coder.rowMajor - Specify row-major array layout for a function or class - MATLAB (original) (raw)

Main Content

Specify row-major array layout for a function or class

Syntax

Description

coder.rowMajor specifies row-major array layout for the data used by the current function in generated code. When placed in a class constructor,coder.rowMajor specifies row-major layout for data used by the class.

Note

By default, code generation uses column-major array layout.

example

Examples

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Specify row-major array layout for a function by insertingcoder.rowMajor into the function body.

Suppose that myFunction is the top-level function of your code. Your application requires you to perform matrix addition with row-major array layout and matrix multiplication with column-major layout.

function S = myFunction(A,B) %#codegen % check to make sure inputs are valid if size(A,1) ~= size(B,1) || size(A,2) ~= size(B,2) disp('Matrices must be same size.'); return; end

% make both matrices symmetric
B = B*B';
A = A*A';

% add matrices
S = addMatrix(A,B);

end

Write a function for matrix addition called addMatrix. Specify row-major layout for addMatrix by usingcoder.rowMajor.

function S = addMatrix(A,B) %#codegen S = zeros(size(A)); coder.rowMajor; % specify row-major array layout for i = 1:size(A,1) for j = 1:size(A,2) S(i,j) = A(i,j) + B(i,j); end end end

Generate code for myFunction. Use thecodegen command.

codegen myFunction -args {ones(10,20),ones(10,20)} -config:lib -launchreport

The code generator produces code for addMatrix that uses row-major array layout. However, the matrix multiplication from the top-level function uses the default layout, column-major.

Tips

To specify row-major array layout for all the functions in your generated code, use the codegen -rowmajor option.
Other functions called from within a row-major function inherit the row-major specification. However, if one of the called functions has its own distinctcoder.columnMajor call, the code generator changes the array layout accordingly. If a row-major function and a column-major function call the same function, which does not have its own array layout specification, the code generator produces a row-major version and column-major version of the function.
coder.rowMajor is ignored outside of code generation and simulation.

Extended Capabilities

Version History

Introduced in R2018a