On Wed, 6 Jun 2018, Jan van Rijn wrote:
The way I interpreted your solution was that 'at least one y-value per
column will be >= 1'.
I don't see exactly which constraint makes sure that there will be exactly
one y-value per column 1
(which, again, we don't need if all values in M are >= 0).
You are correct.
The y's have no upper bound, not even one.
If M contains negative values, it could be that:
* an ideal solution would have multiple y-values per column bigger than
zero, and
* These values will not necessarily be one, but can take even higher values
(due to this GLPK gave an error message, and this is how I found out)
In the case of negative M's,
Adding SUM y[r,c] = 1
r
is sufficient.
The y's still do not need to be declared binary.
Being an added constraint, it might speed things up with positive M's.
--
Michael henne...@web.cs.ndsu.nodak.edu
"Sorry but your password must contain an uppercase letter, a number,
a haiku, a gang sign, a heiroglyph, and the blood of a virgin."
-- someeecards
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