21.8 Maximum and Minimum values

The following functions find the maximum and minimum values of a dataset (or their indices). If the data contains NaNs then a NaN will be returned, since the maximum or minimum value is undefined. For functions which return an index, the location of the first NaN in the array is returned.

Function: double gsl_stats_max (const double data[], size_t stride, size_t n)

This function returns the maximum value in data, a dataset of length n with stride stride. The maximum value is defined as the value of the element x_i which satisfies x_i >= x_j for all j.

If you want instead to find the element with the largest absolute magnitude you will need to apply fabs or abs to your data before calling this function.

Function: double gsl_stats_min (const double data[], size_t stride, size_t n)

This function returns the minimum value in data, a dataset of length n with stride stride. The minimum value is defined as the value of the element x_i which satisfies x_i <= x_j for all j.

If you want instead to find the element with the smallest absolute magnitude you will need to apply fabs or abs to your data before calling this function.

Function: void gsl_stats_minmax (double * min, double * max, const double data[], size_t stride, size_t n)

This function finds both the minimum and maximum values min, max in data in a single pass.

Function: size_t gsl_stats_max_index (const double data[], size_t stride, size_t n)

This function returns the index of the maximum value in data, a dataset of length n with stride stride. The maximum value is defined as the value of the element x_i which satisfies x_i >= x_j for all j. When there are several equal maximum elements then the first one is chosen.

Function: size_t gsl_stats_min_index (const double data[], size_t stride, size_t n)

This function returns the index of the minimum value in data, a dataset of length n with stride stride. The minimum value is defined as the value of the element x_i which satisfies x_i >= x_j for all j. When there are several equal minimum elements then the first one is chosen.

Function: void gsl_stats_minmax_index (size_t * min_index, size_t * max_index, const double data[], size_t stride, size_t n)

This function returns the indexes min_index, max_index of the minimum and maximum values in data in a single pass.