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The MOSEK command line tool Version 7.0 (Revision 141)

The MOSEK command line tool. Version 7.0 ... - Documentation

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8.5. SENSITIVITY ANALYSIS WITH THE COMMAND LINE TOOL 75<br />

<strong>The</strong> <strong>line</strong>arity intervals and shadow prices for u c i , lx j , and ux j are computed similarly to lc i .<br />

<strong>The</strong> left and right shadow prices for c j denoted σ 1 and σ 2 respectively are computed as follows:<br />

and<br />

σ 1 = minimize e T j x<br />

subject to l c + βe i ≤ Ax ≤ u c ,<br />

c T x = z ∗ ,<br />

l x ≤ x ≤ u x<br />

σ 2 = maximize e T j x<br />

subject to l c + βe i ≤ Ax ≤ u c ,<br />

c T x = z ∗ ,<br />

l x ≤ x ≤ u x .<br />

Once again the above two optimization problems make it easy to interpret the shadow prices. Indeed,<br />

if x ∗ is an arbitrary primal optimal solution, then<br />

x ∗ j ∈ [σ 1 , σ 2 ].<br />

<strong>The</strong> <strong>line</strong>arity interval [β 1 , β 2 ] for a c j is computed as follows:<br />

and<br />

β 1 = minimize β<br />

subject to A T (s c l − s c u) + s x l − s x u = c + βe j ,<br />

(l c ) T (s c l ) − (u c ) T (s c u) + (l x ) T (s x l ) − (u x ) T (s x u) − σ 1 β ≤ z ∗ ,<br />

s c l , s c u, s c l , s x u ≥ 0<br />

β 2 = maximize β<br />

subject to A T (s c l − s c u) + s x l − s x u = c + βe j ,<br />

(l c ) T (s c l ) − (u c ) T (s c u) + (l x ) T (s x l ) − (u x ) T (s x u) − σ 2 β ≤ z ∗ ,<br />

s c l , s c u, s c l , s x u ≥ 0.<br />

8.5 Sensitivity analysis with the <strong>command</strong> <strong>line</strong> <strong>tool</strong><br />

A sensitivity analysis can be performed with the <strong>MOSEK</strong> <strong>command</strong> <strong>line</strong> <strong>tool</strong> using the <strong>command</strong><br />

mosek myproblem.mps -sen sensitivity.ssp<br />

where sensitivity.ssp is a file in the format described in the next section. <strong>The</strong> ssp file describes<br />

which parts of the problem the sensitivity analysis should be performed on.<br />

By default results are written to a file named myproblem.sen.<br />

changed by setting the<br />

MSK SPAR SENSITIVITY RES FILE NAME<br />

If necessary, this filename can be

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