Is there a way to execute two for-loops at once?

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James Lindsey 2022-2-17

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1652635-is-there-a-way-to-execute-two-for-loops-at-once

评论： James Lindsey 2022-2-21

SampleData2.mat

For instance, in the loops below, I want the equations to be executed for the first column of both the SetNo and PhaseNo arrays. In other words when SetNo=1 and PhaseNo=1, then I need the counters to move to the 2nd column of each array when SetNo=3 and PhaseNo=1. The next few iterations would be as follows:

3rd iteration: SetNo=9 and PhaseNo=1

4th iteration: SetNo=9 and PhaseNo=2

5th iteration: SetNo=9 and PhaseNo=3, and so on.

I'm reusing the LC1max, LC2max, etc. variables so at the end of each iteration, I'd like to save based on the set and phase number. For instance, when SetNo=9 and PhaseNo=2, the variables would look like: LC1max_9_2, LC2max_9_2 , etc.

load SampleData2
SetNo=[1 3 9 9 9 10 10 10 45 46 49 49 49 50 50 50 51 51 51 52 52 52 53 54 57 58 59 60];
PhaseNo=[1 1 1 2 3 1 2 3 1 1 1 2 3 1 2 3 1 2 3 1 2 3 1 1 1 1 1 1];
for ii=1:length(SetNo);;
    for jj=1:length(PhaseNo);
        chosenSetNo = SetNo(ii);
        chosenPhaseNo = PhaseNo(jj);
        idx = data.('Set No.') == chosenSetNo & data.('Phase No.') == chosenPhaseNo;
        data_1 = data(idx,:);
        LC1 = data_1([],:);
        LC2 = data_1([],:);
        LC3 = data_1([],:);
        LC4 = data_1([],:);
        LC5 = data_1([],:);
        LC6 = data_1([],:);
        LC7 = data_1([],:);
        
        %METHOD 1: LOGICAL INDEXING METHOD | This method helps save memory and
        %possible errors.
        LC1 = data_1(contains(data_1{:,4},"NESC 250B"|"NESC Insul"),:);
        LC2 = data_1(contains(data_1{:,4},"Hurr"|"RULE 250C Insul"),:);
        LC3 = data_1(contains(data_1{:,4},"Rule 250D"|"RULE 250D Insul NA+"|"RULE 250D Insul NA-"),:); 
        LC4 = data_1(contains(data_1{:,4},"Normal"),:);
        LC5 = data_1(contains(data_1{:,4},"2%"),:);
        LC6 = data_1(contains(data_1{:,4},"NESC 250B NL-, DE"|"NESC 250B NR-,DE"|"NESC 250B BI-, DE"),:); 
        LC7 = data_1(contains(data_1{:,4},"Rule 250D BI-, DE"|"Rule 250D NL-, DE"|"Rule 250D NR-, DE"),:);
        %Delete the extra rows in LC1 & LC3 that apply to the full break cases for NESC 250B & Rule 250D
        LC1([9,10,11],:) = [];
        LC3([7,8,9],:) = [];
        
        %Extract the rows that correspond with the maximum resultant in each load
        %case.
        [~,LC1MaxRes] = max(LC1.resultant);
        LC1max = LC1(LC1MaxRes,:);
        [~,LC2MaxRes] = max(LC2.resultant);
        LC2max = LC2(LC2MaxRes,:);
        [~,LC3MaxRes] = max(LC3.resultant);
        LC3max = LC3(LC3MaxRes,:);
        [~,LC4MaxRes] = max(LC4.resultant);
        LC4max = LC4(LC4MaxRes,:);
        [~,LC5MaxRes] = max(LC5.resultant);
        LC5max = LC4(LC5MaxRes,:);
        [~,LC6MaxRes] = max(LC6.resultant);
        LC6max = LC6(LC6MaxRes,:);
        [~,LC7MaxRes] = max(LC7.resultant);
        LC7max = LC7(LC7MaxRes,:);
        
        LC1max_ii_jj = LC1max;
        LC2max_ii_jj = LC2max;
        LC3max_ii_jj = LC3max;
        LC4max_ii_jj = LC4max;
        LC5max_ii_jj = LC5max;
        LC6max_ii_jj = LC6max;
        LC7max_ii_jj = LC7max;
    end
end

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David Hill 2022-2-17

Do yu have the Parallel Computing Toolbox? Look at parfor()

James Lindsey 2022-2-17

Unfortunately I do not have the Parallel Computing Toolbox

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Answer 1

Voss 2022-2-17

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1652635-is-there-a-way-to-execute-two-for-loops-at-once#answer_898960

在 MATLAB Online 中打开

You can use a single for-loop:

SetNo=[1 3 9 9 9 10 10 10 45 46 49 49 49 50 50 50 51 51 51 52 52 52 53 54 57 58 59 60];
PhaseNo=[1 1 1 2 3 1 2 3 1 1 1 2 3 1 2 3 1 2 3 1 2 3 1 1 1 1 1 1];
for ii = 1:numel(SetNo)
    % do something with SetNo(ii) and PhaseNo(ii)
end

And use the same index ii for indexing the result variables rather than using variables with different names.

