论又有具体设计的文件,首次在全世界掀起了一股 \ 计算机热 \ ,它们的综合设计思想,便是著名的 \ 冯 · 诺依曼机 \ ,其中心就是有存储程序原则 -- 指令和数据一起存储.这个概念被誉为 ‘ 计算机发展史上的一个里程碑 \ .它标志着电子计算机时代的真正开始,指导着以后的计算机设计.自然一切事物总是在发展着的,随着科学技术的进步,今天人们又认识到 \ 冯 · 诺依曼机 \ 的不足,它妨碍着计算机速度的进一步提高,而提出了 \ 非冯 · 诺依曼机 \ 的设想.
冯 · 诺依曼还积极参与了推广应用计算机的工作,对如何编制程序及搞数值计算都作出了杰出的贡献. 冯 · 诺依曼于 1937 年获美国数学会的波策奖; 1947 年获美国总统的功勋奖章、美国海军优秀公民服务奖; 1956 年获美国总统的自由奖章和爱因斯坦纪念奖以及费米奖.
冯 · 诺依曼逝世后,未完成的手稿于 1958 年以《计算机与人脑》为名出版.他的主要著作收集在六卷《冯 · 诺依曼全集》中, 1961 年出版 .
( 摘自名人网 www.mingren.biz )
James Hardy Wilkinson
( 09/27/1919 --10/05/1986) : 数值分析和数值计算的开拓者和奠基人,第五位图灵奖获得者
James Hardy Wilkinson作为数值分析和数值计算的开拓者和奠基人是当之无愧的 . J. H. wilkinson 1919 年 9 月 27 日 生于英国 Strood,16 岁进入英国的剑桥大学三一学院学习,受到 Hardy 和 Littlewood 等数学大师的深刻影响,成绩优异 . 1940 年由于战争的需要,他开始研究弹道的数学模型与数值计算。 1946 年他奉命到伦敦的国家物理试验室,参与欧洲盟军司令部的计算机研究项目,成为 Turing 的助手,协助设计 Pilot ACE 计算机。
为了检测 Pilot ACE 计算机的运算,他编写了一个程序来求多项式的根,其中一个例子就是现在 数值分析中著名的 20 阶的 James H. Wilkinson 多项式
( 1 )
使他惊讶的是,计算出的根甚至不接近于准确根。由于计算机是经过测试的,因此 Wilkinson 首先认为问题可能出在程序或硬件上,但一个星期的探索使他又回到了起点。唯一剩下的事情是考虑问题本身,他发现该多项式的根对于系数的变化相当敏感(后来称之为病态问题)。虽然计算出的根是不准确的,但仍然是一个多项式的根,而且这个多项式与原来的多项式( 1 )系数非常接近,这把困难引回问题本身,使得人们更客观地进行思考。 Wilkinson 的这种观点导致了“向后误差分析”方法。
由于在数值分析研究领域的杰出贡献,其工作加速了数字计算机 ( 在科学计算中 ) 的使用,而且 Wilkinson 在线性代数计算和向后误差分析 (backward error analysis) 方法的创造性工作奠定了数值分析和数值计算早期的理论基础。 1975 年 J. H. Wilkinson 获得图灵奖。
高斯 (Gauss Carl Friedrich) 德国数学家( 1777-1855 )
高斯 , 德国数学家、物理学家、天文学家。 1777 年4 月30 日 生於不伦瑞克, 1855 年2 月23 日 卒于格丁根。高斯是近代数学奠基者之一,在历史上影响之大, 可以和阿基米德、牛顿、欧拉并列,有「 数学王子 」之称。
他幼年时就 表现出超人的数学天才。 1795 年进入格丁根大学学习。第二年他就发现正十七边形的尺规作图法。并给出可用尺规作出的正多边形的条件,解决了欧几里得以来悬而未决的问题。 1798 年转入黑尔姆施泰特大学, 1799 年获博士学位。 1807 年以后一直在格丁根大学 任 教授。
高斯的数学研究几乎遍及所有领域,在数论、代数学、非欧几何、复变函数和微分几何等方面都做出了开创性的贡献。他还把数学应用于天文学、大地测量学和磁学的研究,发明了 最小二乘法原理 。高理的数论研究 总结 在《 算术研究 》( 1801 )中,这本书奠定了近代数论的基础,它不仅是数论方面的划时代之作,也是数学史上不可多得的经典着作之一。高斯对代数学的重要贡献是证明了代数基本定理,他的存在性证明开创了数学研究的新途径。 高斯在 1816 年左右就得到非欧几何的原理。他还深入研究复变函数,建立了一些基本概念发现了着名的柯西积分定理。他还发现椭圆函数的双周期性,但这些工作在他生前都没发表出来。 1828 年高斯出版了《关于曲面的一般研究》,全面系统地阐述了空间曲面的微分几何学,并提出内蕴曲面理论。高斯的曲面理论后来由黎曼发展。 高斯一生共发表 155 篇论文,他对待学问十分严谨,只是把他自己认为是十分成熟的作品发表出来。其著作还有《 地磁概念 》和《 论与距离平方成反比的引力和斥力的普遍定律 》( 1840 )等。
高斯最出名的故事就是他十岁时,小学老师出了一道算术难题:「 计算 1 + 2 + 3? + 100 =? 」。 这可难为初学算术的学生,但是高斯却在几秒后将答案解了出来,他利用算术级数(等差级数) 的对称性,然后就像求得一般算术级数和的过程一样,把数目一对对的凑在一起: 1 + 100 , 2 + 99 , 3 + 98 , ??49 + 52 , 50 + 51 而这样的组合有 50 组,所以答案很快的就可以求出是: 101×50 = 5050 。
Gene H. Golub(1932 – 2007) 美国科学院、工程院和艺术科学院院士
A century ago, matrices and the techniques for their manipulation — linear algebra — were a backwater of mathematics. Today,they are the foundation not just of the mathematical field of numerical analysis, but also of computational science and engineering, and have become indispensable for anyone who wants to get numerical results from a computer. The pre-eminent figure in matrix computations over the past 50 years, Gene Golub, died on 16 November.
