problem.getcols
problem.getcols |
Purpose
Returns the nonzeros in the constraint matrix for the columns in a given range.
Synopsis
problem.getcols (mstart, mrwind, dmatval, size, first, last)
Arguments
|
mstart
|
Array which will be filled with the indices indicating the starting offsets in the
mrwind and
dmatval arrays for each requested column. It must be of length at least
last-first+2. Column
i starts at position
mstart[i] in the
mrwind and
dmatval arrays, and has
mstart[i+1]-mstart[i] elements in it. May be
None if not required, but must be specified.
|
|
mrwind
|
Array of length
size which will be filled with the rows of the nonzero coefficents for each column. May be
None if not required, but must be specified.
|
|
dmatval
|
Array of length
size which will be filled with the nonzero coefficient values. May be
None if not required, but must be specified.
|
|
size
|
The size of the
mrwind and
dmatval arrays. This is the maximum number of nonzero coefficients that the Optimizer is allowed to return.
|
|
first
|
First column in the range.
|
|
last
|
Last column in the range.
|
Example
The following examples retrieves the
mstart vector of the problem:
p = xpress.problem()
p.read("example", "l")
mstart = []
p.getcols(mstart, mrwind=None, dmatval=None, size=100, first=0, last=p.attributes.cols - 1)
Further information
It is possible to obtain just the number of elements in the range of columns by replacing
mstart,
mrwind and
dmatval by
None, as in the example. In this case,
size must be set to
0 to indicate that the length of arrays passed is zero. This is demonstrated in the example above.
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