ExprCal

A compact library for compiling and solving complex mathematical expressions (still under tests). A String expression is brought into Object Model for better processing & greater readability.

Getting Started

Basic setup to get result of an expression

Initial Setup

• Install Maven
• Clone or Download the repository.
• Go to the project folder from your native terminal.
• Build and Make an usable .jar file using command mvn install
• Get the *.jar files from .../target folder.

Render an expression

String s="1.233---.999.00+sin(pow(2,PI))/cos(60)tan(45)";
int round_up_scale = 4;
double result = new ExpressionRenderer(s, ExpressionRenderer.DEGREE, round_up_scale).render().getResult();

Features

Every Expression type object has ExpressionFramgment objects in it stored into a hash-map.

Types of ExpressionFramgments:-

• Number
• Function
• Expression
• Constant
• Operator
• Sign
• Bracket

Expression types that are accepted:

• [(Number*)(Function*)(Constant*)] - [(Number*)[//*](Function*)[//*](Constant*)] (represented in regex)
• [(Number+|Function+|Constant+)Operator(Number+|Function+|Constant+)] (represented in regex)
• Number String [1.233.999.00.33] - 1.233 * 0.999 * 0.00 * 0.33
• Function inside Function i.e. f(g(X)) is accepted.
• Fragments with spaces can also be written for better expression readability.
• Number,Function,Expression,Constant fragments with multiple Sign fragments are accepted.

Constant Pool:

Constants follow Uppercase paradigm. So always declare Constants in UpperCase to avoid error.

Types of Constant declarations:-

• "X" means X=0
• "X=" means X=0
• "X=10" means X=10.0
• "X=0.0" means X=0.0
• "X=3*4+sqrt(9)" means X=15.0
• "X=A" means X=A=some pre-declared value

Constant.add("X",Constant.get("PI")); Constant.add("Y",3.0);
Constant.add("U","X=U","X=-sqrt(X)","Y=4");

ExpressionRenderer e = new ExpressionRenderer(ExpressionRenderer.DEGREE, 4);
e.add("U","X=U","X=-sqrt(X)","Y=4");

Function Pool:

static methods of any class can be inserted in the Function Pool. The first parameter should be the name with which it will be known in the pool & second should be the method itself.

But Functions follow some rules:-

• Functions follow Lowercase paradigm. So always declare Functions in Lowercase to avoid error.
• The parameters passed should be Numbers
• The return type of the Functions should be Number

Function.add("hlsin", Math.class.getDeclaredMethod("sin", double.class));

ExpressionRenderer e = new ExpressionRenderer(ExpressionRenderer.DEGREE, 4);
e.add("abs", Math.class.getDeclaredMethod("abs", double.class));

Method Chaining:

Method chaining has been introduced for some functions invoked via an 'ExpressionRenderer' object.

ExpressionRenderer e = new ExpressionRenderer(ExpressionRenderer.DEGREE, 4);
double res = e.add("U","X=U","X=-sqrt(X)","Y=4").add("abs", Math.class.getDeclaredMethod("abs", double.class)).setExpression(s).render().getResult();

Warning:

• Functions and Constants must be declared before setting the expression.
• Don't declare Constants together. viz:- don't write "PIX" write "PI*X"

Testing

Testing the library using JUnit framework.

Setting Up & Testing

• Install JUnit
• Move to the ..src\test\java\com\ruh\exprcal\test directory.
• Add test cases to A.class with Annotation @Test ; So that JUnit can recognise it as a test case.
• Compile A.java & ExprCalTest.java.
• Run ExprCalTest class.

You can also test using your own ways.