To query the array layout of a function at compile time, usecoder.isColumnMajororcoder.isRowMajor. 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％执行此代码，如果行专业S = 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 functionbar:

functionbar coder.columnMajor; x = magic(3);ifcoder.isColumnMajor(x) fprintf('This will always be displayed in generated code.\n');elsefprintf('这将永远不会以生成的代码显示。\ n');endend

Generate code:

codegenbar

To run the MEX function, enter:

bar_mex