C++ Mathematical Expression Library (ExprTk) http://www.partow.net/programming/exprtk/index.html
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Arash Partow
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* C++ Mathematical Expression Toolkit Library *
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* *
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* Simple Example 9 *
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* Author: Arash Partow (1999-2012) *
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* Author: Arash Partow (1999-2013) *
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* URL: http://www.partow.net/programming/exprtk/index.html *
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* *
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* Copyright notice: *
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59
readme.txt
59
readme.txt
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@ -5,7 +5,7 @@ The C++ Mathematical Expression Toolkit Library (ExprTk) is a simple
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to use, easy to integrate and extremely efficient mathematical
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expression parsing and evaluation engine. The parsing engine supports
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numerous forms of functional and logic processing semantics and is
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very easily extendible.
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easily extendible.
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@ -61,7 +61,7 @@ expressions that can be parsed and evaluated using the ExprTk library.
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(12) (x + y)3.3 + 1 / 4.5 == (x + y) * 3.3 + 1 / 4.5
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(13) (x + y)z + 1.1 / 2.7 == (x + y) * z + 1.1 / 2.7
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(14) (sin(x / pi) cos(2y) + 1) == (sin(x / pi) * cos(2 * y) + 1)
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(15) 25x^5 - 35x^4 - 15x^3 + 40x^2 - 15x + 1
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(15) 75x^17 + 25.1x^5 - 35x^4 - 15.2x^3 + 40x^2 - 15.3x + 1
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(16) if (avg(x,y) <= x + y, x - y, x * y) + 2.345 * pi / x
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(17) fib_i := fib_i + (x := y + 0 * (fib_i := x + (y := fib_i)))
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(18) while (x <= 100) { x := x + 1 }
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@ -327,9 +327,9 @@ include path (e.g: /usr/include/).
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| [r0:r1] | The closed interval [r0,r1] of the specified string. |
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| | eg: Given a string x with a value of 'abcdefgh' then: |
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| | 0. x[1:4] == 'bcde' |
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| | 1. x[ :5] == 'abcdef' |
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| | 2. x[3: ] == 'cdefgh' |
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| | 3. x[ : ] == 'abcdefgh' |
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| | 1. x[ :5] == x[:5] == 'abcdef' |
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| | 2. x[3: ] == x[3:] =='cdefgh' |
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| | 3. x[ : ] == x[:] == 'abcdefgh' |
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| | 4. x[4/2:3+2] == x[2:5] == 'cdef' |
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| | |
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| | Note: Both r0 and r1 are assumed to be integers, where |
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@ -354,7 +354,7 @@ include path (e.g: /usr/include/).
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| | switch |
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| | { |
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| | case x > (y + z) : 2 * x / abs(y - z); |
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| | case x < 3 : sin(x + y) |
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| | case x < 3 : sin(x + y); |
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| | default : 1 + x; |
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| | } |
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+----------+---------------------------------------------------------+
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@ -389,7 +389,39 @@ include path (e.g: /usr/include/).
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[09 - SPECIAL FUNCTIONS]
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[09 - COMPONENTS]
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There are three primary components, that are specialized upon a given
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numeric type, which make up the core of ExprTk. The components are as
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follows:
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1. Symbol Table exprtk::symbol_table<T>
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2. Expression exprtk::expression<T>
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3. Parser exprtk::parser<T>
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(1) Symbol Table
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A structure that is used to store references to variables, constants
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and functions that are to be used within expressions.
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(2) Expression
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A structure that holds an AST for a specified expression and is used
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to evaluate said expression. If a compiled Expression uses variables
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or user defined functions, it will then also have an associated Symbol
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Table, which will contain references to said variables, functions et
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al.
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(3) Parser
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A structure which takes as input a string representation of an
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expression and attempts to compile said input with the result being an
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instance of Expression. If an error is encountered during the
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compilation process, the parser will stop compiling and return an
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error status code, with a more detailed description of the error(s)
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and its location within the input provided by the 'get_error'
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interface.
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[10 - SPECIAL FUNCTIONS]
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The purpose of special functions in ExprTk is to provide compiler
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generated equivalents of common mathematical expressions which can be
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invoked by using the 'special function' syntax (eg: $f12(x,y,z) or
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@ -460,7 +492,7 @@ correctly optimize such expressions for a given architecture.
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[10 - EXPRTK NOTES]
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[11 - EXPRTK NOTES]
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(00) Precision and performance of expression evaluations are the
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dominant principles of the ExprTk library.
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@ -470,7 +502,7 @@ correctly optimize such expressions for a given architecture.
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(03) Results of expressions that are deemed as being 'valid' are to
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exist within the set of Real numbers. All other results will be
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of the value Not-A-Number (NaN).
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of the value: Not-A-Number (NaN).
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(04) Supported user defined types are numeric and string variables
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and functions.
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@ -532,7 +564,7 @@ correctly optimize such expressions for a given architecture.
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[11 - SIMPLE EXPRTK EXAMPLE]
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[12 - SIMPLE EXPRTK EXAMPLE]
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--- snip ---
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#include <cstdio>
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#include <string>
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@ -586,7 +618,10 @@ int main()
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for (std::size_t i = 0; i < parser.error_count(); ++i)
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{
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error_t error = parser.get_error(i);
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printf("Err: %02d Pos: %02d Type: [%s] Msg: %s Expr: %s\n",
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printf("Error: %02d Position: %02d "
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"Type: [%s] "
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"Message: %s "
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"Expression: %s\n",
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static_cast<int>(i),
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static_cast<int>(error.token.position),
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exprtk::parser_error::to_str(error.mode).c_str(),
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@ -607,7 +642,7 @@ int main()
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[12 - FILES]
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[13 - FILES]
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(00) Makefile
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(01) readme.txt
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(02) exprtk.hpp
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