Statistics loves APL

ABSTRACT

To call this paper 'STATISTICIANS LOVE APL' would be self-deluding. To call it 'SOME STATISTICIANS LOVE APL' though vague would be accurate. However a balance then might be desirable by appending '… AND SOME STATISTICIANS HATE APL'. But that title would be both too long and almost vacuous. Nevertheless, this brief historical record at a personal level of the prominent place APL has played, first in the research, second in the teaching, and third in the consultative, activities of the Department of Statistics at the University of New South Wales since 1970 will help to explain and justify such titles. The affinity between Statistics and APL derives primarily from the correspondence between the mathematical structure of much statistical analysis and the structure of APL. Successful exploitation of this correspondence depends on how Statistics is learnt, taught and used. For example, at the teaching level an entirely theoretical course in Statistics which never does anything with numbers will only rarely make contact with computing. Similarly, a 'methods' or 'cookbook' course involving computing will depend on packages which if they use APL will typically do so invisibly. How the correspondence between mathematical structure and APL has been utilized at the University of New South Wales is sketched below. Whilst I was on leave in 1969 from the University of New South Wales at Penn State University doing some heavy statistical computing, the Computing Center called me to say that IBM had given Penn State access to an APL interpreter for a couple of months. I had not heard of APL, but was told it was a splendid system for array manipulation, and that I could have a demonstration, and then some time for personal playing. It was enormously impressive to see how easily arrays could be processed, but because I saw no likelihood that on returning to N.S.W. I would still have access to APL I did not follow up the offer to use it. But before my return to Australia IBM (Aust.) had established the Systems Development Institute in Canberra, and was providing contracts for use of its facilities - amongst these was APL\360; and the School of Mechanical Engineering of the University of N.S.W. (via G. de Vahl Davis) was carrying out a project using APL in engineering education through W.N. Holmes of IBM.

INDEX TERMS

Primary Classification:
  G. Mathematics of Computing
  G.3 PROBABILITY AND STATISTICS
      Subjects: Statistical computing

Additional Classification:
  C. Computer Systems Organization
  C.5 COMPUTER SYSTEM IMPLEMENTATION
      C.5.1 Large and Medium ("Mainframe") Computers

          Nouns: IBM System/360

  D. Software
  D.3 PROGRAMMING LANGUAGES
      D.3.2 Language Classifications

          Nouns: APL

  E. Data
  E.1 DATA STRUCTURES
      Subjects: Arrays

  G. Mathematics of Computing
  G.1 NUMERICAL ANALYSIS
      G.1.2 Approximation
          Subjects: Least squares approximation

  K. Computing Milieux
  K.2 HISTORY OF COMPUTING

      Nouns: APL

General Terms:
Algorithms, Design, Human Factors, Languages