[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Bug-glpk] min{} over empty set; result undefined
From: |
xypron |
Subject: |
[Bug-glpk] min{} over empty set; result undefined |
Date: |
Thu, 18 Dec 2008 12:09:52 -0800 (PST) |
Hello Andrew,
I received the error
min{} over empty set; result undefined
for the following statement.
param ti{i in O} := max( ti0[i] , min( ta0[i], min{(i,j) in V diff I }
ti0[j]) - d[i] );
Currently for operations over sets in GLPK the following definitions have
been made:
prod{i in {}} i = 1;
sum{i in {}} = 0;
because 1 and 0 are the neutral elements for the operations * and +.
It would be useful to add by definition:
max{i in {}} i = -DBL_MAX; # -infinity
min{i in {}} i = DBL_MAX; # infinity
because -infinity and infinity are the neutral elements for the operations
max and min.
This can save using "if" expressions in cases as the one above.
Best regards
Xypron
--
View this message in context:
http://www.nabble.com/min%7B%7D-over-empty-set--result-undefined-tp21080007p21080007.html
Sent from the Gnu - GLPK - Bugs mailing list archive at Nabble.com.
- [Bug-glpk] min{} over empty set; result undefined,
xypron <=