Golub was born in Chicago on 29 February 1932, to Jewish parents from Latvia and the Ukraine . His childhood was not affluent, but he was a good student. After two years at a junior college, he transferred to the University of Illinois at Urbana-Champaign,achieving his doctorate there in 1959. At the time, Illinois, with the first of its ? ILLIAC ' supercomputers, was a great centre of computing, and Golub showed his affection for his Alma Mater by endowing a chair there 50 years later. Rumour has it that the funds for the gift came from Google stock acquired in exchange for some advice on linear algebra. Google ' s PageRank search technology starts from a matrix computation — an eigenvalue problem with dimensions in the billions. Hardly surprising, Golub would have said: everything is linear algebra.
He came to believe that in his twenties, as he realized that new methods of orthogonal matrix factorization introduced by Wallace Givens and Alston Householder offered the right mathematical recipe for solving all kinds of problems. In particular, Golub focused on the idea known as singular value decomposition, SVD, which
systematically isolates the dominant components of a linear process.
Together with William Kahan and Christian Reinsch, he invented the nowstandard SVD algorithms, and showed scientists, engineers and statisticians how these algorithms could be used in areas such as the least-squares method to find the best fit to a curve; in optimization problems and control theory; and for the determination of crucial matrix parameters such as their norms, ranks and condition numbers. In later years he drove a car with the licence plate ? PROF SVD ' . Golub found his way to Stanford University in 1962, eventually becoming the senior professor in its formidable computer science department. In 45 productive years there, he advanced matrix computations in areas as diverse as geodesy, data mining and quantum chromodynamics. The dimension of what was considered a ? big ' matrix grew from 100 to 1,000,000 in the same period, and Golub was among the first to develop the iterative algorithms that make problems involving such huge matrices tractable.
As the new methods came in, older ideas such as gaussian elimination (essentially,the way one is taught to solve a system of simultaneous equations in school, by eliminating the variables one by one) became a smaller part of a new and greater enterprise. Along with the new algorithms came a new world of software for solving mathematical problems, such as EISPACK,LAPACK and MATLAB. Golub ' s book Matrix Computations , co-authored with Charles Van Loan of Cornell University,became a bestseller and the definitive textbook of the field. Honours flowed in,including membership of the US National Academies.
As a servant of the wider scientific community, Golub did as much as anybody to make the Society for Industrial and Applied Mathematics (SIAM) the organization it is today. He served it in various capacities, among them as president (1985 – 87). He also founded and edited two of the society ' s journals, the SIAM Journal on Scientific and Statistical Computing and SIAM Journal on Matrix Analysis and Applications . It was his proposal that led to the quadrennial International Congresses on Industrial and Applied Mathematics. But this impressive list of achievements misses the truly
extraordinary aspect of this complex man: the scale of his devotion to people. Golub was a bachelor for most of his life, and his colleagues were his family. No family ever had a more loving, attentive or exasperating father. As he liked to say, ― Every numerical analyst has a second home at Stanford ‖ . Countless colleagues enjoyed a glass of wine at his home there, and hundreds of them stayed over for a night or even a month at his invitation. How did he remember all our birthdays and reading tastes and children ' s names?
Golub could not spend a day without other people. He would eat dinner with them, talk matrices with them, organize conferences with them, write papers and books with them, argue academic politics with them — an endless dance of interactions, plans and projects. Anywhere in the world, a numerical analyst knows who is meant by ? Gene ' . About 250 of them were his co-authors. They knew that it would fall to them to do most of the writing; but Golub saw the connections, knew the literature, and made the paper happen.
He seemed almost to have invented e-mail. As early as 1981, his office computer was set up to beep the moment a message arrived. His personal address list evolved into the worldwide database of numerical analysts, and his notes to friends became the Numerical Analysis Digest. This newsletter,one of the first e-bulletins, is now sent to some 8,000 recipients weekly. He could not sit still. As he left us in Oxford last September after an extended sabbatical visit, having spent much of the preceding months talking with the graduate
students in the common room — to which he had donated $1,000 for a biscuit fund — he mentioned that he had three trips to China planned for the upcoming year.
Gene Golub was restless and never entirely happy. He was a
demanding friend; behind his back, we all had Gene stories to tell. It was a huge back: Gene was big, dominating any room he was in, and grew more impressive and imposing with the years. Graduate students around the world admired and loved him, and he bought them all dinner when he got the chance. His unexpected death, in Stanford in between speaking at a conference in Hong Kong and flying to Zurich for his eleventh honorary degree, has left the world of numerical analysis orphaned and reverberating.