Assigning elements or an array within a Bus

Question

Paul Johnson 2021-11-18

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1589889-assigning-elements-or-an-array-within-a-bus

回答： Pramil about 4 hours 前

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Hi,

I have a Bus that is a structure of Buses where some of them are simple types with large dimensions.

E.G

"BusType1" = A bus structure with elements A,B and C of type Boolean,Boolean and Int32 respectively.

"Bus.Bus_Child_1" is of type "BusType1" with 30 Dimensions

Within my model I would like to assign some of the elelements of in Bus_Child_1.

I have currently been performing this using a matlab function within the model. Similar to this:

function Bus = fcn(DefaultBusValues,AInput,BInput,CInput)
Bus = DefaultBusValues;
for idx = 1:length(AInput)
    Bus.Bus_Child_1(idx).A = Boolean(AInput(idx));
    Bus.Bus_Child_1(idx).B = Boolean(AInput(idx));
    Bus.Bus_Child_1(idx).C = Int32(AInput(idx));
end

Using this Implementation I'm finding that the performance of my model suffers.

Is there a different implementation method that would perform better?

Thanks!

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Answer 1

Pramil about 4 hours 前

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1589889-assigning-elements-or-an-array-within-a-bus#answer_1449576

在 MATLAB Online 中打开

Hi Paul,

The method you're using for assigning values to the elements within the “Bus Structure” involves a loop to assign values to each element of the bus, which can be relatively slow, especially for large datasets or when the function is called frequently within a simulation.

You can improve the simulation speed through the following changes:

Vectorize the assignment where possible. MATLAB is more efficient at handling vectorized operations.
Minimize the overhead of type conversion functions (like Boolean and Int32) if they're not strictly necessary.

Here is an example code for the above:

% Assuming AInput, BInput, and CInput are already in the correct format and size 
% Create a temporary structure array that mirrors the bus structure 
tempStruct = struct('A', num2cell(logical(AInput)), 'B', num2cell(logical(BInput)), 'C', num2cell(int32(CInput))); 
% Assign the temporary structure array to the bus in one operation 
Bus.Bus_Child_1 = tempStruct; 

This assumes that “AInput”, “BInput”, and “CInput” are vectors of the correct size and type, and it uses “num2cell” to convert them into cell arrays that can be used to initialize a structure array matching the bus structure. This method avoids the loop entirely but requires that the data be pre-formatted to match the bus structure.

Here is a documentation link for “num2cell” function for reference:

https://www.mathworks.com/help/matlab/ref/num2cell.html

Hope it helps.