Explanation of solvers.lp() output

[savio.i...@gmail.com]

Below is the output of the solvers.lp(c,A,b) example in the cvxopt webpge:

     pcost       dcost       gap    pres   dres   k/t
 0:  2.6471e+00 -7.0588e-01  2e+01  8e-01  2e+00  1e+00
 1:  3.0726e+00  2.8437e+00  1e+00  1e-01  2e-01  3e-01
 2:  2.4891e+00  2.4808e+00  1e-01  1e-02  2e-02  5e-02
 3:  2.4999e+00  2.4998e+00  1e-03  1e-04  2e-04  5e-04
 4:  2.5000e+00  2.5000e+00  1e-05  1e-06  2e-06  5e-06
 5:  2.5000e+00  2.5000e+00  1e-07  1e-08  2e-08  5e-08
Optimal solution found.

What do the column's headings (that is 'pcost', 'dcost', 'gap', 'pres', 'dres', 'k/t') mean?

Thanks in advance for explanation.

regards,
Saverio

[ruilin]

I guess, pcost means primal problem cost, d cost is dual problem cost, gap = dcost - pcost?