/* nag_opt_handle_solve_lp_ipm (e04mtc) Example Program.
 *
 * Copyright 2024 Numerical Algorithms Group.
 *
 * Mark 30.3, 2024.
 */

#include <nag.h>
#include <stdio.h>

#ifdef __cplusplus
extern "C" {
#endif
static void NAG_CALL monit(void *handle, const double rinfo[],
                           const double stats[], Nag_Comm *comm,
                           Integer *inform);
#ifdef __cplusplus
}
#endif

int main(void) {

  Integer nclin, nvar, nnza, nnzc, nnzu, exit_status, i;
  Integer idlc;
  Integer *irowa = 0, *icola = 0;
  Integer iuser[2];
  double *cvec = 0, *a = 0, *bla = 0, *bua = 0, *xl = 0, *xu = 0, *x = 0,
         *u = 0;
  double rinfo[100], stats[100];
  void *handle = 0;
  /* Nag Types */
  Nag_Comm comm;

  exit_status = 0;

  printf("nag_opt_handle_solve_lp_ipm (e04mtc) Example Program Results\n\n");
  fflush(stdout);

  /* Read the data file and allocate memory */
  scanf(" %*[^\n]"); /* Skip heading in data file */
  scanf("%" NAG_IFMT " %" NAG_IFMT " %" NAG_IFMT " %" NAG_IFMT " %*[^\n]",
        &nclin, &nvar, &nnza, &nnzc);
  /* Allocate memory */
  nnzu = 2 * nvar + 2 * nclin;
  if (!(irowa = NAG_ALLOC(nnza, Integer)) ||
      !(icola = NAG_ALLOC(nnza, Integer)) ||
      !(cvec = NAG_ALLOC(nnzc, double)) || !(a = NAG_ALLOC(nnza, double)) ||
      !(bla = NAG_ALLOC(nclin, double)) || !(bua = NAG_ALLOC(nclin, double)) ||
      !(xl = NAG_ALLOC(nvar, double)) || !(xu = NAG_ALLOC(nvar, double)) ||
      !(x = NAG_ALLOC(nvar, double)) || !(u = NAG_ALLOC(nnzu, double))) {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }
  for (i = 0; i < nvar; i++) {
    x[i] = 0.0;
  }

  /* Read objective */
  for (i = 0; i < nnzc; i++) {
    scanf("%lf", &cvec[i]);
  }
  scanf("%*[^\n]");
  /* Read constraint matrix row indices */
  for (i = 0; i < nnza; i++) {
    scanf("%" NAG_IFMT, &irowa[i]);
  }
  scanf("%*[^\n]");
  /* Read constraint matrix col indices */
  for (i = 0; i < nnza; i++) {
    scanf("%" NAG_IFMT, &icola[i]);
  }
  scanf("%*[^\n]");
  /* Read constraint matrix values */
  for (i = 0; i < nnza; i++) {
    scanf("%lf", &a[i]);
  }
  scanf("%*[^\n]");
  /* Read linear constraints lower bounds */
  for (i = 0; i < nclin; i++) {
    scanf("%lf ", &bla[i]);
  }
  scanf("%*[^\n]");
  /* Read linear constraints upper bounds */
  for (i = 0; i < nclin; i++) {
    scanf("%lf ", &bua[i]);
  }
  scanf("%*[^\n]");
  /* Read variables lower bounds */
  for (i = 0; i < nvar; i++) {
    scanf("%lf ", &xl[i]);
  }
  scanf("%*[^\n]");
  /* Read variables upper bounds */
  for (i = 0; i < nvar; i++) {
    scanf("%lf ", &xu[i]);
  }
  scanf("%*[^\n]");

  /* Create the problem handle */
  /* 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)
   * Define a linear objective */
  nag_opt_handle_set_linobj(handle, nvar, cvec, NAGERR_DEFAULT);

