Borderbasix

The optimization solvers of borderbasix

The tool solver_opt computes the goblal minimun and the minimizers of a polynomial function in a basic semialgebraic set, when there is a finite number of minimizers.

\[ inf f(x) s.t​. g_1(x)=0,\ldots,g_{n_1}(x)=0,h_1(x)\ge 0,\ldots,h_{n_2}(x)\ge 0 \]

It can be used as follows:

solver_opt expl

where expl is a file containing the data of the minimization problem. The structure of the data file is the following:

1 n1 n2
f;
g_i;
...
h_j;
...

where

Here is an example with one polynomial function to optimize under zero equality constraint and 3 non-negativity constraints:

1 0 3
-10+2*x0+6*x1-2*x0^2+2*x0*x1-2*x1^2;
-x0^2+2*x0;
-8-x1^2+6*x1;
1-x0^2+2*x0*x1-x1^2;

The polynomials are separated by a ; The variables are x0, x1, … The output result is the dimension of the quotient space:

Number of solution(s): 1
Infimum: -3.0000000000

The infimum and an approximation of the minimizer(s) are stored in the file expl.sol:

sol:= [[0.1625682092242973109e1,0.2233710195183024716e1]];
fmin:= -0.3e1;

Options:

--help, -h : print this message
-s n : solver that you can use (1-SDPA, 2-SDPAGMP, 3-CSDP, 4-MOSEK)
(1 by default)
-m n : use the method decomposer (0) or the full matrix method (1)
(0 by default)
-p f : use the file f as parameter file in the sdpa call
-t threshold : precise the threshold (1e-3 by default)
-b n : precise if we use the complet border basis (0 by default) or not (1)
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