Projects and files

Projects
New Project
Open Project
Open Recent
Save Project
Save Project As
What a project file holds
The .fitproj file format
Where the data came from
Unsaved changes
Import Profile
Two-column data files (.dat)
Price data files (.csv)
Reload Profile
Export Curve Parameters
Export Summary Table
Quit
Sample data
Command-line options
Log files
What Fit remembers between sessions

Projects

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

A project is your whole piece of work in one file, so that you can close Fit and later carry on fitting from where you stopped.

A project holds the data, everything you marked on it, the model, the values the last fit found and how the window was set up. Opening it again does not merely redraw what you had: the fitted values stay attached to the curves they belong to, so the next fit continues from them.

Project files end in .fitproj. The File menu holds the commands for them:

File > New Project (Ctrl+N) starts empty.
File > Open Project (Ctrl+O) opens a saved project, and File > Open Recent offers the last few again.
File > Save Project (Ctrl+S) and File > Save Project As (Ctrl+Shift+S) write the project.
File > Import Profile (F2) and File > Reload Profile bring data from a file into the project.
File > Export > Curve Parameters and File > Export > Summary Table write a table of results as text.

Saving and exporting are different things. A saved project can be opened again and is how you keep your work. An export is a one-way copy of a table for a spreadsheet or a script: Fit cannot open it again, and exporting does not count as saving.

The project open when you last closed Fit opens by itself at the next start.

Limitations

On macOS the shortcuts use the Command key instead of Ctrl.

New Project

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

File > New Project closes what is open and leaves an empty window, ready for a profile to be imported.

The profile, the background points, the fit intervals, the curve positions and the model are all removed from the window, and the title bar shows the program's name again. The new project has no file yet: the first File > Save Project asks for a name.

It also means no project will open by itself at the next start, until you open or save one.

The shortcut is Ctrl+N. The command is always offered.

With unsaved work in the window, it first asks whether to save the project, as closing the window does: Yes saves and then clears, No clears without saving, and Cancel - or a save that does not happen - leaves everything as it was.

See also: Save Project · Import Profile

Open Project

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

File > Open Project asks for a .fitproj file and restores the work it holds.

The dialog shows project files (*.fitproj), and can be switched to all files for a project that was renamed. Opening restores the profile, the background points, the fit intervals, the curve positions, the settings and the fitted values, and then the working context: the argument axis, the picking mode, the table in front and the selected curve. The title bar shows the project's file name.

The R-factor is not recalculated on opening. Until you fit again it reads as not calculated; the value the project recorded stays in the file.

If the file cannot be used, a message says why and the work already in the window is left as it was. Typical reasons: there is no file at that path, the file is not a Fit project, or it needs a newer version of Fit - the message then names the format version it needs and the one this build reads.

If the project names a curve type this build does not have, for example one from an analysis pack you do not have, the project still opens, with the curve type already selected here.

The shortcut is Ctrl+O. The command is always offered. A project can also be opened from the command line with /PROJECT, and on Windows by double-clicking a .fitproj file when the installer was allowed to associate the extension with Fit.

With unsaved work in the window, it first asks whether to save it, before the file dialog opens - the same question and the same answers as File > New Project. File > Open Recent asks it too.

Open Recent

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

File > Open Recent lists the projects you opened or saved most recently, newest first, and opens one with a click.

Each line is the whole path of a project, because two projects in different folders often have the same name. At most eight are kept. Opening or saving a project already in the list moves it to the top instead of listing it twice; two spellings of one path that differ only in capital letters count as the same project.

With no project remembered, the submenu shows one greyed line, (none), so that you can see the list is empty rather than missing.

The project at the top - the one open when Fit was last closed - opens by itself at the next start. If it has been moved or deleted in the meantime, Fit starts with nothing open, writes a warning to the log, and drops that project from the list.

The list is kept in Fit's settings file and written when the window closes.

Limitations

A project deleted while Fit is running stays in the list until the next start; clicking it reports that there is no project at that path.

