《MATLAB数值计算案例分析》程序源代码.zip

function myfit = createFit(x,yy) %CREATEFIT Create plot of data sets and fits % CREATEFIT(X,YY) % Creates a plot, similar to the plot in the main Curve Fitting Tool, % using the data that you provide as input. You can % use this function with the same data you used with CFTOOL % or with different data. You may want to edit the function to % customize the code and this help message. % % Number of data sets: 1 % Number of fits: 1 % Data from data set "yy vs. x": % X = x: % Y = yy: % Unweighted % Auto-generated by MATLAB on 17-Dec-2010 21:03:21 % Set up figure to receive data sets and fits f_ = clf; figure(f_); set(f_,'Units','Pixels','Position',[494 176 680 491]); % Line handles and text for the legend. legh_ = []; legt_ = {}; % Limits of the x-axis. xlim_ = [Inf -Inf]; % Axes for the plot. ax_ = axes; set(ax_,'Units','normalized','OuterPosition',[0 0 1 1]); set(ax_,'Box','on'); axes(ax_); hold on; % --- Plot data that was originally in data set "yy vs. x" x = x(:); yy = yy(:); h_ = line(x,yy,'Parent',ax_,'Color',[0.333333 0 0.666667],... 'LineStyle','none', 'LineWidth',1,... 'Marker','.', 'MarkerSize',12); xlim_(1) = min(xlim_(1),min(x)); xlim_(2) = max(xlim_(2),max(x)); legh_(end+1) = h_; legt_{end+1} = 'yy vs. x'; % Nudge axis limits beyond data limits if all(isfinite(xlim_)) xlim_ = xlim_ + [-1 1] * 0.01 * diff(xlim_); set(ax_,'XLim',xlim_) else set(ax_, 'XLim',[-2.04, 2.04]); end % --- Create fit "fit 1" ok_ = isfinite(x) & isfinite(yy); if ~all( ok_ ) warning( 'GenerateMFile:IgnoringNansAndInfs',... 'Ignoring NaNs and Infs in data.' ); end st_ = [0.94699999999999995 0.38500000000000001 0.83899999999999997 ]; ft_ = fittype('a*b.^x+c*x.^2',... 'dependent',{'y'},'independent',{'x'},... 'coefficients',{'a', 'b', 'c'}); % Fit this model using new data cf_ = fit(x(ok_),yy(ok_),ft_,'Startpoint',st_); % Alternatively uncomment the following lines to use coefficients from the % original fit. You can use this choice to plot the original fit against new % data. % cv_ = { 9.9504541371165054, 3.9930448940959291, 3.1481581887763213}; % cf_ = cfit(ft_,cv_{:}); % Plot this fit h_ = plot(cf_,'fit',0.95); set(h_(1),'Color',[1 0 0],... 'LineStyle','-', 'LineWidth',2,... 'Marker','none', 'MarkerSize',6); % Turn off legend created by plot method. legend off; % Store line handle and fit name for legend. legh_(end+1) = h_(1); legt_{end+1} = 'fit 1'; % --- Finished fitting and plotting data. Clean up. hold off; % Display legend leginfo_ = {'Orientation', 'vertical', 'Location', 'NorthEast'}; h_ = legend(ax_,legh_,legt_,leginfo_{:}); set(h_,'Interpreter','none'); % Remove labels from x- and y-axes. xlabel(ax_,''); ylabel(ax_,''); myfit = cf_ % 这个句子是作者添加的用于输出拟合后的结构