  /* nag_opt_handle_set_simplebounds (e04rhc)
   * Define bounds on the variables */
  nag_opt_handle_set_simplebounds(handle, nvar, xl, xu, NAGERR_DEFAULT);

  /* nag_opt_handle_set_linconstr (e04rjc)
   * Define linear constraints */
  idlc = 0;
  nag_opt_handle_set_linconstr(handle, nclin, bla, bua, nnza, irowa, icola, a,
                               &idlc, NAGERR_DEFAULT);

  /* nag_opt_handle_opt_set (e04zmc)
   * Require a high accuracy solution */
  nag_opt_handle_opt_set(handle, "LPIPM Stop Tolerance = 1.0e-10",
                         NAGERR_DEFAULT);
  /* Require printing of the solution at the end of the solve */
  nag_opt_handle_opt_set(handle, "Print Solution = Yes", NAGERR_DEFAULT);
  /* Use a constant number of centrality correctors steps */
  nag_opt_handle_opt_set(handle, "LPIPM Centrality Correctors = -6",
                         NAGERR_DEFAULT);
  /* Turn on monitoring */
  nag_opt_handle_opt_set(handle, "LPIPM Monitor Frequency = 1", NAGERR_DEFAULT);

  comm.iuser = iuser;
  iuser[0] = 1;

  /* nag_opt_handle_solve_lp_ipm (e04mtc)
   * Call LP interior point solver with the default (primal-dual) algorithm */
  printf("\n++++++++++ Use the Primal-Dual algorithm ++++++++++\n");
  fflush(stdout);
  nag_opt_handle_solve_lp_ipm(handle, nvar, x, nnzu, u, rinfo, stats, monit,
                              &comm, NAGERR_DEFAULT);

  iuser[0] = 2;
  /* Solve the same problem with the self-dual algorithm */
  printf("\n++++++++++ Use the Self-Dual algorithm ++++++++++\n");
  fflush(stdout);
  nag_opt_handle_opt_set(handle, "LPIPM Algorithm = Self-Dual", NAGERR_DEFAULT);
  nag_opt_handle_opt_set(handle, "LPIPM Stop Tolerance 2 = 1.0e-11",
                         NAGERR_DEFAULT);
  nag_opt_handle_solve_lp_ipm(handle, nvar, x, nnzu, u, rinfo, stats, monit,
                              &comm, NAGERR_DEFAULT);

END:
  NAG_FREE(cvec);
  NAG_FREE(irowa);
  NAG_FREE(icola);
  NAG_FREE(a);
  NAG_FREE(bla);
  NAG_FREE(bua);
  NAG_FREE(xl);
  NAG_FREE(xu);
  NAG_FREE(x);
  NAG_FREE(u);
  /* nag_opt_handle_free (e04rzc).
   * Destroy the problem handle and deallocate all the memory. */
  if (handle)
    nag_opt_handle_free(&handle, NAGERR_DEFAULT);

  return exit_status;
}

static void NAG_CALL monit(void *handle, const double rinfo[],
                           const double stats[], Nag_Comm *comm,
                           Integer *inform) {
  /* Monitoring function */
  double tol = 1.2e-08;

  if (!comm || !comm->iuser) {
    /* The communication structure is not correctly allocated, abort solve */
    *inform = -1;
    return;
  }
  /* If x is close to the solution, print a message */
  if (comm->iuser[0] == 1) {
    if (rinfo[4] < tol && rinfo[5] < tol && rinfo[6] < tol) {
      printf("     Iteration %" NAG_IFMT "\n", (Integer)stats[0]);
      printf("     monit() reports good approximate solution "
             "(tol =, %8.2e):\n",
             tol);
    }
  } else {
    if (rinfo[14] < tol && rinfo[15] < tol && rinfo[16] < tol) {
      printf("     Iteration %" NAG_IFMT "\n", (Integer)stats[0]);
      printf("     monit() reports good approximate solution "
             "(tol =, %8.2e):\n",
             tol);
    }
  }
  fflush(stdout);
}