Getting coefficient from a chebfun (chebcoeffs2-chebpoly)

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Paul Rogers 2020-5-11

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/524591-getting-coefficient-from-a-chebfun-chebcoeffs2-chebpoly

编辑： Paul Rogers 2020-5-11

I worte the following code to get an apprroximation of a compressor map:

clear
clc
close all
 
FlowMeasurements = chebpts(5,[-0.2,0.8]); % x needed by Chebishev
SpeedMeasurements = chebpts(5,[25000, 55000]);  %speeds needed by Chebyshev
 
CompressorMapMatrix =[
 
    1.5805    1.2092    1.1402    1.0234    1.0095
    1.6553    1.2840    1.2564    1.0565    1.0287
    1.9070    1.5357    1.7124    1.2518    1.1505
    2.2873    1.9160    2.4317    1.7374    1.4732
    2.4935    2.1222    2.8189    2.0728    1.7064]; % thats the datas points Chebishev needs
 
FlowVector = -0.2:0.01:0.8;
approximationResult  =  chebfun2(CompressorMapMatrix,[ -0.2 0.8 25000 55000]);
 
%% Plot chebfun not scaled
for i=1:length(SpeedMeasurements)  
figure(2)
plot(approximationResult(FlowVector, SpeedMeasurements(i)));
hold on
grid on
end