Thistle by Praxik

Engineering calculations, connected

Write the relationships. Explore the solution.

Thistle is a focused desktop application for engineering calculations. Describe a system with equations, attach units, use thermodynamic properties, and solve the connected model in one place.

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simple-system.eqs Ready
Equations
  1. x + y = 10
  2. x - y = 2
  3. // solve together
Results Solved
x
6
y
4

Residuals within tolerance

Local calculations Models are evaluated on your device. No account required Open Thistle and start working. No advertising or tracking Your work is not an advertising profile.

A practical calculation workspace

Keep the model close to the way you understand it.

Thistle brings equations, variables, units, and property data into one workspace so you can concentrate on the system rather than the mechanics of rearranging it.

Connected equations

Enter the relationships that define the problem. Thistle solves them simultaneously, including nonlinear systems.

x + y + z = 12 2 × x - y + z = 7 x + 2 × y - z = 6
x = 3
y = 4
z = 5

Units in context

Attach units directly to values, review units alongside variables, and keep dimensional meaning visible.

F = m × a m = 10 |kg| a = 2 |m/s^2|
F = 20 |N|

Thermodynamic properties

Use fluid-property functions inside the same model as the rest of the engineering calculation.

T = 300 |K| P = 1 |atm| h = enthalpy(Water, P=P, T=T)
h = 112.65 |kJ/kg|

Robust solver controls

Thistle provides robust initial guesses, physical bounds, and implicit variable units. These can be updated by the user if desired.

T |K|
Guess
300
Lower
—
Upper
—
P |atm|
Guess
1
Lower
—
Upper
—
h |kJ/kg|
Guess
112.65
Lower
—
Upper
—

How it works

From a model to a checked result.

A compact workflow keeps the equations, solver inputs, and results visible at each step.

  1. 1

    Enter equations

    Put one equation on each line and describe the relationships naturally.

  2. 2

    Review variables

    Check initial guesses, physical bounds, and units before solving.

  3. 3

    Solve together

    Choose Solve or press ⌘/Ctrl + Enter.

  4. 4

    Check the result

    Review residuals, units, assumptions, and physical meaning.

Readable by design

Write calculations the way you discuss them.

Thistle syntax stays compact enough for quick work and expressive enough for connected engineering models.

  • x + y = 10 Equations are solved simultaneously.
  • T = 300 |K| Units appear between vertical bars.
  • // note Double slashes begin a comment.
  • T[1] = 300 Brackets create indexed variables.

Working examples

Start with a clear pattern.

Copy an example into Thistle, then adapt the values and relationships to your own calculation.

Simultaneous

Linear system

Solve two connected equations together.

x + y = 10
x - y = 2
Unit-aware

Engineering values

Attach units directly to the values they describe.

P = 101.325 |kPa|
V = 0.5 |m^3|
T = 300 |K|
Property data

Thermodynamics

Use a fluid-property function inside the model.

P = 100 |kPa|
T = 373.15 |K|
h = enthalpy(Water, P=P, T=T)

Local by design

Your engineering work stays under your control.

Thistle performs calculations locally, does not require an account, and stores project files only where you choose to save them.

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Thistle support

Questions should have a practical next step.

Find troubleshooting guidance, common questions, and direct contact information for the people who build Thistle.

Go to Thistle Support