Working in Scripts

Long computations (high orders, many checks) are easier to run as scripts than in a notebook. A script is a file of Wolfram Language code, run.wl, run from a shell:

wolfram -script run.wl         # or: wolframscript -file run.wl

The two commands do the same; on some installations only one of them is available. A script prints only what you Print: results of statements are not shown, the banner of the package is not printed, and the package does not look for a newer release (Installation).

Printing results

In a script Print writes the input form, in which the integration variables are DummyVariable[1, 1], DummyVariable[1, 2], ...; ToString writes them as in a notebook, z1, z2, ...:

Needs["FunctionalDiagrams`"]
DeclareSymmetric[V];
fock = SimplifyDiagrams[IntegralOver[G[x, u] V[u, v] G[u, v] G[v, y], {u, v}]];
Print[ToString[fock]]

IntegralOver[G[x, z2] G[z1, y] G[z2, z1] V[z1, z2], {z1, z2}]

For a value that you want to read back later, write the input form to a file and Get it: Put[result, "result.m"], then result = Get["result.m"].

Lines and statements

A statement ends at the end of a line where it is complete:

total = OrderPart[green, V, 1]
  + OrderPart[green, V, 2]

is two statements, the second a lone + OrderPart[...]. Break long lines after an operator, or inside brackets:

total = OrderPart[green, V, 1] +
  OrderPart[green, V, 2]

Long computations

• Compute only the orders you need ({k} in PerturbativeCorrelationFunction, "CouplingOrder", "MaximumOrder": see Orders and simplification).
• AbsoluteTiming[expr] gives the time and the result; the showcase writes the times of its main steps in Showcase/figures/values.txt.
• Pictures can be written to files from a script: Export["green.pdf", DiagramPlot[green, {x, y}]] (the front end is started in the background for it), or DiagramToTikZ to a .tex file, see Pictures in LaTeX.

Examples in the repository

Examples.wl (the guided tour), Showcase/make_figures.wl (everything in the showcase) and Tests/RunTests.wl (the test suite) are scripts; each one loads the package from the repository with Get.