Lib.rs

This repo/crate provides a number of math utilities:

• Parsing and evaluating expressions containing a combination of matrices, vectors and scalars.
• Solving equations and system of equations (both linear and non-linear).
• Exporting a LaTeX document from a collection of parsed and evaluated expressions.

⚠️ This repo/crate has not hit 1.0.0 yet, breaking changes are bound to happen!

Major features

• Parsing and evaluating calculations with matrices, vectors and scalars.
• A recursive parsing implementation allowing for calculations withing matrices and vectors.
• An inbuilt equation solver for solving linear and non-linear systems of equations, accessible through a custom "function".
• An evaluator based on combinatorics for combining multiple results from equations or sqrt with other operations.
• Inbuilt quality of life functions for exporting results to latex.

Usage

For usage information concerning the mathematical properties of the evaluator and more examples, please take a look at the wiki.

For programming documentation, please take a look at docs.rs

Examples

let res = quick_eval("3*3", &Context::empty())?.to_vec();
    
assert_eq!(res[0], Value::Scalar(9.));

let x = Variable::new("x", vec![Value::Scalar(3.)]);
let res = quick_eval("3x", &Context::from_vars(vec![x]))?.to_vec();

assert_eq!(res[0], Value::Scalar(9.));

let res = quick_eval("[[3, 4, 5], [1, 2, 3], [5, 6, 7]]", &Context::empty())?.to_vec();

assert_eq!(res[0], Value::Matrix(vec![vec![3., 1., 5.], vec![4., 2., 6.], vec![5., 3., 7.]]));

let function = parse("5x^2+2x+x")?;
let function_var = Function::new("f", function, vec!["x"]);

let res = quick_eval("f(5)", &Context::from_funs(vec![function_var]))?.to_vec();

assert_eq!(res[0], Value::Scalar(140.));

let res = quick_eval("eq(x^2=9, x)", &Context::empty())?.round(3).to_vec();
    
assert_eq!(res, vec![Value::Scalar(-3.), Value::Scalar(3.)]);

let equation = "eq(2x+5y+2z=-38, 3x-2y+4z=17, -6x+y-7z=-12, x, y, z)";

let res = quick_eval(equation, &Context::empty())?.round(3).to_vec();

assert_eq!(res, vec![Value::Vector(vec![3., -8., -2.])]);

let parsed_expr = parse("3*3+6^5")?;
let res = eval(&parsed_expr, &Context::empty())?;

let step = Step::Calc { term: parsed_expr, result: res, variable_save: Some("x".to_string()) };

let png = png_from_latex(step.as_latex_inline(), 200, "#FFFFFF")?;

Output:

TODO

• Support for vectors and matrices
• Calculations in vectors and matrices
• Equations as operators -> eval can handle multiple values
• Complex numbers
• Possible tensor support
• Stable API that makes everyone happy (very hard)

Issues and Contributions

When opening an issue, please specify the following:

• The mathematical expression that causes the issue
• The error (or lack of it), be it a MathLibError or any other kind of error
• The expected behavior

When it comes to contributions, feel free to fork this repo and open pull requests.