```/* nag_dppsvx (f07gbc) Example Program.
*
* Copyright 2017 Numerical Algorithms Group.
*
* Mark 26.2, 2017.
*/

#include <stdio.h>
#include <nag.h>
#include <nagx04.h>
#include <nag_stdlib.h>
#include <nagf07.h>

int main(void)
{

/* Scalars */
double rcond;
Integer exit_status = 0, i, j, n, nrhs, pdb, pdx;

/* Arrays */
double *afp = 0, *ap = 0, *b = 0, *berr = 0, *ferr = 0;
double *s = 0, *x = 0;
char nag_enum_arg[40];

/* Nag Types */
NagError fail;
Nag_OrderType order;
Nag_EquilibrationType equed;
Nag_UploType uplo;

#ifdef NAG_COLUMN_MAJOR
#define A_UPPER(I, J) ap[J*(J-1)/2 + I - 1]
#define A_LOWER(I, J) ap[(2*n-J)*(J-1)/2 + I - 1]
#define B(I, J)       b[(J-1)*pdb + I - 1]
order = Nag_ColMajor;
#else
#define A_LOWER(I, J) ap[I*(I-1)/2 + J - 1]
#define A_UPPER(I, J) ap[(2*n-I)*(I-1)/2 + J - 1]
#define B(I, J)       b[(I-1)*pdb + J - 1]
order = Nag_RowMajor;
#endif

INIT_FAIL(fail);

printf("nag_dppsvx (f07gbc) Example Program Results\n\n");

/* Skip heading in data file */
scanf("%*[^\n]");
scanf("%" NAG_IFMT "%" NAG_IFMT "%*[^\n]", &n, &nrhs);
if (n < 0 || nrhs < 0) {
printf("Invalid n or nrhs\n");
exit_status = 1;
goto END;
}
scanf("%39s%*[^\n]", nag_enum_arg);
/* nag_enum_name_to_value (x04nac).
* Converts NAG enum member name to value
*/
uplo = (Nag_UploType) nag_enum_name_to_value(nag_enum_arg);

#ifdef NAG_COLUMN_MAJOR
pdb = n;
pdx = n;
#else
pdb = nrhs;
pdx = nrhs;
#endif

/* Allocate memory */
if (!(afp = NAG_ALLOC(n * (n + 1) / 2, double)) ||
!(ap = NAG_ALLOC(n * (n + 1) / 2, double)) ||
!(b = NAG_ALLOC(n * nrhs, double)) ||
!(berr = NAG_ALLOC(nrhs, double)) ||
!(ferr = NAG_ALLOC(nrhs, double)) ||
!(s = NAG_ALLOC(n, double)) || !(x = NAG_ALLOC(n * nrhs, double)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

/* Read the upper or lower triangular part of the matrix A from data file */
if (uplo == Nag_Upper)
for (i = 1; i <= n; ++i)
for (j = i; j <= n; ++j)
scanf("%lf", &A_UPPER(i, j));
else if (uplo == Nag_Lower)
for (i = 1; i <= n; ++i)
for (j = 1; j <= i; ++j)
scanf("%lf", &A_LOWER(i, j));
scanf("%*[^\n]");

/* Read B from data file */
for (i = 1; i <= n; ++i)
for (j = 1; j <= nrhs; ++j)
scanf("%lf", &B(i, j));
scanf("%*[^\n]");

/* Solve the equations AX = B for X using nag_dppsvx (f07gbc). */
nag_dppsvx(order, Nag_EquilibrateAndFactor, uplo, n, nrhs, ap, afp, &equed,
s, b, pdb, x, pdx, &rcond, ferr, berr, &fail);
if (fail.code != NE_NOERROR && fail.code != NE_SINGULAR) {
printf("Error from nag_dppsvx (f07gbc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}

/* Print solution using nag_gen_real_mat_print (x04cac). */
fflush(stdout);
nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, nrhs,
x, pdx, "Solution(s)", 0, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_gen_real_mat_print (x04cac).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
/* Print error bounds, condition number and the form of equilibration */
printf("\nBackward errors (machine-dependent)\n");
for (j = 0; j < nrhs; ++j)
printf("%11.1e%s", berr[j], j % 7 == 6 ? "\n" : " ");

printf("\n\nEstimated forward error bounds (machine-dependent)\n");
for (j = 0; j < nrhs; ++j)
printf("%11.1e%s", ferr[j], j % 7 == 6 ? "\n" : " ");

printf("\n\nEstimate of reciprocal condition number\n%11.1e\n\n", rcond);

if (equed == Nag_NoEquilibration)
printf("A has not been equilibrated\n");
else if (equed == Nag_RowAndColumnEquilibration)
printf("A has been row and column scaled as diag(S)*A*diag(S)\n");
if (fail.code == NE_SINGULAR) {
printf("Error from nag_dppsvx (f07gbc).\n%s\n", fail.message);
exit_status = 1;
}

END:
NAG_FREE(afp);
NAG_FREE(ap);
NAG_FREE(b);
NAG_FREE(berr);
NAG_FREE(ferr);
NAG_FREE(s);
NAG_FREE(x);

return exit_status;
}

#undef A_UPPER
#undef A_LOWER
#undef B
```