Each problem in the CUTEr/CUTEst test set comes with a simple problem classification. This classification was inspired by the scheme of Hock and Schittkowski (Test Examples for Nonlinear Programming Codes, Lectures Notes in Economics and Mathematical Systems 187, Springer Verlag, 1981).
A problem is classified by the string
XXXr-XX-n-mThis string must not contain any blanks. In what follows, we state the admissible letters and integers, together with their interpretation, for each character in the classification string. Note that all letters must be given in upper case.
The first character in the string defines the type of the problem objective function. Possible values are:
The second character in the string defines the type of constraints of the problem. Possible values are:
The third character in the string indicates the smoothness of the problem. There are two choices:
The integer (r) which corresponds to the fourth character of the string is the degree of the highest derivatives provided analytically within the problem description. It is restricted to being one of the single characters 0, 1 or 2.
The character immediately following the first hyphen indicates the primary origin and/or interest of the problem. Possible values are:
The next character in the string indicates whether or not the problem description contains explicit internal variables. There are two possible values, namely
The symbol(s) between the second and third hyphen indicate the number of variables in the problem. Possible values are
The symbol(s) after the third hyphen indicate the number of constraints (other than fixed variables and bounds) in the problem. Note that fixed variables are not considered as general constraints here. The two possible values are