CompPad

CompPad allows you to create technical calculations in the form of conventional-looking mathematical expressions using the LibreOffice equation editor. This editor has a simple text syntax that some consider to be faster and more intuitive than other equation editors. Then, with the click of a toolbar icon, CompPad will evaluate the expressions and display the results, embedded in your document. All of the features of LibreOffice are available for documenting and formatting your document so that it can be presented with pride to co-workers, customers, professors, etc.

Example

Here is an example of how you might use CompPad. It is a simple mechanical harmonic oscillator example based on the Wikipedia topic . You can download this example here: example - harmonic oscillator.odt.

• Install the CompPad extension (easy, see below.)
• Open a new LibreOffice Writer document. Open the CompPad sidebar with "View" -> "Sidebar", then click the CompPad icon in the sidebar's tab bar. It has three sections: Edit Expression, a resizable multi-line box for typing formulas; Palette, which is described below; and Resources, with a link to this site and a button that opens the demo document.
• A toolbar is available as well, with a single-line edit field and the same buttons: . Either surface will do - the steps below work the same way in both.
• First we define the mass of the oscillator. Type the following into the sidebar's Edit Expression box, or into the toolbar edit field : (without quotation marks) "M:=10 kg"
• Press "enter" or click . In the sidebar the box holds as many lines as you like: "enter" applies the formula, and "ctrl+enter" starts a new line. The following formula will be created:
  
• Use the mouse to move the cursor to a point after the formula. Now you can create another formula or edit text.
• Define the spring constant: "K:= 4 lbf/inch"
  
  If you are not sure how a unit is spelled - it is inch, not in - open the Palette section of the sidebar and pick it from a group: Length, area, volume & angle holds inch, and Mass, force & pressure holds lbf. Clicking a button inserts the correct spelling where the cursor is, and hovering over one says what the unit is. The palette also carries the Greek letters, the operators and brackets, the matrix notation, the functions and the display settings.
• Calculate the natural frequency of the oscillator: "f_n := 1 over {2 %pi} sqrt{ K over M}="
  
• To evaluate the expressions you've entered so far, click . You will see that the last expression gets updated with the result of the calculation:
  
  Notice how the units of measure were handled automatically. Even though we entered quantities in both SI and US Customary units, the correct solution was computed.
• Define the amplitude of the oscillation: "A:= 2 cm"
  
• Define position as a function of time: "x(t) := A cos left( sqrt{K over M } t right)"
  
• Create a time vector with 21 elements, ranging from 0 to 1 s: "t:={0 dotslow 20} over 20 s"
  
• Then calculate the position vector: x_t:= x(t)
  
• To plot position vs. time: "plotxy(t,x_t)"
• Finally, click . You will see the following plot added to the document:
  
  

Now, you can add text, pictures, formatting, and other elements using all of the features of LibreOffice Writer. If you need to change a parameter in the calculation, you can make your changes using the equation editor, and then to re-evaluate the document.

CompPadDemo.odt demonstrates all the features of CompPad in a writer document. Also, check out the example files.

Screenshots

Installation

• All releases are available HERE.
• New users should download the most recent .oxt from the "0.5" branch - this is the current release and the default download.
• In LibreOffice, installing the extension for the first time should be as simple as opening the .oxt file using "File" -> "Open", or via "Tools" -> "Extension Manager".
• After installing, you will need to re-start LibreOffice.
• If you are upgrading from a previous version of CompPad, the above procedure should work. If you have any trouble, post a message on the Discussion Forum

The latest releases (0.5.x) are implemented in Python and do not require a Java runtime - they use the Python support built into LibreOffice, and have been tested with LibreOffice 26.2. They should run on Windows, Linux, macOS, and other operating systems that support LibreOffice.

Using CompPad

• Try the example above
• For a document with an extensive list of examples, download CompPadDemo.odt . This file demonstrates most of the features of CompPad and should help you get started.
• Try changing the expressions in these examples, or create a new document with your own expressions. If you get an error, double-check the offending formula.
• If you're stuck, search the Discussion Forum to see if your question has already been answered.
• Post questions, bug-reports and feature requests to the Discussion Forum .

Example Files

CompPadDemo.odt is a document which contains examples of most CompPad features.

example - fluid mechanics.odt

Current Status

CompPad is usable and has been reportedly used to evaluate documents with hundreds of formulas. Every release is covered by an automated suite of over 1,300 tests, and the calculation engine is tested on its own, independently of LibreOffice.

Here are a few of the features that are supported in the most recent version:

• A sidebar holding a resizable, multi-line expression editor, a palette, and a button that opens the demo document. A toolbar with a single-line edit field is available as well.
• A palette of the things that are hard to guess at: every unit CompPad knows, grouped by what it measures; the Greek letters; the operators and brackets; the matrix notation; the functions; and the display settings. Clicking an entry inserts it where the cursor is, spelled correctly, and wraps or follows whatever text is selected.
• Single-line function definition
• Real and Complex numbers, booleans, vectors and matrices
• Units of measure are handled in all quantities and calculations. Supported units are listed here: UNITS.md
• Units are displayed according to the specified system of units. Options are "SI","US","CGS".
• Temperatures can be written the way they are spoken - T := 70 degF - and a temperature is distinguished from a temperature interval (deltaDegC, deltaDegF).
• Linear algebra: determinant, inverse, and the solution of a linear system (det(A), inv(A) or A^-1, lsolve(A,b)).
• Vector / matrix operators including transpose, dot product, norm, min, max, sum and product. Scalar functions are applied element by element.
• |X| follows the shape of what it encloses - the absolute value of a number, the magnitude of a vector, the determinant of a square matrix.
• Conditionals, with any number of cases.
• Basic operators including arithmetical, exponential, comparison, rounding, trigonometric, hyperbolic, logarithmic, and roots of any degree.
• Range variables, with an explicit step if you want one: first, second dotslow last
• Support for alternate decimal separators - either "." or ","
• Basic X-Y plotting
• Complex variable names consisting of almost any combination of text or formula element.
• Changing expression color
• Blocking evaluation of an expression.
• Setting the number of displayed significant figures or decimal places, and a threshold below which a result is shown as zero.
• import expressions from a text file.
• The user interface is translated into nine languages: English, German, Spanish, French, Italian, Dutch, Greek, Ukrainian and Simplified Chinese.

If you require a certain feature for CompPad to be useful to you, please let me know. I may be able to give it priority.

Development

CompPad is being actively developed.

Following are a few features I hope to implement eventually:

• Numerical calculus: definite integrals and derivatives, in the correct derived units.
• Scope blocks and function blocks - turning a Writer frame into a scope of its own, so that a calculation can show its working without its intermediate names escaping into the rest of the document.
• A more complete set of built-in functions and operators.
• Control structures such as loops.
• Import expressions from other documents
• Read from and write to cells in LibreOffice Calc.
• Plug-in framework for adding new functions, operators, etc.
• Web interface

Contribute

Currently the best way to contribute is to try out CompPad, and post your question and comments to the Discussion Forum. Your comments help me know what is important to users. I would especially like to know how you would like to use CompPad. If you require a certain feature in order for CompPad to be useful to you, then let me know. I may be able to give it priority.

License

Source code is provided under the terms of the GPL Ver. 3. It is available through GIT on the Sourceforge Project Page.

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