## EvalEquation

Version 1.0.7 (5.4 KB) by
This function can be used to evaluate an (list of) equation(s) written as string (char-array). It is based on the Shunting-yard algorithm

Updated 13 Aug 2018

This function can be used to evaluate an equation written as string (char-array).
The basis of the function is the Shunting yard algorithm, as in the C#
example of: https://rosettacode.org/wiki/Parsing/Shunting-yard_algorithm

The shunting-yard algorithm is a method for parsing mathematical expressions
specified in infix notation to postfix notation.

Example

result = EvalEquation( '1+2/(2*3)');
disp(result)
1.3333

or with variables,

result = EvalEquation( 'y+x/(2*3)','x',2,'y',3);
disp(result)
3.3333

Supported operators: ^ * / + - ( ) > < == >= <=
Supported functions: sqrt abs sin cos tan asin acos atan exp sign round floor ceil
max(a,b) min(a,b)
Supported constants: pi
************************************************************************************************************************************

This function EvalEquationScript can be used to evaluate a list of equations
and finaly return one of the variables as result

result = EvalEquationScript(script, output_variable_name, variable1, value1, variable2, value2,....)

Example,

script = cell(5,1);
script{1}='a=1';
script{2}='b=a*2';
script{3}='%Calculate max of a,b time x';
script{4}='x=x+a';
script{5}='c=max(a,b)*x';

result = EvalEquationScript(script,'c','x',3);

### Cite As

Dirk-Jan Kroon (2023). EvalEquation (https://www.mathworks.com/matlabcentral/fileexchange/68458-evalequation), MATLAB Central File Exchange. Retrieved .

##### MATLAB Release Compatibility
Created with R2018a
Compatible with any release
##### Platform Compatibility
Windows macOS Linux

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Version Published Release Notes
1.0.7

Fixed bug in parsing a number like -1.e-31

1.0.6

1.0.5

1.0.4

1.0.3

Now explicit support of arrays as value of an input variable.
Also made compatible with Matlab Coder

1.0.2

Support for more operators and functions

1.0.1

Added supported functions: sqrt abs sin cos tan asin acos atan exp

1.0.0