Modify an Excel sheet from Matlab

ccook picture ccook · Feb 23, 2009 · Viewed 10.7k times · Source

Is it possible to open a worksheet in excel from matlab and edit the formulas? The idea is to automate an uncertainty analysis by creating a second sheet with the uncertainty in each cell for the value from the previous cell. Essentially, I want to treat the cells as variables and do SQRT(SUM(Partials(xi)^2)) for each cell. Matlab should have no problem with the calc, but can it edit the formulas in sheets?

The process currently is to copy and paste from excel to matlab. Here's a small function that does the uncertainty in matlab against on array of equations:

function [f_u_total f_u] = uncertAnalysis(f, vars, vars_u)
    f_u = [];
    f_u_total = [];
    for(i=1:length(f))
        f(i)
        item = uncertAnalysisi(f(i), vars, vars_u);
        f_u = [f_u; item(1)];
        f_u_total = [f_u_total; item(1)];
    end
end


function [f_u_total f_u] = uncertAnalysisi(f, vars, vars_u)
    f_u = [];
    % take the partials and square them
    for i=1:length(vars)
        f_u = [f_u; vars(i) (diff(f, vars(i)).*vars_u(i)).^2];
    end
    % calculate the RSS
    f_u_total = (sum(f_u(:,2))).^.5;
end

As an aside, the equations look something like this (why I'm not doing this by hand):

=(9*C!S3^2/C!V3^4*C!W3*(C!O3-
C!P3)/C!X3*C!Q3^6*C!F3^4/C!Y3^6/(C!U3^C!Z3)^6*F3^2+1/4*C!S3^2/C!V3^4*C!W3/(C!O3-
C!P3)/C!X3*C!Q3^6*C!F3^6/C!Y3^6/(C!U3^C!Z3)^6*O3^2+1/4*C!S3^2/C!V3^4*C!W3/(C!O3-
C!P3)/C!X3*C!Q3^6*C!F3^6/C!Y3^6/(C!U3^C!Z3)^6*P3^2+9*C!S3^2/C!V3^4*C!W3*(C!O3-
C!P3)/C!X3*C!Q3^4*C!F3^6/C!Y3^6/(C!U3^C!Z3)^6*Q3^2+1/C!V3^4*C!W3*(C!O3-
C!P3)/C!X3*C!Q3^6*C!F3^6/C!Y3^6/(C!U3^C!Z3)^6*S3^2+9*C!S3^2/C!V3^4*C!W3*(C!O3-
C!P3)/C!X3*C!Q3^6*C!F3^6/C!Y3^6/(C!U3^C!Z3)^6*C!Z3^2/C!U3^2*U3^2+4*C!S3^2/C!V3^6*C!W3*(C!O
3-C!P3)/C!X3*C!Q3^6*C!F3^6/C!Y3^6/(C!U3^C!Z3)^6*V3^2+1/4*C!S3^2/C!V3^4/C!W3*(C!O3-
C!P3)/C!X3*C!Q3^6*C!F3^6/C!Y3^6/(C!U3^C!Z3)^6*W3^2+1/4*C!S3^2/C!V3^4*C!W3*(C!O3-
C!P3)/C!X3^3*C!Q3^6*C!F3^6/C!Y3^6/(C!U3^C!Z3)^6*X3^2+9*C!S3^2/C!V3^4*C!W3*(C!O3-
C!P3)/C!X3*C!Q3^6*C!F3^6/C!Y3^8/(C!U3^C!Z3)^6*Y3^2+9*C!S3^2/C!V3^4*C!W3*(C!O3-
C!P3)/C!X3*C!Q3^6*C!F3^6/C!Y3^6/(C!U3^C!Z3)^6*LOG(C!U3)^2*Z3^2)^(1/2)

Answer

Jason S picture Jason S · Feb 23, 2009

You should be able to do it through COM/ActiveX/Automation. Look at the External Interfaces document; there's an example for how to access Excel documents through Excel's Automation interfaces.

I have next-to-no experience manipulating Excel in this manner, but I know you can do just about anything in Excel through Automation and editing cell formulas doesn't sound that hard.

edit: I can't find a reference to the Excel object model, but here's another example: http://support.microsoft.com/kb/301982