Only the last value are being stored in for loop

Question

Joy Shen 2023-4-6

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1942674-only-the-last-value-are-being-stored-in-for-loop

编辑： VBBV 2023-4-10

Hi all,

I just need to have a and c store array of numbers rather than store the last number. I need to sample from [a,c] and a should be something like [0 0.5 1 1.5...] and c should be [0.5 1 1.5 2...] but as of right now a and c just take the last values, 5 and 20.

Nsim = 10000;
IBinEdges=[0:0.5:5 20]; %ft
IBinEdges_Lo=IBinEdges(1:end-1);
IBinEdges_Hi=IBinEdges(2:end);
IBinEdges_Md=IBinEdges_Lo+(diff(IBinEdges)/2);
%This is external flood (nominal) elevation
ExtSurgeBinEdges = [0:0.5:5 20];
ExtSurgeBinEdges_Lo=ExtSurgeBinEdges(1:end-1);
ExtSurgeBinEdges_Hi=ExtSurgeBinEdges(2:end);
ExtSurgeBinEdges_Md=ExtSurgeBinEdges_Lo+(diff(ExtSurgeBinEdges)/2);
% Generation every combination of external flood height and seal state
% iterations
IndF=[1:length(ExtSurgeBinEdges_Md)]';
IndA=[1:length(DamState)]';
temp1=[]; temp2=[]; [temp1,temp2]=ndgrid(IndF,IndA);
IndMatFA=[temp1(:),temp2(:)]; 
% col1: surge height
% col2: seal condition
% This is where the issue is, a and c needs to contain each bin edge for
% ExtSurgeBinEdges low and high. it just has the extremes
% Use MC simulation to generate CPT for IF node
for iComb=1:size(IndMatFA,1)  % loop over combinations of damage state and external flood height
    % Define distribution of external flood height within bin and sim:
    a=[]; a=ExtSurgeBinEdges_Lo(IndMatFA(iComb,1));
    b=[]; b=ExtSurgeBinEdges_Md(IndMatFA(iComb,1));
    c=[]; c=ExtSurgeBinEdges_Hi(IndMatFA(iComb,1));
    pd1=[]; pd1=makedist('Uniform',a,c);
    Fsim=[]; Fsim=random(pd1,[Nsim,1]); %simulate external flood heights within bin (Uniform)
    Fsim=Fsim.*(Fsim>=0); % make sure the difference is never below zero
end 

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VBBV 2023-4-10

编辑：VBBV 2023-4-10

在 MATLAB Online 中打开

Isnt this supposed to be outside of loop ?

% iComb=1:size(IndMatFA,1);
   a=[];
   b=[];
   c=[];
   pd1=[];
   Fsim=[];

Can you tell which difference is never below zero ? Do you mean successive Fsim values generated using uniform distribution ?

% which Difference is never below zero ? this line is confusing
Fsim=Fsim.*(Fsim>=0); % make sure the difference is never below zero

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Answer 1

VBBV 2023-4-6

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1942674-only-the-last-value-are-being-stored-in-for-loop#answer_1210804

编辑：VBBV 2023-4-6

在 MATLAB Online 中打开

a(iComb)=ExtSurgeBinEdges_Lo(IndMatFA(iComb,1));
  b=[]; % put this line outside of loop 
b(iComb)=ExtSurgeBinEdges_Md(IndMatFA(iComb,1));
  c=[]; % this too 
c(iComb)=ExtSurgeBinEdges_Hi(IndMatFA(iComb,1));

3 个评论
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Joy Shen 2023-4-10

在 MATLAB Online 中打开

@VBBV I did that and I see that it fixed my issue with saving the values for a and c, but the pd1 makedist isn't registering it and still show up as the original single values. Here's my new code. I defined iComb and moved a, b and c outside of the loop. In pd1 I'm tyring to index a and c by putting a(iComb) and c(iComb) but when I check pd1 it says a and c are still single values. I commented %*** where I made changes.

Basically, Fsim is not sampling from each bin I'm trying to define between the arrays of a and c.

