m — Manipulate data

Documentation

Reference

Commands

m — Manipulate data

Operations are organized by scope: point-level (within a spectrum), spectrum-level (reorders or merges spectra), and file-level (combines files in memory).

Protection

Command	Action
`m/ <spectra>`	Protect listed spectra from the next operation
`m/-`	Lift all protections

Use protection to exclude a reference spectrum (e.g. an empty-cell measurement) while operating on the rest:

0 > m/ 0          # protect spectrum 0
0 > oy y-y[,0]    # subtract spectrum 0 from all others
0 > m/-

Point-level operations

Command	Action
`md <expr>`	Delete points where expression is true
`mr <expr>`	Retain points where expression is true
`mpd`	Per-point delete (interactive)
`mpr`	Per-point retain (interactive)
`mpa <factor>`	Bin points by a (possibly non-integer) factor
`mpaf <n>`	Bin points by a fixed integer factor n
`mpaea`	Bin until absolute error bound is met
`mpaer`	Bin until relative error bound is met
`mpo`	Sort points by x
`mpq`	Average coincident x values
`mpsym`	Symmetrize: average y(x) and y(−x) onto a common x > 0 grid

mpa vs mpaf

mpa <factor> bins adjacent points by an arbitrary factor, but the resulting x grid may be non-equidistant, which prevents fast convolution during fitting.

Prefer mpaf <n> whenever you plan to fit with cf: it bins by an integer n, always produces an equidistant grid, and keeps fast convolution available.

0 > mpaf 5        # bin 5→1, grid stays equidistant
0 > cf            # fast convolution works

Spectrum-level operations

Command	Action
`msd <range>`	Delete spectra
`msr <range>`	Retain spectra
`msa <groups>`	Average spectra in groups
`msb`	Split file into one file per spectrum
`msj`	Join corresponding spectra from multiple files
`ms*`	Spawn: duplicate each spectrum n times, adding a copy-index z
`msx`	Exchange: swap the last z coordinate with x
`mso <expr>`	Sort spectra by expression
`msoz`	Sort spectra by z-value
`mzx`	Exchange or rotate z coordinates
`mz-`	Delete the last z coordinate

msx — exchange x and z

msx swaps the x axis with the last z coordinate. The old x values become the new z, and the old z values become the new x. Each unique z-value in the original file becomes a spectrum.

Typical use: a file has spectra measured at different scattering angles q (z0), with energy transfer E as x. After msx, q is x and the E grid values become z — turning a set of S(E) spectra into a set of S(q) spectra.

mzx — rotate z coordinates

mzx interactively swaps or rotates the order of the z coordinates when a file has two or more of them (z0, z1, …). Use it to reorder which coordinate is treated as the “primary” z.

ms* — spawn spectra

ms* asks for a number n and produces n copies of each spectrum, adding a new z0 coordinate (0, 1, … n−1) to distinguish them. Useful for building a reference structure before assigning different y values to each copy.

File-level operations

Command	Action
`mfj`	Merge files end-to-end (concatenate spectra)
`mfj+`	Merge files, adding z = source file index
`mfjp`	Merge files pointwise (concatenate data points per spectrum)
`mr-`	Remove a file constant

mfjp — pointwise merge

mfjp merges the selected files by concatenating the data points of corresponding spectra, not the spectra themselves. All input files must have the same number of spectra and compatible x/y coordinates. The result has the same number of spectra but more data points per spectrum.

Typical use: combining the same measurement taken in two different x ranges into a single spectrum with full coverage.

Other operations

Command	Action
`mi`	Inverse interpolation: given y = y₀, find x such that y(x) = y₀
`mhm`	Bin data into a histogram