Save Project

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

File > Save Project writes the project to its file, and asks for a name the first time.

A project that has never been saved has no file yet, so the first save behaves exactly like File > Save Project As. After that, File > Save Project writes to the same file without asking.

When the save succeeds, the title bar shows the project's file name, the project becomes the one that opens at the next start, and it moves to the top of File > Open Recent. If it fails - no such folder, no permission, a full disk - a message says why, the project still counts as unsaved, and the file already there is left exactly as it was: the new file is written beside it and takes its name only once it is complete.

The shortcut is Ctrl+S. The command is greyed out until a profile has been imported or a project opened: there is nothing to save before that.

Save Project As

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

File > Save Project As always asks for a file name and saves the project there.

Use it to keep a copy under another name, for example before trying a different model. From then on the window works on the new file: File > Save Project writes there.

If you type a name with no extension, .fitproj is added. A name you give with your own extension is kept as you typed it.

If a file of that name already exists, Fit asks whether to replace it, naming the file. The question is asked after the extension has been added, so it is about the file that would really be written. Answering No writes nothing and changes nothing.

The shortcut is Ctrl+Shift+S. The command is greyed out until a profile has been imported or a project opened.

What a project file holds

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

A project holds the data and everything needed to continue fitting it, but nothing that can be recalculated from those.

Stored in the file:

The profile as the program holds it at the time of saving, that is, after any background subtraction or smoothing.
Your background points, fit intervals and curve positions, and which curve each position belongs to.
The settings of the fit: the curve type, the wavelength, the maximum acceptable difference, the background fraction, the minimizer, the loss function, the weighting, and whether background variation and curve scaling are on.
For every curve, its fitted parameter values with their errors, and whether a fit produced them.
The R-factor and the statistics of the fit that was saved.
The formula and parameters of a user-defined curve, if one is in use.
The stretch of the profile you selected, if any, and where the data came from.
The working context: the argument axis (including a custom axis you defined), the picking mode, the table in front and the selected curve.
What any analysis module keeps about the model, in a part of its own.
When the project was created and last saved, in UTC, and which version of Fit wrote it.

Not stored: the calculated profile, the difference, the curves' own points and where the fitted curves sit. They are recalculated from what is stored, so a project cannot disagree with its own model. Also not stored: the window's size and position, and the settings that belong to your installation rather than to the work, such as the compute server's address or Animation Mode.

The original data file is not needed to open a project: the profile is inside it. The file's path is recorded, but only so that you can tell where the data came from.

Limitations

A parameter that is not a number - a label or a handle some curve types keep - is not stored. It is rebuilt from what the module keeps when the model is rebuilt.

The .fitproj file format

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

A .fitproj file is a ZIP archive of JSON parts, which any archive tool can open.

It is the same arrangement that .xlsx and OpenDocument files use. If something goes wrong you can unpack a project and read what it holds. The parts are:

manifest.json - which version of the format and of Fit wrote the file, the oldest format version a reader must understand to open it, and when it was created and saved.
problem.json - the profile, the background points, the fit intervals, the curve positions, the settings, the selected stretch, a user-defined curve and where the data came from.
results.json - the fitted values of every curve, the R-factor and the fit statistics.
ui.json - the working context of the window.
modules/<module>.json - one part for each analysis module that keeps something.

Old and new versions of Fit get along. When an older version opens a project written by a newer one and saves it, the parts and the entries it does not understand are written back unchanged, so passing a file between versions does not quietly lose work. A project that truly needs a newer reader is refused with a message saying so, rather than opened half understood.

Numbers are written at full precision, so a value comes back exactly as it was saved.

Limitations

Editing the parts by hand is possible but unchecked: a value that does not make sense may be refused, or taken as it is, when the project is opened.

Sources

PKWARE Inc., APPNOTE.TXT - .ZIP File Format Specification https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT
T. Bray (ed.), The JavaScript Object Notation (JSON) Data Interchange Format, RFC 8259 https://www.rfc-editor.org/rfc/rfc8259

Where the data came from

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

A project remembers which data file it was imported from, and notes in the log when that file no longer says the same thing.

