Build Options¶

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When building MathExpr there are a number of defines that will enable or disable certain features and capabilities. The defines can either be part of a compiler command line switch or scoped around the include to the MathExpr header, or enabled via the same-named CMake cache variable. The defines are as follows:

1. MATH_EXPR_ENABLE_DEBUGGING
2. MATH_EXPR_DISABLE_CARDINAL_POW_OPTIMISATION
3. MATH_EXPR_DISABLE_COMMENTS
4. MATH_EXPR_DISABLE_BREAK_CONTINUE
5. MATH_EXPR_DISABLE_SC_ANDOR
6. MATH_EXPR_DISABLE_RETURN_STATEMENT
7. MATH_EXPR_DISABLE_ENHANCED_FEATURES
8. MATH_EXPR_DISABLE_STRING_CAPABILITIES
9. MATH_EXPR_DISABLE_SUPERSCALAR_UNROLL
10. MATH_EXPR_DISABLE_RTL_IO
11. MATH_EXPR_DISABLE_RTL_IO_FILE
12. MATH_EXPR_DISABLE_RTL_VECOPS
13. MATH_EXPR_DISABLE_CASEINSENSITIVITY
14. MATH_EXPR_ENABLE_RANGE_RUNTIME_CHECKS

In addition to the preprocessor-style switches above, MathExpr also accepts the CMake cache variable MATH_EXPR_EPSILON. Unlike the defines listed above, this is not a preprocessor switch. It configures the floating-point epsilon used by equal(), not_equal(), and the built-in epsilon constant.

MATH_EXPR_ENABLE_DEBUGGING¶

This define will enable printing of debug information to stdout during the compilation process.

MATH_EXPR_DISABLE_CARDINAL_POW_OPTIMISATION¶

This define will disable the optimisation invoked when constant integers are used as powers in exponentiation expressions (eg: x^7).

MATH_EXPR_DISABLE_COMMENTS¶

This define will disable the ability for expressions to have comments. Expressions that have comments when parsed with a build that has this option, will result in a compilation failure.

MATH_EXPR_DISABLE_BREAK_CONTINUE¶

This define will disable the loop-wise 'break' and 'continue' capabilities. Any expression that contains those keywords will result in a compilation failure.

MATH_EXPR_DISABLE_SC_ANDOR¶

This define will disable the short-circuit '&' (and) and '|' (or) operators

MATH_EXPR_DISABLE_RETURN_STATEMENT¶

This define will disable use of return statements within expressions.

MATH_EXPR_DISABLE_ENHANCED_FEATURES¶

This define will disable all enhanced features such as strength reduction and special function optimisations and expression specific type instantiations. This feature will reduce compilation times and binary sizes but will also result in massive performance degradation of expression evaluations.

MATH_EXPR_DISABLE_STRING_CAPABILITIES¶

This define will disable all string processing capabilities. Any expression that contains a string or string related syntax will result in a compilation failure.

MATH_EXPR_DISABLE_SUPERSCALAR_UNROLL¶

This define will set the loop unroll batch size to 4 operations per loop instead of the default 8 operations. This define is used in operations that involve vectors and aggregations over vectors. When targeting non-superscalar architectures, it may be recommended to build using this particular option if efficiency of evaluations is of concern.

MATH_EXPR_DISABLE_RTL_IO¶

This define will disable all of basic IO RTL package features. When present, any attempt to register the basic IO RTL package with a given symbol table will fail causing a compilation error.

MATH_EXPR_DISABLE_RTL_IO_FILE¶

This define will disable the file I/O RTL package features. When present, any attempts to register the file I/O package with a given symbol table will fail causing a compilation error.

MATH_EXPR_DISABLE_RTL_VECOPS¶

This define will disable the extended vector operations RTL package features. When present, any attempts to register the vector operations package with a given symbol table will fail causing a compilation error.

MATH_EXPR_DISABLE_CASEINSENSITIVITY¶

This define will disable case-insensitivity when matching variables and functions. Furthermore all reserved and keywords will only be acknowledged when in all lower-case.

MATH_EXPR_ENABLE_RANGE_RUNTIME_CHECKS¶

This define will enable run-time checks pertaining to vector indexing operations used in any of the vector-to-vector and vector-to-scalar operations.

MATH_EXPR_EPSILON¶

This CMake cache variable overrides the floating-point epsilon used by MathExpr for real-valued comparisons and for the built-in epsilon symbol table constant.

When MATH_EXPR_EPSILON is not set, MathExpr uses std::numeric_limits<T>::epsilon() for each supported real type.

When it is set, the configured scalar is cast to float, double, and long double as needed. The value must be a positive finite decimal literal such as 1e-9 or 0.125.

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