Yorick (programming language) explained

Yorick
File Ext:	.i
Designer:	David H. Munro
Latest Release Version:	2.2.04
Operating System:	Unix-like systems including macOS, Microsoft Windows
License:	BSD

Yorick is an interpreted programming language designed for numerics, graph plotting, and steering large scientific simulation codes. It is quite fast due to array syntax, and extensible via C or Fortran routines. It was created in 1996 by David H. Munro of Lawrence Livermore National Laboratory.

Features

Indexing

Yorick is good at manipulating elements in N-dimensional arrays conveniently with its powerful syntax.

Several elements can be accessed all at once:

> x=[1,2,3,4,5,6];> x[1,2,3,4,5,6]> x(3:6)[3,4,5,6]> x(3:6:2)[3,5]> x(6:3:-2)[6,4]

Arbitrary elements

> x=1,2,3,[4,5,6]]> x1,2,3,[4,5,6]]> x([2,1],[1,2])2,1,[5,4]]> list=where(1 list[2,3,4,5,6]> y=x(list)> y[2,3,4,5,6]

Pseudo-index

Like "theading" in PDL and "broadcasting" in Numpy, Yorick has a mechanism to do this:

> x=[1,2,3]> x[1,2,3]> y=1,2,3,[4,5,6]]> y1,2,3,[4,5,6]]> y(-,)1,[2],[3]],4,[5],[6]]]> x(-,)1,[2],[3]]> x(-)1,2,3> x(-)/y1,1,1,[0,0,0]]> y=1.,2,3,[4,5,6]]> x(-)/y1,1,1,[0.25,0.4,0.5]]

Rubber index

".." is a rubber-index to represent zero or more dimensions of the array.

> x=1,2,3,[4,5,6]]> x1,2,3,[4,5,6]]> x(..,1)[1,2,3]> x(1,..)[1,4]> x(2,..,2)5

"*" is a kind of rubber-index to reshape a slice(sub-array) of array to a vector.

> x(*)[1,2,3,4,5,6]

Tensor multiplication

Tensor multiplication is done as follows in Yorick:

P(+,)*Q(+)

means

\sum ^{j = N} _{j =1} {P _{ijkl} Q _{mnj} }

> x=1,2,3,[4,5,6]]> x1,2,3,[4,5,6]]> y=7,8,[9,10],[11,12]]> x(+)*y(+,)39,54,69,[49,68,87],[59,82,105]]> x(+,)*y(+)58,139,[64,154]]

External links

• Linux Journal Review
• Yorick tutorial on JehTech