When a profile is imported, Fit records the file's path, its size, a fingerprint of its contents (an MD5 hash) and the kind of file it was. All of it is saved with the project.

When the project is opened again, Fit reads the file at that path, if it is still there, and compares its contents with the fingerprint. If they differ, a warning goes to the log naming the file. Nothing in the project changes: it still holds the data it was fitted to. The notice is there so that a result which no longer matches its input can be noticed rather than puzzled over months later.

The contents are compared rather than the file's date, because copying or restoring a file changes its date without changing the data, and an edit can leave the date as it was.

Limitations

When the file is gone, cannot be read, or the project was saved by a version that recorded no fingerprint, nothing is said: Fit cannot tell, and does not guess that the data changed.
The fingerprint guards against accidents - a re-export, an edited column, a truncated copy - not against someone deliberately forging a file.

Unsaved changes

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

Closing Fit, starting a new project or opening another with unsaved work asks whether to save the project first, and a save that does not happen stops the command.

Whether you close the window, use File > Quit, or replace the project with File > New Project, File > Open Project or File > Open Recent, Fit asks "Project has been modified. Save?" when there is unsaved work, and does not ask when there is none.

Yes saves, exactly as File > Save Project does - asking for a name if the project has none - and then closes. If you cancel that name dialog, or the save fails, the window stays open, because closing then would lose the work you asked to keep.
No closes without saving.
Cancel, or closing the question, keeps the window open.

Work counts as unsaved when anything a save would write has changed since the project was last opened, saved or started from an imported file: the points picked for the background, the fit intervals or the curve positions, the model, a fit result, a setting. Changing the axis, the table in front or the selected curve does not count, and neither does exporting a table.

File > Import Profile and File > Reload Profile ask a question of their own, about the model they discard.

Import Profile

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

File > Import Profile reads a data file and makes it the profile of the current project.

The dialog, Open Profile Data, starts in the folder Fit is installed in. It offers the formats this build can read: All supported, then one entry per format, then All files. The file's extension decides how it is read, whatever its capitals:

.dat - a two-column text file, argument and value (Diffraction profile in the dialog).
.csv - price data with date, open, high, low and close columns (Price data, OHLC in the dialog).

A file with any other extension is refused with a message naming the extension no reader handles. An analysis module can add formats of its own; the dialog then lists them too.

Importing starts the model again: the curves, the picks and the fitted parameters describe the data being replaced. So when the project has curves or unsaved work, Fit first asks, naming the file, whether to replace the data and discard the current model. With nothing to lose it does not ask.

Afterwards the profile is on the chart and in the Data tab, and the title bar shows the data file's name. The project keeps its own file: File > Save Project saves the new data into it. The data file's path, size and fingerprint are recorded for the project.

The shortcut is F2, and the first toolbar button does the same. The command is always offered.

Limitations

There is no choice of columns in the dialog: a .dat file is always read as its first two numbers per line, and a .csv file as described under price data files.

Two-column data files (.dat)

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

A .dat file is plain text with the argument and the measured value on each line, and Fit reads the first two numbers of every line.

Each line should hold two numbers: first the argument (for a diffraction pattern, the angle), then the value (the intensity). Anything that is not part of a number separates numbers, so spaces, tabs and semicolons all work. For example:

116.0000 773.00

A number may have a sign (-1.5, +2) and an exponent (1.5e3, 2E-2). Its decimal mark may be a full stop or a comma. A comma is read as a decimal mark only on a line that writes no full stop, and only while that still leaves two numbers: 1,5;2,5 is one and a half and two and a half, while 12,40 and 12.5,40.0 are both pairs.

What the reader does without saying so:

A line with fewer than two numbers - a heading, a comment, a blank line - is skipped, as is a line holding a malformed number such as 1.2.3.
Everything after the second number on a line is ignored, so a third column (an error, say) is dropped.
A line whose argument is already in the file is skipped; the first one wins.
A minus sign written straight after a digit separates two numbers: 10-20 is the pair 10 and 20.

