[R] Interpretation of call to aov()

[JeeBee]

Or, perhaps I can use Error(subject/(method * problem))
where subject = paste(method, problem)

Because I repeated each simulation several times for
different problems of the same problem.
This gives me the following output:

> summary(aov(performance ~ method * problem + Error(subj/(method *
> problem)), data=data))

Error: subj
          Df     Sum Sq    Mean Sq F value    Pr(>F)
method        6 3.3185e+11 5.5308e+10  46.179 3.020e-13 ***
problem        1 5.7141e+11 5.7141e+11 477.094 < 2.2e-16 ***
method:problem    6 9.8891e+10 1.6482e+10  13.761 3.123e-07 ***
Residuals 28 3.3535e+10 1.1977e+09
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Error: Within
           Df     Sum Sq    Mean Sq F value Pr(>F)
Residuals 377 2.0193e+10 5.3562e+07
Warning message:
Error() model is singular in: aov(performance ~ method * problem +
Error(subj/(method * problem)), data = data)