Make polyfit instead of plot

Question

rockstar49 2022-9-2

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1793700-make-polyfit-instead-of-plot

回答： Walter Roberson 2022-9-2

Hi,

id like to make this into a polyfit instead of a plot.

% Plotting of FRF
fig = figure(1000+p);p=p+1;
set(fig, 'WindowStyle', 'docked');
set(gcf,'color','w');
subplot(3,1,1);
if HOLD
    hold on;
end
plot(f,abs(FRF), color, 'linewidth', 2);
ylim([0 1.5]);
xlim([0,f_range]);
grid on;box on;
ylabel('Speed/Speed*');

4 个评论
显示 2更早的评论隐藏 2更早的评论

dpb 2022-9-2

What in the world is FRF??? Does the plot bear any relationship to a polynomial of some degree?

With zero useful information, pretty-much at a loss here...

Star Strider 2022-9-2

@Zakir Mahmood — What result do you want?

@dpb — Probably: Frequency Response Function.

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Answer 1

Walter Roberson 2022-9-2

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1793700-make-polyfit-instead-of-plot#answer_1040895

在 MATLAB Online 中打开

polynomial_degree = 3;  %adjust as appropriate
p = polyfit(f, abs(FRF), polynomial_degree);
fig = figure(1000+p);p=p+1;
set(fig, 'WindowStyle', 'docked');
set(gcf,'color','w');
subplot(3,1,1);
if HOLD
    hold on;
end
plot(f,abs(FRF), color, 'linewidth', 2, 'DisplayName', 'abs(FRF)');
y = polyval(p, f);
oldhold = hold('on');
plot(f, y, 'b', 'Linewidth', 2, 'DisplayName', 'fitted abs(FRF)');
hold(oldhold)
ylim([0 1.5]);
xlim([0,f_range]);
grid on;box on;
ylabel('Speed/Speed*');
legend show