Limitations

A comment line that happens to contain two numbers (# run 3 of 5) is read as a data point. Start such lines with no numbers, or remove them, and compare the Data tab with the file.

Price data files (.csv)

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

A .csv file is read as a price series: one row per period, and the closing price becomes the value.

The separator - comma, semicolon or tab - is worked out from the first non-empty line. A semicolon wins a tie with commas, because files separated by semicolons usually write decimals with a comma.

A header row is recognised by its column names, in any capitals: Date (or Time, Timestamp, Datetime, observation_date), Open, High, Low and Close. An Adj Close column is preferred to Close when both are there. A header of exactly two columns, a date column first and one other, takes the other column as the value. A file with no recognisable header must have at least five columns, taken as date, open, high, low, close.

The value of each point is the closing price, and the argument is the row number, counting from 0, so that weekends and holidays leave no gaps - unless Data > Price Data chooses another column or the date as the argument.

A row that has no usable value - a blank, a missing observation written as a single full stop, a short last row - is skipped, and the log says how many were. A file with no usable row at all is refused.

Limitations

Only this price layout is read. A general comma-separated table of measurements is not; save it as a two-column .dat file instead.

Reload Profile

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

File > Reload Profile reads the data file the open project came from again, for when it has changed on disk.

It re-reads the file the project records as its source - the one imported last, or for a project opened from disk the one it was built from - in the same way it was read the first time, and replaces the profile with what it finds.

Like importing, it starts the model again, so when the project has curves or unsaved work Fit first asks whether to go on.

When the project names no data file, or the file is no longer where it was, Fit says so and reads nothing; use File > Import Profile to choose the file.

The command is greyed out until a profile has been imported or a project opened. It has no shortcut.

Export Curve Parameters

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

File > Export > Curve Parameters writes the Curve Attributes table to a tab-separated text file.

What is written is the table's content, headings included: one line per curve, the cells separated by tabs, with no tab after the last cell. A spreadsheet or a script reads it directly. It does not matter which table is in front when you use the command.

The numbers are written with every digit, not as the table rounds them, and with a full stop as the decimal mark whatever the computer's language settings. Where the fit estimated an uncertainty, it gets a column of its own beside its value, headed with the parameter's name and "error".

The dialog, Select File to Save Data, offers text files. A name typed with no extension gets .txt; one typed with an extension keeps it. If the file exists, Fit asks whether to overwrite it: Yes overwrites, No lets you choose another name, and Cancel writes nothing. An empty name asks whether to choose again.

The command is greyed out while the Curve Attributes table is empty.

Limitations

Fit cannot open an exported file again, and exporting does not count as saving the project.

See also: Export Summary Table · Save Project

Export Summary Table

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

File > Export > Summary Table writes the Summary table - data, model and difference point by point - to a tab-separated text file.

The Summary table has, for every point inside every fit interval, the argument, the measured value, the model's value, the difference and each curve's contribution, with a heading row for each interval. A curve that covers only part of an interval leaves the rest of its column blank.

The file is written exactly as for File > Export > Curve Parameters: headings included, every digit of each number, a full stop as the decimal mark, cells separated by tabs, .txt added to a name with no extension, and the same questions about an existing file or an empty name.

The command is greyed out while the Summary table is empty.

Limitations

Fit cannot open the file again.

Quit

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

File > Quit closes Fit, asking first whether to save unsaved work.

It does the same as closing the window. If the project has unsaved changes you are asked whether to save them, and the window stays open if you cancel or the save does not happen.

On closing, Fit writes its settings file: the project that was open, the recent projects and your other preferences.

The compute server is not stopped: it stays running so that the next start is immediate and other windows keep their engine.

The shortcut is Ctrl+Q, on macOS Command+Q.

Sample data

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

Fit comes with a few data files to try it on, in a folder called Data.

