NAG Library Manual, Mark 30.2
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NAG CL Interface Introduction
Example description
/* nag_wav_dim1_mxolap_multi_fwd (c09dcc) Example Program.
 *
 * Copyright 2024 Numerical Algorithms Group.
 *
 * Mark 30.2, 2024.
 */
/* Pre-processor includes */
#include <math.h>
#include <nag.h>
#include <stdio.h>
#include <string.h>

int main(void) {
  /* Constants */
  Integer licomm = 100;
  /*Integer scalar and array declarations */
  Integer exit_status = 0;
  Integer i, n, na, nf, nwc, nwcmax, nwlmax, nwl, nwlinv;
  Integer *icomm = 0;
  NagError fail;
  Nag_Wavelet wavnamenum;
  Nag_WaveletCoefficients keepnum;
  Nag_WaveletMode modenum;
  /*Double scalar and array declarations */
  double *c = 0, *x = 0, *y = 0;
  /*Character scalar and array declarations */
  char keep[15], mode[24], wavnam[20];

  INIT_FAIL(fail);

  printf("nag_wav_dim1_mxolap_multi_fwd (c09dcc) Example Program Results\n\n");
  fflush(stdout);

  /*     Skip heading in data file */
  scanf("%*[^\n] ");
  /*     Read n - length of input data sequence */
  scanf("%" NAG_IFMT "%*[^\n] ", &n);
  if (!(x = NAG_ALLOC(n, double)) || !(y = NAG_ALLOC(n, double)) ||
      !(icomm = NAG_ALLOC(licomm, Integer))) {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }
  /*     Read Wavelet name (wavnam) and end mode (mode) */
  scanf("%19s%23s%14s%*[^\n] ", wavnam, mode, keep);
  /*
   * nag_enum_name_to_value (x04nac).
   * Converts NAG enum member name to value
   */
  wavnamenum = (Nag_Wavelet)nag_enum_name_to_value(wavnam);
  modenum = (Nag_WaveletMode)nag_enum_name_to_value(mode);
  keepnum = (Nag_WaveletCoefficients)nag_enum_name_to_value(keep);
  if (n >= 2) {
    printf("MLMODWT :: \n");
    printf("     Wavelet            :%16s\n", wavnam);
    printf("     End mode           :%16s\n", mode);
    printf("     Store coefficients :%16s\n", keep);
    printf("     N                  :%16" NAG_IFMT "\n\n", n);
    /*        Read data array and write it out */
    printf("%s\n", " Input Data      X :");
    for (i = 0; i < n; i++) {
      scanf("%lf", &x[i]);
      printf("%8.4f%s", x[i], (i + 1) % 8 ? " " : "\n");
    }
    printf("\n");
    /*
     * nag_wav_dim1_init (c09aac)
     * Wavelet filter query
     */
    nag_wav_dim1_init(wavnamenum, Nag_MODWTMulti, modenum, n, &nwlmax, &nf,
                      &nwcmax, icomm, &fail);
    if (fail.code != NE_NOERROR) {
      printf("Error from nag_wav_dim1_init (c09aac).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
    /* Choose to decompose over two levels */
    nwl = 2;
    /* Set size of array c according to number of coefficients stored */
    if (keepnum == Nag_StoreFinal)
      nwc = nwcmax - (nwlmax - nwl) * n;
    else
      nwc = nwcmax + (nwlmax - 1) * n - (nwlmax - nwl) * 2 * n;

    if (!(c = NAG_ALLOC(nwc, double))) {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }
    /*        Perform Maximal Overlap Discrete Wavelet transform */
    /*
     * nag_wav_dim1_mxolap_multi_fwd (c09dcc)
     * one-dimensional multi-level maximal overlap discrete wavelet
     * transform (mlmodwt)
     */
    nag_wav_dim1_mxolap_multi_fwd(n, x, keepnum, nwc, c, nwl, &na, icomm,
                                  &fail);
    if (fail.code != NE_NOERROR) {
      printf("Error from nag_wav_dim1_mxolap_multi_fwd (c09dcc).\n%s\n",
             fail.message);
      exit_status = 1;
      goto END;
    }
    printf("   Number of Levels : %20" NAG_IFMT "\n", nwl);
    printf("   Number of coefficients in each level : %20" NAG_IFMT "\n", na);
    printf("   Wavelet coefficients C : \n");
    for (i = 0; i < nwc; i++)
      printf("%8.4f%s", c[i], (i + 1) % 8 ? " " : "\n");
    printf("\n\n");
    /*           Reconstruct original data */
    nwlinv = nwl;
    /*
     * nag_wav_dim1_mxolap_multi_inv (c09ddc)
     * one-dimensional inverse multi-level discrete wavelet transform
     * (imlmodwt)
     */
    nag_wav_dim1_mxolap_multi_inv(nwlinv, keepnum, nwc, c, n, y, icomm, &fail);
    if (fail.code != NE_NOERROR) {
      printf("Error from nag_wav_dim1_mxolap_multi_inv (c09ddc).\n%s\n",
             fail.message);
      exit_status = 1;
      goto END;
    }
    printf("   Reconstruction              Y : \n");
    for (i = 0; i < n; i++)
      printf("%8.4f%s", y[i], (i + 1) % 8 ? " " : "\n");
    printf("\n");
  }

END:
  NAG_FREE(c);
  NAG_FREE(x);
  NAG_FREE(y);
  NAG_FREE(icomm);

  return exit_status;
}