how to load and calculate data from a file?

Question

P 2011-4-16

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/5619-how-to-load-and-calculate-data-from-a-file

Hi I really need help.I have this file udk.txt with 21 values. I've loaded the values from it and i need to calculate idk for each value given in the txt. This is my attempt:

*clear all;
Is=1E-9;
k = 1.38*10^(-23);
q = 1.602*10^(-19);
T = 300;
VT = k*T/q;
m = 1.5;
x=load('F:\udk.txt');
for i = 1:21
      idk=Is*(exp(x(i)/(m*VT))-1);
  end

So, how can I calculate 21 values for idk if in txt file are 21 values for udk?

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Answer 1

Matt Tearle 2011-4-16

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If x is a vector of 21 values (and all the other values are scalars), then all you need to do is

idk=Is*(exp(x/(m*VT))-1);

(Your loop would also work, but is unnecessary.) So given that you're asking, I'm guessing that this isn't working. So, what's going wrong? Do you get an error message? If so, what? What is the size of x (do >> whos x and report the output)? If x is not 1-by-21 or 21-by-1, then the problem is in the load command. In which case, please show the contents of udk.txt. Reading a text file with load requires that the formatting of the file is very simple.

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P 2011-4-16

udk.txt contains:0.000E+00

-1.000E+01

-9.999E+00

5.427E-04

5.499E-04

5.495E-04

And my program only calculate one value for idk, an i want 21 values for each udk. thx a lot for your time and i hope that you can help me

Oleg Komarov 2011-4-16

Did you try Matt's solution at all?

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Answer 2

Andrei Bobrov 2011-4-16

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https://ww2.mathworks.cn/matlabcentral/answers/5619-how-to-load-and-calculate-data-from-a-file#answer_7883

在 MATLAB Online 中打开

variant

Is=1E-9;
k = 1.38*10^(-23);
q = 1.602*10^(-19);
T = 300;
VT = k*T/q;
m = 1.5;
x=cell2mat(textscan(fopen('txt_for_P.txt'),'%f'));
idk=Is*(exp(x/(m*VT))-1);