How to Change the Exponential Scale in axis to linear scale?

Question

Behrad Ze 2022-8-12

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1778560-how-to-change-the-exponential-scale-in-axis-to-linear-scale

评论： Behrad Ze 2022-8-12

R7.csv

Dear Experts,

I have a 3D surface which is being read from a file (one example file is attached). My X and Y axis are linear. I am converting the Y axis using a formula to Exponential type. After conversion, I want to plot the the 3D surface with the modifications. When I plot the data, the Y axis is also shown in Exponential. Now, I want to change the axis in a way to be shown as linear, without changing the Exonential data (only the view of axis). Is there any way to do that? I am using this code:

csvfiles = dir('*.csv');

for file = csvfiles'

sample=readmatrix(file.name);

x=sample(1,2:end);

y=sample(2:end,1);

dataSample=sample(2:end,2:end);

L=length(y);

Dalton=double(Dalton);

for i=1: L

Dalton(i)=8.227*exp(1)+6*exp(-7.9591*exp(1)-1*y(i));

end

figure();

graph=surf(x,Dalton,dataSample);

set(graph,'LineStyle','none');

title(file.name)

colormap('turbo');

colorbar();

end

Thank You so much for your support.

Best,

Behrad

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Behrad Ze 2022-8-12

Thank You so much. this was all what I was looking for :)

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Answer 1

dpb 2022-8-12

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1778560-how-to-change-the-exponential-scale-in-axis-to-linear-scale#answer_1025770

Guessing at what you mean, precisely, try something like--

Dalton=8.227*exp(1)+6*exp(-7.9591*exp(1)*y);        % use MATLAB vector syntax, no loop needed here
hS=surf(x,Dalton,dataSample,'linestyle','none');
[du,ia]=unique(Dalton,'stable');                    % the double exponential saturates very quickly
yu=y(ia);                                           % the y values to match
ytks=yticks;                                        % retrieve default tick values y axis
ytks=ytks(iswithin(ytks,min(du),max(du)));          % save only those within range that exists
yticks(ytks)                                        % set the new subset on plot
yticklabels(interp1(du,uy,ytks))                    % label with y that produced that Dalton on tick

The double exponential saturates very quickly as can be seen

And interp1 won't work with duplicate values on the X direction for the reverse lookup; hence the unique to retrieve all values that are numerically distinguishable.

Then, to have values that will produce a result for y, must restrict the shown tick values to be within that range.

iswithin is my handy-dandy utility routine

function flg=iswithin(x,lo,hi)
% returns T for values within range of input
% SYNTAX:
%  [log] = iswithin(x,lo,hi)
%      returns T for x between lo and hi values, inclusive
  flg= (x>=lo) & (x<=hi);
end