/* nag_dtbmv (f16pgc) Example Program.
 *
 * Copyright 2005 Numerical Algorithms Group.
 *
 * Mark 8, 2005.
 */

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagf16.h>
#include <nagx04.h>

int main(void)
{

  /* Scalars */
  double alpha;
  Integer exit_status, i, incx, j, k, kd, n, pdab, xlen;

  /* Arrays */
  double *ab=0, *x=0;
  char nag_enum_arg[40];

  /* Nag Types */
  NagError fail;
  Nag_DiagType diag;
  Nag_OrderType order;
  Nag_TransType trans;
  Nag_UploType uplo;

#ifdef NAG_COLUMN_MAJOR
#define AB_UPPER(I,J) ab[(J-1)*pdab + k + I - J - 1]
#define AB_LOWER(I,J) ab[(J-1)*pdab + I - J]
  order = Nag_ColMajor;
#else
#define AB_UPPER(I,J) ab[(I-1)*pdab + J - I]
#define AB_LOWER(I,J) ab[(I-1)*pdab + k + J - I - 1]
  order = Nag_RowMajor;
#endif

  exit_status = 0;
  INIT_FAIL(fail);
  Vprintf( "nag_dtbmv (f16pgc) Example Program Results\n\n");

  /* Skip heading in data file */
  Vscanf("%*[^\n] ");
  /* Read the problem dimension */
  Vscanf("%ld%ld%*[^\n] ", &n, &kd);
  /* Read uplo */
  Vscanf("%s%*[^\n] ", nag_enum_arg);
  /* nag_enum_name_to_value(x04nac).
   * Converts NAG enum member name to value
   */
  uplo = nag_enum_name_to_value(nag_enum_arg);
  /* Read trans */
  Vscanf("%s%*[^\n] ", nag_enum_arg);
  /* nag_enum_name_to_value(x04nac).
   * Converts NAG enum member name to value
   */
  trans = nag_enum_name_to_value(nag_enum_arg);
  /* Read diag */
  Vscanf("%s%*[^\n] ", nag_enum_arg);
  /* nag_enum_name_to_value(x04nac).
   * Converts NAG enum member name to value
   */
  diag = nag_enum_name_to_value(nag_enum_arg);
  /* Read scalar parameters */
  Vscanf("%lf%*[^\n] ", &alpha);
  /* Read increment parameters */
  Vscanf("%ld%*[^\n] ", &incx);

  pdab = kd + 1;
  xlen = MAX(1, 1 + (n - 1)*ABS(incx));

  if (n > 0)
    {

      /* Allocate memory */
      if ( !(ab = NAG_ALLOC(pdab*n, double)) ||
           !(x = NAG_ALLOC(xlen, double)) )
        {
          Vprintf("Allocation failure\n");
          exit_status = -1;
          goto END;
        }
    }
  else
    {
      Vprintf("Invalid n\n");
      exit_status = 1;
      return exit_status;
    }

  /* Read A from data file */
  k = kd + 1;
  if (uplo == Nag_Upper)
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = i; j <= MIN(i+kd,n); ++j)
            Vscanf("%lf", &AB_UPPER(i,j));
        }
      Vscanf("%*[^\n] ");
    }
  else
    {
      for (i = 1; i <= n; ++i)
        {
          for (j = MAX(1,i-kd); j <= i; ++j)
            Vscanf("%lf", &AB_LOWER(i,j));
        }
      Vscanf("%*[^\n] ");
    }

  /* Input vector x */
  for (i = 1; i <= xlen; ++i)
    Vscanf("%lf%*[^\n] ", &x[i - 1]);

  /* nag_dtbmv(f16pgc).
   * Triangular banded matrix-vector multiply.
   *
   */
  nag_dtbmv(order, uplo, trans, diag, n, kd, alpha, ab, pdab,
            x, incx, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from dtbmv.\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print output vector x */
  Vprintf("%s\n", "  x");
  for (i = 1; i <= xlen; ++i)
    {
      Vprintf("%11f\n", x[i-1]);
    }

 END:
  if (ab) NAG_FREE(ab);
  if (x) NAG_FREE(x);

  return exit_status;
}