Least Squares Curve Fit5.6 - App Store

“Least Squares Curve Fit” is a user friendly, free of charge and free of ads app.
User inputs point sets and chooses function types.
Utilizing the Least Squares Linear Regression Method, the app calculates best fit curves, reports equations and draws graphs.
Point sets can be stored in a table and are available after app is closed.

Currently available function types are:

2D:
1. Line.
2. Parabola.
3. Polynomial up to 8th degree.
4. Circle.
5. Conic section (Ellipse or Hyperbola).
6. Trigonometric function as
C + A1*cos(ω*x) + B1*sin(ω*x) + ... + An*cos(n*ω*x) + Bn*sin(n*ω*x),
where user can select n between 1 and 8 and enter any ω.
7. Exponential Function.
8. Bell Curve.

3D:
1. Plane.
2. Sphere.

Also, there is an option to choose the Best Fit:
the app goes through all the possible shapes and lists them in order from best to worst fit based on residuals.

In some cases, when the standard Least Squares method with orthogonal projection does not work, best fit for Line, Parabola, Polynomial and Trigonometric functions can be calculated with SVD.

Links to four other free apps by same developers are included in the app:
1. “Matrix Solver Step by Step” Linear Algebra Visual Guide.
2. “Polynomials and Linear Systems” Equation Solver.
3. “GraphMath” Graphing Calculator.
4. “Vectors and Planes” (and Spheres and Ellipsoids) 3D Geometry Guide.

Developers hope to get feedback from users at graphmath@aol.com.

Version History Bug fixes and crash prevention 5.6 05/29/2025 1. Link to our new app: 'Construct Polynomial: Interpolate & Approximate'.
2. Bug fixes and UI improvements. 5.5 02/13/2025 Link to our new app: 'Polynomial Solver Step by Step', which will replace 'Polynomials and Linear Systems'. 5.4 11/16/2024 1. Link to our new app: "Calcu-Logarithm", all about logarithms, from arithmetic to calculus.
2. Bug fixes and crash prevention. 5.3 09/25/2024 1. Links to our new apps:
* 'Drawing with Math' (Vector & Pixel Art),
* '3D Rotations & Quaternions',
* 'Base to Base' (Number Converter).
2. UI and performance improvements. 5.2 09/16/2024 1. Blank coordinate fields can be filled with random entries. Range choices are provided.
2. Process improvements and bug fixes. 5.1 01/29/2023 Bug fix and prevention 5.0.1 12/18/2022 1. Next 3D approximation shape: Sphere.
2. Bug fixes and UI improvements 5.0 12/16/2022 Link to Linear Algebra app (Matrix Solver Step by Step) with instructions on solving Least Squares problems 4.1 12/07/2022 Added the first 3D item: Plane. 4.0 11/20/2022 Bug fixes 3.2.2 11/15/2022 Bug fix 3.2.1 11/13/2022 1. Residuals can be shown and hidden on the graph.
2. Best fit can be calculated with SVD for Line, Parabola, Polynomial and Trigonometric functions, when the standard Least Squares method with Orthogonal Projection does not work.
3. UI improvements and bug fixes. 3.2 11/11/2022 1. Added new Zoom Options, to zoom separately by X or Y.
2. UI improvements and bug fixes. 3.1 11/06/2022 Added a new Option to choose the Best Shape:
the App goes through all the possible shapes
and lists them in order from best to worst fit based on residuals. 3.0 10/24/2022 UI improvements and bug fixes. 2.2 10/19/2022 Bug fix 2.1.1 10/18/2022 1. 'Bell Curve’ graph has color-coded areas for 1, 2 and 3 Standard Deviations.
2. Added a table with coordinates and residual data for each point.
3. Point sets can be pasted from other apps, such as Pages and Numbers.
4. New controls to scroll points UI up/down: 1 line, 1 page (4 lines), Top/Bottom.
5. Option to remove a point by swiping left.
6. Maximum number of points increased to 200.
7. Bug fixes and UI Improvements. 2.1 10/17/2022 1. Added two new shapes: 'Exponential Function’ and 'Bell Curve'.
2. Bug fixes. 2.0 10/09/2022 Bug fixes 1.0.1 09/29/2022 1.0 09/26/2022