Efficient way to chain element-wise operations for code generation?

Hi, I have functions that chain elementwise array operations eg:

function y = Foo(X)
y = 20*log10(abs(X));
end

I want to use Matlab Coder to make C code out of this.

I inspect the C code generated.

It performs all the sub-expressions as their own separate loops like:

//Pseudocode:
for (loop over array){
    Y = abs(X)
}
for (loop over array){
    Y = log10(Y)
}
for (loop over array){
    Y = 20.0f * Y
}

is there any way to fuse all these into 1 loop (as shown below) without manually editting the generated code:

for (loop over array){
     Y = 20.0f * log10(abs(X))
}

I'm hoping for something like an elementwise functor mapped across an array like arrayfun, but I haven't been able to get anything working.

Answer 1

[Gershom Agim]

My (really inelegant) solution to this is to create the result array outside the function, and pass that in as an argument, then explicitly write out the for-loops.

Eg:

function  Y  = Foo(X,Y)
    % Assert sizes here so codegen knows
    for i=1:size(X,1)
        for j=1:size(X,2)
            Y(i,j) = 20*log10(abs(X(i,j)));
        end
    end
end

Is there a better way of doing this?