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Voss 2022-2-18

编辑：Voss 2022-2-18

在 MATLAB Online 中打开

My last comment was intended to say, basically don't do what you have in mind, as far as naming variables like LC1max_1_1, LC1max_3_1, LC1max_9_1, LC1max_9_2, etc.

Here are some reasons why.

Instead you can make a single variable, say a cell array called LC1max, and calculate one element of it each time through your loop. The index of that element will be the value of the loop iterator variable ii at that iteration of the loop. For instance:

SetNo=[1 3 9 9 9 10 10 10 45 46 49 49 49 50 50 50 51 51 51 52 52 52 53 54 57 58 59 60];
PhaseNo=[1 1 1 2 3 1 2 3 1 1 1 2 3 1 2 3 1 2 3 1 2 3 1 1 1 1 1 1];
LC1max = cell(1,numel(SetNo));
for ii = 1:numel(SetNo)
    % do something with SetNo(ii) and PhaseNo(ii)
    [~,LC1MaxRes] = max(LC1.resultant);
    LC1max{ii} = LC1(LC1MaxRes,:);
end

The same logic applies to the seven sets of variables you have here LC1, LC2, ..., LC7 and their corresponding *max, *maxRes variants. You can do the same thing for everything, just use a 2D cell array with 7 columns, say, LCmax:

SetNo=[1 3 9 9 9 10 10 10 45 46 49 49 49 50 50 50 51 51 51 52 52 52 53 54 57 58 59 60];
PhaseNo=[1 1 1 2 3 1 2 3 1 1 1 2 3 1 2 3 1 2 3 1 2 3 1 1 1 1 1 1];
LCmax = cell(numel(SetNo),7);
for ii = 1:numel(SetNo)
    % do something with SetNo(ii) and PhaseNo(ii)
    
    % combine LC1-LC7 into a cell array so that they can be processed in a
    % loop below:
    LC_all = {LC1 LC2 LC3 LC4 LC5 LC6 LC7};
    for jj = 1:numel(LC_all)
        %Extract the rows that correspond with the maximum resultant in each load
        %case.
        [~,MaxResIdx] = max(LC_all{jj}.resultant);
        LCmax{ii,jj} = LC_all{jj}(MaxResIdx,:);
    end
    
end

Then later when you need to access that stuff, you can get the right element of LCmax using SetNo and PhaseNo:

wanted_SetNo = 10;
wanted_PhaseNo = 1;
my_result = LCmax(SetNo == wanted_SetNo & PhaseNo == wanted_PhaseNo,:);
% my_result is a 1-by-7 cell array containing all 7 results 
% (assuming wanted_SetNo and wanted_PhaseNo are in SetNo and PhaseNo, respectively)

Voss 2022-2-18

在 MATLAB Online 中打开

Maybe better for your purposes is to use an array of structs, which can store the SetNo and PhaseNo values associated with each result:

SetNo=[1 3 9 9 9 10 10 10 45 46 49 49 49 50 50 50 51 51 51 52 52 52 53 54 57 58 59 60];
PhaseNo=[1 1 1 2 3 1 2 3 1 1 1 2 3 1 2 3 1 2 3 1 2 3 1 1 1 1 1 1];
LCmax = cell(1,7);
results = repmat( ...
    struct('SetNo',[],'PhaseNo',[],'LCmax',[]), ...
    1,numel(SetNo));
for ii = 1:numel(SetNo)
    
    results(ii).SetNo = SetNo(ii);
    results(ii).PhaseNo = PhaseNo(ii);
    
    % do something with SetNo(ii) and PhaseNo(ii)
    
    % combine LC1-LC7 into a cell array so that they can be processed in a
    % loop below:
    LC_all = {LC1 LC2 LC3 LC4 LC5 LC6 LC7};
    for jj = 1:numel(LC_all)
        %Extract the rows that correspond with the maximum resultant in each load
        %case.
        [~,MaxResIdx] = max(LC_all{jj}.resultant);
        LCmax{jj} = LC_all{jj}(MaxResIdx,:);
    end
    
    results(ii).LCmax = LCmax;
    
end

Then you can access specific results like this:

wanted_SetNo = 10;
wanted_PhaseNo = 1;
my_result = results([results.SetNo] == wanted_SetNo & [results.PhaseNo] == wanted_PhaseNo).LCmax;
% Again assuming wanted_SetNo and wanted_PhaseNo are valid

That way you don't have to keep the SetNo and PhaseNo arrays around since everything is in the struct array 'results'.

James Lindsey 2022-2-21

Thank you. This has been very helpful. One reason I was thinking about keeping them separate and naming them "LC1_1_1" is because I'll need to sum the elements. For instance, Set 1, Phase 1's values need to be summed with Set 3, Phase 1's values (columns titled Structure Loads Vert., Structure Loads Trans. and Structure Loads Long.) for each load case. How can I call or access the cells/values I need from the array titled "results" ?

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