Syntax

EstraPy reads instructions from an input file, which defines the operations to perform on synchrotron data. These operations include loading experimental data, applying transformations, generating plots, and exporting results.

Commands are executed sequentially in the order they appear in the file, and many support multiple options for customization.

How Commands Work

Each command follows a simple, shell-like syntax:

command-name [arguments] [options] [subcommands]

Commands can span multiple lines for readability - continuation lines must start with at least one space.

For example:

preedge -150eV -25eV --linear

edge set Cu.K

Data Structure

EstraPy organizes data into pages and domains:

  • Pages - Represent individual data files or averaged results
  • Domains - Different data spaces (reciprocal, fourier, discriminant analysis)
  • Columns - Individual data arrays within a domain

Column Versioning

When a command modifies a column, EstraPy automatically preserves the original by creating a numbered backup:

E_0  →  (after modification)  →  E_0, E_1
a_0  →  (after modification)  →  a_0, a_1

You don’t need to worry about version numbers - commands automatically use the latest version when you reference a column by its base name (e.g., E always refers to the most recent E_N).

This ensures that most commands do not lose data during processing. Some commands, like cut, average, rebin and interpolate need to modify the length of the data and the original data is lost.

Domains

EstraPy currently supports two domains:

Domain Description Axes
reciprocal Original signal space Energy (E, eV), wavevector (k, Å⁻¹), absorption (mu), fine structure (chi), …
fourier Distance space after Fourier transform Distance (R, Å), Fourier transform magnitude (f), …

Most commands operate in the reciprocal domain by default. Commands like fourier explicitly transform data between the reciprocal and fourier domains.

Column Types

Each column is classified as either:

  • Axis - Independent variable (e.g., E, k, R)
  • Data - Dependent variable (e.g., mu, chi, f)
  • Noise - Uncertainty or noise estimates (starting with s, e.g., schi)

Some commands require you to specify which domain, axis, and columns to use. Others (like preedge) have sensible defaults and work with the only logical choices (reciprocal domain, E axis, a column).

Getting Started

For practical examples, see the Tutorials section.

Next: General Syntax - Learn the input file structure and syntax rules

Table of contents