v0.8.0

Changelog:

• Change log(x) to be base 10 by default. Other bases can be specified using log(x, b) or the natural logarithm with ln(x).
• Support for abbreviated inverse trig function names: asin(...) etc.
• Add a "syntax_error" key to the result dictionary, if the input test string contains invalid syntax.
• Better replacement of Unicode characters based on their names.
• Fix an issue where 2l or 2L was interpreted as a numeric long, not as multiplication of a symbol.
• Rename result keys to be consistently in snake_case.

v0.7.0

Changelog:

• Use Gunicorn to serve requests in production, rather than relying on the builtin Flask server explicitly not intended for production use.
• Fix an issue whereby derivatives were simplified despite an attempt at disabling this. There is now a global constant to enable/disable this, which needs refactoring as an argument to check(...).
• Fix a bug when checking differential equations that contained multiple derivatives of different orders, where the inner lower-order derivatives were replaced too early.
• Correctly parse relations (=, <, <= etc) rather than replace them using a regular expression.
• Refactoring of unit tests to separate out functionality.
• Update to use SymPy version 1.2 and newer versions of other dependencies.

v0.6.0

Changelog:

• Ignore symbols prefixed with an underscore when processing provided custom symbols. This allows metasymbols to be included without having to remove them before passing to the checker.

v0.5.0

Changelog:

• Allow numeric input to include decimal points without a number before them: e.g. .5 as well as 0.5.
• Prevent attempts to parse empty strings.

v0.4.0

Changelog:

• Improved support for custom symbols; functions and operators can be passed without breaking anything, and those which are not valid Python variables will be (silently) ignored. This allows functions and operators relevant to an expression/equation to be included without breaking anything.
• Update dependencies, notably sympy from 1.0 to 1.1.1.
• Fix an issue with complex infinity in numeric checking code.

v0.3.0

Changelog:

• Much more effectively sanitise untrusted input, especially Unicode input and Python keywords.
• Allow diff(...) syntax for derivatives.
• Allow Mathematica style function names: Sin(...), Cos(...) etc.
• Allow function exponentiation: cos**2(x) for cos(x)**2 for instance.

v0.2.0

Changelog:

• Split out the parsing into another file and use a slightly modified version of the SymPy parsing code to prevent evaluation of function arguments. This allows the parser to distinguish cos(x) and cos(-x) for instance.
• Remove support for factorials until better integration with numeric testing can be added.
• Add clearer README and LICENSE files.
• Deprecate Vagrant requirement, move directly to Docker.

v0.1.0

First production ready release, ran on live server from October 2016 to June 2017.

Supported Functions and Operations

Standard Operations

• Addition (+)
• Multiplication (*, implicitly xy, implicitly x y)
• Exponentiation (**, ^)
• Unary Negation (-)

Where division and subtraction are expressible in terms of the above

Numbers

• Integers (0, 1, -1, ...)
• Decimals (0.123, ...)
• Rational Numbers (1/2, ...)

Trigonometic Functions

• Standard trig functions (sin(), cos(), tan())
• Inverse trig functions (arcsin(), arccos(), arctan())
• Reciprocal trig functions (cosec(), sec(), cot())
• Inverse reciprocal trig functions (arccosec(), arcsec(), arccot())
• Hyperbolic trig functions (sinh(), cosh(), tanh())
• Inverse hyperbolic trig functions (arcsinh(), arccosh(), arctanh())
• Reciprocal hyperbolic trig functions (cosech(), sech(), coth())

No inverse reciprocal hyperbolic trig functions

Logarithms and Exponentials

• Exponential function (exp())
• Natural logarithm (ln(), log())
• Logs to other bases (log(x, base))

Other Basic Functions

• Square root (sqrt())
• Modulus (abs())

Calculus

• Derivatives (Derivative(y, x), Derivative(y, x, 2), Derivative(y, x, x), ...)

Equations and Inequalities

• Equations (x == y)
• Inequalities (x < y)