How to optimize my Matlab code ?

Question

afef 2017-4-10

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https://ww2.mathworks.cn/matlabcentral/answers/334714-how-to-optimize-my-matlab-code

评论： afef 2017-5-21

Hi , i have written this Matlab code but i realize that's a little long so i want to optimize it but i don't know how . Can anyone help me please?

 clc;
 clear all;
 close all;
 load('C:\Users\del.dell-PC\pfe\base de donnée\patient sans 
 crise\chb01_01_edfm.mat')
 deriv1=(val(1,:)-0)/2.559375;
 Fs=256;
 t1=(0:length(deriv1)-1)/Fs; 
 deriv2=(val(2,:)-0)/2.559375;
 Fs=256;
 t2=(0:length(deriv2)-1)/Fs;
 deriv3=(val(3,:)-0)/2.559375;
 Fs=256;
 t3=(0:length(deriv3)-1)/Fs;
 deriv4=(val(4,:)-0)/2.559375;
 Fs=256;
 t4=(0:length(deriv4)-1)/Fs;
 deriv5=(val(5,:)-0)/2.559375;
 Fs=256;
 t5=(0:length(deriv5)-1)/Fs;
 deriv6=(val(6,:)-0)/2.559375;
 Fs=256;
 t6=(0:length(deriv6)-1)/Fs;
 deriv7=(val(7,:)-0)/2.559375;
 Fs=256;
 t7=(0:length(deriv7)-1)/Fs;
 deriv8=(val(8,:)-0)/2.559375;
 Fs=256;
 t8=(0:length(deriv8)-1)/Fs;
 deriv9=(val(9,:)-0)/2.559375;
 Fs=256;
 t9=(0:length(deriv9)-1)/Fs;
 deriv10=(val(10,:)-0)/2.559375;
 Fs=256;
 t10=(0:length(deriv10)-1)/Fs;
 deriv11=(val(11,:)-0)/2.559375;
 Fs=256;
 t11=(0:length(deriv11)-1)/Fs;
 deriv12=(val(12,:)-0)/2.559375;
 Fs=256;
 t12=(0:length(deriv12)-1)/Fs;
 deriv13=(val(13,:)-0)/2.559375;
 Fs=256;
 t13=(0:length(deriv13)-1)/Fs;
 deriv14=(val(14,:)-0)/2.559375;
 Fs=256;
 t14=(0:length(deriv14)-1)/Fs;
 deriv15=(val(15,:)-0)/2.559375;
 Fs=256;
 t15=(0:length(deriv15)-1)/Fs;
 deriv16=(val(16,:)-0)/2.559375;
 Fs=256;
 t16=(0:length(deriv16)-1)/Fs;
deriv17=(val(17,:)-0)/2.559375;
Fs=256;
t17=(0:length(deriv17)-1)/Fs;
deriv18=(val(18,:)-0)/2.559375;
Fs=256;
 t18=(0:length(deriv18)-1)/Fs;
 deriv19=(val(19,:)-0)/2.559375;
 Fs=256;
 t19=(0:length(deriv19)-1)/Fs;
 deriv20=(val(20,:)-0)/2.559375;
 Fs=256;
 t20=(0:length(deriv20)-1)/Fs;
 deriv21=(val(21,:)-0)/2.559375;
 Fs=256;
 t21=(0:length(deriv21)-1)/Fs;
 deriv22=(val(22,:)-0)/2.559375;
 Fs=256;
 t22=(0:length(deriv22)-1)/Fs;
 deriv23=(val(23,:)-0)/2.559375;
 Fs=256;
 t23=(0:length(deriv23)-1)/Fs;
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 a = filtfilt(d1,deriv1);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 b = filtfilt(d1,deriv2);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 z= filtfilt(d1, deriv3);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 d = filtfilt(d1, deriv4);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 e = filtfilt(d1, deriv5);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 f = filtfilt(d1, deriv6);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 g = filtfilt(d1, deriv7);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 h= filtfilt(d1, deriv8);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 i = filtfilt(d1,deriv9);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 j = filtfilt(d1, deriv10);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 k= filtfilt(d1, deriv11);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 ll = filtfilt(d1, deriv12);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 m = filtfilt(d1, deriv13);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 n = filtfilt(d1, deriv14);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 o = filtfilt(d1, deriv15);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 p= filtfilt(d1, deriv16);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 q = filtfilt(d1, deriv17);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 r = filtfilt(d1, deriv18);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 s = filtfilt(d1, deriv19);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 x = filtfilt(d1, deriv20);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 u = filtfilt(d1, deriv21);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 v= filtfilt(d1, deriv22);
 d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'Passb
 andRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
 w = filtfilt(d1, deriv23);

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Stephen23 2017-4-11

编辑：Stephen23 2017-4-11

Computers are actually only good at doing just one thing: repeatedly doing very simple tasks. So when you find yourself copy-and-pasting code one thousand time like that you are just doing the computer's job for it. Why waste your life doing exactly what the computer can do faster and better?

Do not replicate code like that: use loops, functions, or whatever other tools make this neater, faster, simpler, and easier to check. Save your time for doing the things that the computer cannot do (like figuring out the algorithm, and picking the colorscheme).

https://www.mathworks.com/matlabcentral/answers/228557-experts-of-matlab-how-did-you-learn-any-advice-for-beginner-intermediate-users

PS: Using lots of sequential variables is also a very bad sign, because then beginners will try to access them dynamically. DO NOT DO THIS unless you really want to write slow, buggy code:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

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Answer 1

Rik 2017-4-11

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/334714-how-to-optimize-my-matlab-code#answer_262595

在 MATLAB Online 中打开

What you are asking for is not actually optimization, but rather code compactness. Therefor, I'm going to ignore the actual optimization, as it is not my field.

