1.2. ANGEL Language

When we want to plot a graph, we already have a data including results by calculation or experiment. In the general cases, such results are complosed of a couple of data like (x,y), or 3D data array, or multi-values with error bars. We want to see such results immediately on graph. And if these results look like good, we want to make the graph fine for paper. ANGEL enables realizing the procedure of graph in an easy way. You put some commands into your data file, ANGEL interprets the commands and data and creates PS file.

The structures of the commands and data have to follow the Angel language. This is similar to TeX and LaTeX. What you need only is a text editor for handling ANGEL . You do not need to know how to use TeX and LaTeX, but these can help you using ANGEL , since ANGEL includes the same format for equation and tabular as in TeX and LaTeX. So initial barrier is a little bit high for people who have never used TeX and LaTeX, particularly for Mac users.

An advantage of ANGEL will appear in data processing of your calculations or experimental data. If you put some ANGEL commands into your output of the calculations or experimental data, you can check them immediately on graph without any additional procedure or any other software only through ANGEL .

♠ PostScript: 3

It is hard to make program to show graphs on PC screen or to print them on various printers, since we have to know how to control screens or printers depending on the type of OS and printers. However, if we use PostScript language, it is enough to write only a scenario for graph. Also, Fortran language is enough to write a scenario. Indeed, ANGEL program is written in Fortran. The scenario is played by an interpreter installed in PS printer. In your PC, you can use Ghostscript and GSview to play the scenario on the screen as a strolling player.

♣ The origin of “ANGEL”

The interface of ANGEL has been made for tracing the interface of SATAN which is a graphic package of main frame of GSI. For six years, I used the SATAN system, and I put SATAN commands into all of my output of simulation codes so as to see the results on PC screen. After I came back to Japan in 1990, I looked for a graphic package as good as SATAN. But I could not find it. Then I started to make ANGEL by myself.

Since SATAN was a very nice system, people appeared one after another, who took it back without permission. GSI announced that copy of SATAN is forbidden. Against it, a bad guy brought it to Texas and named it “YAHWEH” fearlessly. Since I am a scientist who has reverence for God, I made the program in Fortran by myself and named it “ANGEL “. Angel and Satan are brother each other.