surface fitting to biopharmaceutical data -凯发k8网页登录

use the current folder browser to locate and view the folder matlab\toolbox\curvefit\curvefit.

right-click the file opioidhypnoticsynergy.txt, and select import data. the import tool appears.

alternatively, you can import the data programmatically. enter the following code to read the dose-response data from the file into the matlab workspace.

data = importdata("opioidhypnoticsynergy.txt");
opioidhypnoticsynergy = array2table(data.data, ...
    "variablenames",data.textdata);

to create response surfaces, you must select two drugs as x and y inputs, and one of the four effects as the z output. after you load the variables into your workspace, you open the curve fitter app and then select variables interactively. alternatively, you can specify the initial fit variables when using the curvefitter function.

for this example, open the curve fitter app.

curvefitter

in the curve fitter app, on the curve fitter tab, in the data section, click select data. in the select fitting data dialog box, first select the opioidhypnoticsynergy table from the x data, y data, and z data drop-down lists. then select the propofol, remifentanil, and algometry variables from the new drop-down lists.

the app creates a new response surface for the algometry data. the default fit is an interpolating surface that passes through the data points.

create a copy of the current surface fit by either:

define your own equation to fit the data. on the curve fitter tab, in the fit type section, click the arrow to open the gallery. in the gallery, click custom equation in the custom group.

in the fit options pane, select and delete the example custom equation text in the edit box.

you can use the custom equation edit box to enter matlab code to define your model. the equation that defines the model must depend on the data variables x and y and a list of fixed parameters, estimable parameters, or both.

the model from the paper is:

where c_a and c_b are the drug concentrations, and ic50a, ic50b, alpha, and n are the coefficients to be estimated.

you can define this in matlab code as:

effect = emax*(ca/ic50a   cb/ic50b   ...
    alpha*(ca/ic50a).*(cb/ic50b)).^n ./ ...
    (1   (ca/ic50a   cb/ic50b   ...
    alpha*(ca/ic50a ).*(cb/ic50b)).^n);

telling the app which variables to fit and which parameters to estimate requires rewriting the variable names ca and cb as x, and y. you must include x and y when you enter a custom equation in the edit box. assume emax = 1 because the effect output is normalized.

enter the following text in the custom equation edit box.

(x/ic50a   y/ic50b   alpha*(x/ic50a).*(y/ic50b)).^n ./ 
(1   (x/ic50a   y/ic50b   alpha*(x/ic50a).*(y/ic50b)).^n)

the curve fitter app fits a surface to the data using the custom equation model.

in the fit options pane, change some of the fit options. click advanced options to expand the section.

review the results pane. view any of these results:

display the residuals plot to check the distribution of points relative to the surface. on the curve fitter tab, in the visualization section, click residuals plot.

generate code for the currently selected fit and its open plots in your curve fitter app session. on the curve fitter tab, in the export section, click export and select generate code.

the curve fitter app generates code from your session and displays the file in the matlab editor. the file includes the fit selected in your current session and its open plots.

save the file with the default name, createfit.m.

you can recreate your fit and its plots by calling the file from the command line with your original data or new data as input arguments.

in this case, because your original data still appears in the workspace, you can run the function with the original data variables.

[fitresult,gof] = createfit(opioidhypnoticsynergy.propofol, ...
    opioidhypnoticsynergy.remifentanil, ...
    opioidhypnoticsynergy.algometry)

the function creates a figure window for the fit you selected in your session. the custom fit figure shows both the surface and residuals plots that you created interactively in the curve fitter app.

create a new fit to the tetany response instead of algometry.

[fitresult,gof] = createfit(opioidhypnoticsynergy.propofol, ...
    opioidhypnoticsynergy.remifentanil, ...
    opioidhypnoticsynergy.tetany)

you need to edit the file if you want the new response label on the plots. you can use the generated code as a starting point to change the surface fits and plots to meet your needs. for a list of methods you can use, see .