/* nag_opt_sdp_read_sdpa (e04rdc) Example Program.
*
* Copyright 2024 Numerical Algorithms Group.
*
* Mark 30.0, 2024.
*/
/* Load a linear semidefinite programming problem from a sparse SDPA
* file, formulate the problem via a handle, pass it to the solver
* and print both primal and dual variables.
*/
#include <nag.h>
#include <stdio.h>
int main(int argc, char *argv[]) {
char fname_default[] = "e04rdce.opt";
Integer filelst = 0;
Integer exit_status = 0;
Integer dima, idblk, idx, inform, j, k, maxnblk, maxnnz, maxnvar, nblk, nnz,
nnzu, nnzuc, nnzua, nvar;
char *fname = 0;
char title[60];
double rinfo[32], stats[32];
double *a = 0, *cvec = 0, *ua = 0, *x = 0;
Integer *blksizea = 0, *icola = 0, *irowa = 0, *nnza = 0;
void *handle = 0;
/* Nag Types */
Nag_FileID infile;
NagError fail;
printf("nag_opt_sdp_read_sdpa (e04rdc) Example Program Results\n\n");
/* Use the first command line argument as the filename or
* choose default filename stored in 'fname_default'. */
if (argc > 1)
fname = argv[1];
else
fname = fname_default;
printf("Reading SDPA file: %s\n", fname);
fflush(stdout);
/* nag_file_open (x04acc).
* Open unit number for reading and associate unit with named file. */
nag_file_open(fname, 0, &infile, NAGERR_DEFAULT);
/* Go through the file for the first time to find the dimension
* of the problem. Unless the file format is wrong, the function
* should finish with fail.code = NE_INT_MAX (not enough space). */
/* nag_opt_sdp_read_sdpa (e04rdc).
* A reader of sparse SDPA data files for linear SDP problems. */
INIT_FAIL(fail);
nag_opt_sdp_read_sdpa(infile, 0, 0, 0, filelst, &nvar, &nblk, &nnz, NULL,
NULL, NULL, NULL, NULL, NULL, &fail);
/* nag_file_close (x04adc).
* Close file associated with given unit number. */
nag_file_close(infile, NAGERR_DEFAULT);
if (fail.code != NE_INT_MAX) {
/* Possible problem with formatting, etc. Stop. */
printf("Error from nag_opt_sdp_read_sdpa (e04rdc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
/* Allocate the right size of arrays for the data. */
printf("Allocating space for the problem.\n");
printf("nvar = %" NAG_IFMT "\n", nvar);
printf("nblk = %" NAG_IFMT "\n", nblk);
printf("nnz = %" NAG_IFMT "\n", nnz);
fflush(stdout);
maxnvar = nvar;
maxnblk = nblk;
maxnnz = nnz;
if (!(cvec = NAG_ALLOC(maxnvar, double)) ||
!(nnza = NAG_ALLOC(maxnvar + 1, Integer)) ||
!(irowa = NAG_ALLOC(maxnnz, Integer)) ||
!(icola = NAG_ALLOC(maxnnz, Integer)) ||
!(a = NAG_ALLOC(maxnnz, double)) ||
!(blksizea = NAG_ALLOC(maxnblk, Integer))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
/* Reopen the same file. */
nag_file_open(fname, 0, &infile, NAGERR_DEFAULT);
/* Read the problem data, there should be enough space this time.
* nag_opt_sdp_read_sdpa (e04rdc).
* A reader of sparse SDPA data files for linear SDP problems. */
nag_opt_sdp_read_sdpa(infile, maxnvar, maxnblk, maxnnz, filelst, &nvar, &nblk,
&nnz, cvec, nnza, irowa, icola, a, blksizea,
NAGERR_DEFAULT);
/* nag_file_close (x04adc).
* Close file associated with given unit number. */
nag_file_close(infile, NAGERR_DEFAULT);
/* Problem was successfully decoded. */
printf("Linear SDP problem was read, start formulating the problem\n");
fflush(stdout);
/* nag_opt_handle_init (e04rac).
* Initialize an empty problem handle with nvar variables. */
nag_opt_handle_init(&handle, nvar, NAGERR_DEFAULT);
/* nag_opt_handle_set_linobj (e04rec).
* Add a linear objective function to the formulation. */
nag_opt_handle_set_linobj(handle, nvar, cvec, NAGERR_DEFAULT);
dima = 0;
for (k = 0; k < nblk; k++)
dima += blksizea[k];
idblk = 0;
/* nag_opt_handle_set_linmatineq (e04rnc).
* Add all linear matrix constraints to the formulation.*/
nag_opt_handle_set_linmatineq(handle, nvar, dima, nnza, nnz, irowa, icola, a,
nblk, blksizea, &idblk, NAGERR_DEFAULT);
printf("The problem formulation in a handle is completed.\n\n");
fflush(stdout);
/* nag_opt_handle_print (e04ryc).
* Print overview of the handle. */
nag_opt_handle_print(handle, 6, "Overview", NAGERR_DEFAULT);
/* Set optional arguments of the solver by calling
* nag_opt_handle_opt_set (e04zmc). */
nag_opt_handle_opt_set(handle, "DIMACS Measures = Check", NAGERR_DEFAULT);
nag_opt_handle_opt_set(handle, "Initial X = Automatic", NAGERR_DEFAULT);
/* Compute memory needed for primal & dual variables. */
/* There are no box constraints or linear constraints set
* by e04rhc or by e04rjc, neither second order cone constraints.*/
nnzu = 0;
nnzuc = 0;
/* Count size of the matrix multipliers, they are stored as packed
* triangles respecting the block structure. */
nnzua = 0;
for (k = 0; k < nblk; k++)
nnzua += blksizea[k] * (blksizea[k] + 1) / 2;
if (!(x = NAG_ALLOC(nvar, double)) || !(ua = NAG_ALLOC(nnzua, double))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
/* Call the solver nag_opt_handle_solve_pennon (e04svc). */
INIT_FAIL(fail);
nag_opt_handle_solve_pennon(handle, nvar, x, nnzu, NULL, nnzuc, NULL, nnzua,
ua, rinfo, stats, &inform, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_opt_handle_solve_pennon (e04svc).\n%s\n",
fail.message);
exit_status = 2;
goto END;
}
/* Print results. */
printf("\nOptimal solution x:\n");
for (j = 0; j < nvar; j++)
printf(" %f\n", x[j]);
fflush(stdout);
/* Print packed lower triangles of the Lagrangian multipliers. */
idx = 0;
for (k = 0; k < nblk; k++) {
sprintf(title, "Lagrangian multiplier for A_%" NAG_IFMT, k);
nnz = blksizea[k] * (blksizea[k] + 1) / 2;
/* nag_file_print_matrix_real_packed (x04ccc).
* Print real packed triangular matrix. */
nag_file_print_matrix_real_packed(Nag_ColMajor, Nag_Lower, Nag_NonUnitDiag,
blksizea[k], ua + idx, title, NULL,
NAGERR_DEFAULT);
idx = idx + nnz;
}
END:
/* nag_opt_handle_free (e04rzc).
* Destroy the problem handle and deallocate all the memory. */
if (handle)
nag_opt_handle_free(&handle, NAGERR_DEFAULT);
NAG_FREE(a);
NAG_FREE(cvec);
NAG_FREE(ua);
NAG_FREE(x);
NAG_FREE(blksizea);
NAG_FREE(icola);
NAG_FREE(irowa);
NAG_FREE(nnza);
return exit_status;
}