To query the array layout of a function at compile time, usecoder.isRowMajororcoder.isColumnMajor. This query can be useful for specializing your generated code when it involves row-major and column-major functions. For example, consider this function:

functionS = addMatrixRouted(A,B)ifcoder.isRowMajor%execute this code if row majorS = addMatrix_OptimizedForRowMajor(A,B);elseifcoder.isColumnMajor%execute this code if column majorS = addMatrix_OptimizedForColumnMajor(A,B);end

The functionaddMatrixRoutedbehaves differently depending on whether it uses row-major layout or column-major layout. The layout that the function uses, for example, can depend on whether it is called from a function that containscoder.rowMajororcoder.columnMajor. WhenaddMatrixRouteduses row-major layout, it calls theaddMatrix_OptimizedForRowMajorfunction, which has efficient memory access for row-major data. When the function uses column-major layout, it calls a version of theaddMatrixfunction optimized for column-major data.

By using the query functions, the generated code foraddMatrixRoutedprovides efficient memory access for either choice of array layout.

Consider the functionfoo:

functionfoo coder.rowMajor; x = magic(3);ifcoder.isRowMajor (x) fprintf('This will always be displayed in generated code.\n');elsefprintf('This will never be displayed in generated code.\n');endend

Generate code:

codegenfoo

To run the MEX function, enter:

foo_mex