5.2.5 vsip_dcorr1d_create_p - Create 1D Correlation Object

typedef enum _vsip_support_region { 
  VSIP_SUPPORT_FULL = 0, 
  VSIP_SUPPORT_SAME = 1, 
  VSIP_SUPPORT_MIN  = 2, 
} vsip_support_region; 
 
typedef enum _vsip_alg_hint { 
  VSIP_ALG_TIME  = 0, 
  VSIP_ALG_SPACE = 1, 
  VSIP_ALG_NOISE = 2 
} vsip_alg_hint; 
 
vsip_corr1d_f* vsip_corr1d_create_f(vsip_length m, vsip_length n, vsip_support_region support, vsip_length ntimes, vsip_alg_hint hint); 
vsip_ccorr1d_f* vsip_ccorr1d_create_f(vsip_length m, vsip_length n, vsip_support_region support, vsip_length ntimes, vsip_alg_hint hint);

Description

This function creates a one-dimensional correlation object that can be used to compute the correlation between an input signal and a reference signal.

The correlation object is optimized for repeated use, allowing efficient computation of correlations between signals of length and reference signals of length .

Parameters

• vsip_length m: Length of the input signal.

• vsip_length n: Length of the reference signal.

• vsip_support_region support: Specifies the support region for the correlation:

  • VSIP_SUPPORT_FULL: Compute full correlation. Output length is .

  • VSIP_SUPPORT_SAME: Compute correlation with same-length output .

  • VSIP_SUPPORT_MIN: Compute minimum-length correlation. Output length is .

• vsip_length ntimes: Number of times the correlation will be applied.

• vsip_alg_hint hint: Algorithm hint for optimization:

  • VSIP_ALG_TIME: Optimize for computation time

  • VSIP_ALG_SPACE: Optimize for memory usage

  • VSIP_ALG_NOHINT: No specific optimization

Return Value

• On success: Pointer to the newly created 1D correlation object.

• On error (e.g., memory allocation failure): NULL.

Example

vsip_corr1d_f *corr; 
vsip_length m = 1024;  // Input signal length 
vsip_length n = 64;    // Reference signal length 
vsip_length ntimes = 100; // Number of times to reuse object 
 
// Create correlation object for full correlation 
corr = vsip_corr1d_create_f(m, n, VSIP_SUPPORT_FULL, ntimes, VSIP_ALG_TIME); 
if (corr == NULL) { 
    fprintf(stderr, "Error: Could not create correlation object\n"); 
    return -1; 
} 
 
// Use the correlation object for your signal processing 
// vsip_vview_f *input = vsip_vcreate_f(m, VSIP_MEM_NONE); 
// vsip_vview_f *reference = vsip_vcreate_f(n, VSIP_MEM_NONE); 
// vsip_vview_f *result = vsip_vcreate_f(m + n - 1, VSIP_MEM_NONE); 
// 
// vsip_corr1d_f(corr, input, reference, result); 
 
// Clean up when done 
vsip_corr1d_destroy_f(corr);

Notes

• The correlation object should be destroyed with vsip_dcorr1d_destroy_p when no longer needed.

• The choice of support affects the length of the output correlation vector:

  • VSIP_SUPPORT_FULL: Output length is

  • VSIP_SUPPORT_SAME: Output length is

  • VSIP_SUPPORT_MIN: Output length is

• The ntimes parameter helps the library optimize memory allocation for repeated use.