You can use a for-loop to make your code look more compact.

load('C:\Users\del.dell-PC\pfe\base de donnée\patient sans crise\chb01_01_edfm.mat')
Fs=256;
result=cell(23,1);
d1=designfilt('lowpassfir','PassbandFrequency',0.45,...
    'StopbandFrequency',0.5,'PassbandRipple',3,'StopbandAttenuation',...
    60,'DesignMethod','equiripple');
for n=1:23
    deriv=(val(n,:))/2.559375;%-0 doesn't do anything
    t=(0:length(deriv)-1)/Fs;%you are not using this anywhere
    result{n} = filtfilt(d1,deriv);
end
%If you have Matlab 7.0 or later, the line below will work
[a,b,z,d,e,f,g,h,i,j,k,ll,m,n,o,p,q,r,s,x,u,v,w]=result{:};
%If it doesn't, use this line:
[a,b,z,d,e,f,g,h,i,j,k,ll,m,n,o,p,q,r,s,x,u,v,w]=deal(result{:});

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Rik 2017-4-11

编辑：Rik 2017-4-11

That is what I would do as well, but I erred on the safe side, assuming the strange order of letters had some specific meaning and were going to be used later on.

And, as Jan suggests: avoid the clear all. The code I put in my answer overwrites all variables that already exist, so clear all is not necessary. If you really want something like this, at the very least replace it with clear variables, because you are even clearing all break-points.

afef 2017-4-11

编辑：afef 2017-4-11

Ok,thank you for your help.Concerning the clear all i thought that i should write it to clear the workspace but now i understand.And about the order of letters actually i use it because i will use the decomposition using wavelt for each deriv so that's why .

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Answer 2

Jan 2017-4-11

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/334714-how-to-optimize-my-matlab-code#answer_262638

Start with omitting the brute clear all. It removes all loaded functions from the memory and reloading then from disk wastes a lot of time. Use functions instead to keep the workspace clean.

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afef 2017-5-20

编辑：afef 2017-5-20

在 MATLAB Online 中打开

Please i have this part this part in my code :

 [c,l]=wavedec(a,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea1,Ed1]=wenergy(c,l)
[c,l]=wavedec(b,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea2,Ed2]=wenergy(c,l)
[c,l]=wavedec(z,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea3,Ed3]=wenergy(c,l)
[c,l]=wavedec(d,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea4,Ed4]=wenergy(c,l)
[c,l]=wavedec(e,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea5,Ed5]=wenergy(c,l)
[c,l]=wavedec(f,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea6,Ed6]=wenergy(c,l)
[c,l]=wavedec(g,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea7,Ed7]=wenergy(c,l)
[c,l]=wavedec(h,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea8,Ed8]=wenergy(c,l)
[c,l]=wavedec(i,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea9,Ed9]=wenergy(c,l)
[c,l]=wavedec(j,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea10,Ed10]=wenergy(c,l)
[c,l]=wavedec(k,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea11,Ed11]=wenergy(c,l)
[c,l]=wavedec(ll,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea12,Ed12]=wenergy(c,l)
[c,l]=wavedec(m,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea13,Ed13]=wenergy(c,l)
[c,l]=wavedec(n,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea14,Ed14]=wenergy(c,l)
[c,l]=wavedec(o,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea15,Ed15]=wenergy(c,l)
[c,l]=wavedec(p,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea16,Ed16]=wenergy(c,l)
[c,l]=wavedec(q,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea17,Ed17]=wenergy(c,l)
[c,l]=wavedec(r,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea18,Ed18]=wenergy(c,l)
[c,l]=wavedec(s,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea19,Ed19]=wenergy(c,l)
[c,l]=wavedec(x,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea20,Ed20]=wenergy(c,l)
[c,l]=wavedec(u,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea21,Ed21]=wenergy(c,l)
[c,l]=wavedec(v,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea22,Ed22]=wenergy(c,l)
[c,l]=wavedec(w,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
cA4=appcoef(c,l,'db4',4);
[Ea23,Ed23]=wenergy(c,l)

and i tried to make it short like this :

load('C:\Users\del.dell-PC\pfe\base de donnée\patient sans crise\chb01_01_edfm.mat')
Fs=256;
result=cell(23,1);
d1=designfilt('lowpassfir','PassbandFrequency',0.45,'StopbandFrequency',0.5,'PassbandRipple',3,'StopbandAttenuation',60,'DesignMethod','equiripple');
for n=1:23
  deriv=(val(n,:))/2.559375;
  t=(0:length(deriv)-1)/Fs;
  result{n} = filtfilt(d1,deriv);
  moyenne{n}=mean(result{n},2); 
  variance{n} = std(result{n},[], 2);
  Maximale{n}= max(result{n},[],2);
  Minimale{n} =  min(result{n},[],2);
  [c,l]=wavedec(result{n},4,'db4');
  [cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
  cA4=appcoef(c,l,'db4',4);
  [Ea,Ed]=wenergy(c,l)
  [Ea, Ed] = wenergy(c,l);
energie{n}= [Ea,Ed](result{n},[],2);
end
[a,b,z,d,e,f,g,h,i,j,k,ll,m,n,o,p,q,r,s,x,u,v,w]=result{:};

But i got error message "Unbalanced or unexpected parenthesis or bracket." Can you please help me how to fix it.

Walter Roberson 2017-5-21

在 MATLAB Online 中打开

energie{n}{2}(3)

afef 2017-5-21

在 MATLAB Online 中打开

i trird it but i got this error message

"Cell contents reference from a non-cell array object."

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How to optimize my Matlab code ?

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