Nsim = 10000;
IBinEdges=[0:0.5:5 20]; %ft
IBinEdges_Lo=IBinEdges(1:end-1);
IBinEdges_Hi=IBinEdges(2:end);
IBinEdges_Md=IBinEdges_Lo+(diff(IBinEdges)/2);
%This is external flood (nominal) elevation
ExtSurgeBinEdges = [0:0.5:5 20];
ExtSurgeBinEdges_Lo=ExtSurgeBinEdges(1:end-1);
ExtSurgeBinEdges_Hi=ExtSurgeBinEdges(2:end);
ExtSurgeBinEdges_Md=ExtSurgeBinEdges_Lo+(diff(ExtSurgeBinEdges)/2);
% Generation every combination of external flood height and seal state
% iterations
IndF=[1:length(ExtSurgeBinEdges_Md)]';
IndA=[1:length(DamState)]';
temp1=[]; temp2=[]; [temp1,temp2]=ndgrid(IndF,IndA);
IndMatFA=[temp1(:),temp2(:)]; 
% col1: surge height
% col2: seal condition
% This is where the issue is, a and c needs to contain each bin edge for
% ExtSurgeBinEdges low and high. it just has the extremes
% Use MC simulation to generate CPT for IF node
%***
iComb=1:size(IndMatFA,1);
    a=[]; a=ExtSurgeBinEdges_Lo(IndMatFA(iComb,1));
    b=[]; b=ExtSurgeBinEdges_Md(IndMatFA(iComb,1));
    c=[]; c=ExtSurgeBinEdges_Hi(IndMatFA(iComb,1));
    
for iComb=1:size(IndMatFA,1)  % loop over combinations of damage state and external flood height
    % Define distribution of external flood height within bin and sim:
    pd1=[]; pd1=makedist('Uniform',a(iComb),c(iComb)); %***
    Fsim=[]; Fsim=random(pd1,[Nsim,1]); %simulate external flood heights within each bin (Uniform)
    Fsim=Fsim.*(Fsim>=0); % make sure the difference is never below zero
end 

VBBV 2023-4-10

编辑：VBBV 2023-4-10

在 MATLAB Online 中打开

Nsim = 10000;
IBinEdges=[0:0.5:5 20]; %ft
IBinEdges_Lo=IBinEdges(1:end-1);
IBinEdges_Hi=IBinEdges(2:end);
IBinEdges_Md=IBinEdges_Lo+(diff(IBinEdges)/2);
%This is external flood (nominal) elevation
ExtSurgeBinEdges = [0:0.5:5 20];
ExtSurgeBinEdges_Lo=ExtSurgeBinEdges(1:end-1);
ExtSurgeBinEdges_Hi=ExtSurgeBinEdges(2:end);
ExtSurgeBinEdges_Md=ExtSurgeBinEdges_Lo+(diff(ExtSurgeBinEdges)/2);
% Generation every combination of external flood height and seal state
% iterations
IndF=[1:length(ExtSurgeBinEdges_Md)]';
IndA=[1:length(DamState)]';
temp1=[]; temp2=[]; [temp1,temp2]=ndgrid(IndF,IndA);
IndMatFA=[temp1(:),temp2(:)]; 
% col1: surge height
% col2: seal condition
% This is where the issue is, a and c needs to contain each bin edge for
% ExtSurgeBinEdges low and high. it just has the extremes
% Use MC simulation to generate CPT for IF node
% isnt this supposed to be as in a loop ??
% iComb=1:size(IndMatFA,1);
   a=[];
   b=[];
   c=[];
   pd1=[];
   Fsim=[];
   
   
for iComb=1:size(IndMatFA,1)  
    % loop over combinations of damage state and external flood height
    % Define distribution of external flood height within bin and sim:
    a(iComb)=ExtSurgeBinEdges_Lo(IndMatFA(iComb,1));
    b(iComb)=ExtSurgeBinEdges_Md(IndMatFA(iComb,1));
    c(iComb)=ExtSurgeBinEdges_Hi(IndMatFA(iComb,1));
    
    
    pd1=makedist('Uniform','Lower',a(iComb),'Upper',c(iComb)); %***
    
    Fsim(:,iComb)=random(pd1,[Nsim,1]); %simulate external flood heights within each bin (Uniform)   
end 
 % check if the difference is never below zero
 Fsim=Fsim.*(Fsim>=0); % make sure the difference is never below zero