1.dat - a whole diffraction pattern, 1692 points with arguments from 3.0 to 172.1 in steps of 0.1.
2.dat to 9.dat - short stretches of 20 to 70 points, each around one or a few peaks. 2.dat, with two overlapping peaks between 116 and 121, is a good first fit.
sample-ohlc.csv - a daily price series with Date, Open, High, Low, Close and Volume columns.
test_data.zip - the nine .dat files packed in one archive.

Where the folder is: on Windows, beside Fit.exe in the folder Fit was installed to, which is where File > Import Profile starts; on Linux, /usr/share/fit/Data (the package's own name in place of fit for another package); on macOS, in the Resources folder inside the application bundle.

Command-line options

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

Fit's window accepts a few switches that say what to open at start-up and how much to log.

A switch starts with / (or \), is written in capitals as below, and takes its value after an equals sign, for example /PROJECT=C:\work\sample.fitproj. Put quotes around a path with spaces. A relative path that is not found is tried again relative to the folder Fit is installed in.

/PROJECT=file opens that project. It wins over everything else. If the file is not there, Fit starts with nothing open and says so in the log; it never opens a different project instead.
/INFILE=file starts a new project with that data file imported. It wins over the project remembered from last time.
With neither, the project open when Fit was last closed is opened again.
/LOG_LEVEL=level sets how much goes to the log: fatal, warning, notification, debug or trace. The default is debug, which already records almost everything, so the switch mostly makes the log quieter; trace adds the most repetitive lines as well. An unknown level is reported in the log and the default kept.
/WRITE_PARAMS_LOG writes to the log every value assigned to a parameter of a user-defined curve.
/DPI=number sets the screen resolution the window is scaled for, in pixels per inch, for a display that does not report it correctly.
/CHECK_UI is for the program's developers: the window checks its own layout and behaviour, runs a fit, writes the results to the log and closes.

The window ignores an argument that is not a switch, such as a bare file name. The installed launchers turn a bare file name into /PROJECT for a .fitproj file and /INFILE for any other file, which is how opening a project from the desktop works.

The compute server, fit_server, has options of its own: --host and --port for where it listens (127.0.0.1 and 8787 by default), --log-level, and --verbose to echo its log to the console.

Limitations

A misspelt switch is ignored without a message, and switch names are matched in capitals only.

Log files

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

The window and the compute server each keep a log file, which is where to look when something went wrong.

Both files are in Fit's folder for the current user: on Windows %APPDATA%\Fit, on Linux and macOS a folder called Fit in your home folder. The window writes fit_client.log and the server writes fit_server_log.txt - when the server runs on this computer under your account, which is how the launchers start it.

By default the logs record what you did, what the window asked the server and how long each call took, warnings and errors with the program location where they happened. Some notices go only to the log, among them a remembered project that could not be found at start-up, a data file that has changed since a project was saved, and rows skipped while reading a price file.

A log that reaches 32 MB is renamed with .1 added to its name, replacing the previous .1 file, and a new one is started. So the two most recent files of each log are kept, and nothing older.

The launchers on Linux and macOS also keep what the server prints to its console: on Linux in ~/.local/share/<package>/server.log, on macOS in ~/Library/Logs/<application>/server.log.

When you report a problem, attach both log files: each tells one side of the story, and a call can be matched on both sides by its time.

What Fit remembers between sessions

This software's choice — A decision made by this software rather than by the field's sources; the explanation says why it was made.

Some choices belong to you rather than to a project, and Fit keeps them in a settings file of its own.

The file is config.xml, in the same folder as the log files, and it is written when the window closes. It holds:

the project that was open, and the list behind File > Open Recent;
the compute server's address;
the curve type, the minimizer, the loss function and the weighting last chosen;
the argument axis, whether you chose it yourself, and a custom axis you defined;
whether Animation Mode is on.

A project carries its own copy of the fit settings, so opening a project sets them as they were when it was saved.

Limitations

If Fit ends without closing its window normally, changes since the start of the session are not written to the file.

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