— Function: int gsl_histogram_equal_bins_p (const gsl_histogram * h1, const gsl_histogram * h2)

This function returns 1 if the all of the individual bin ranges of the two histograms are identical, and 0 otherwise.

— Function: int gsl_histogram_add (gsl_histogram * h1, const gsl_histogram * h2)

This function adds the contents of the bins in histogram h2 to the corresponding bins of histogram h1, i.e. h'_1(i) = h_1(i) + h_2(i). The two histograms must have identical bin ranges.

— Function: int gsl_histogram_sub (gsl_histogram * h1, const gsl_histogram * h2)

This function subtracts the contents of the bins in histogram h2 from the corresponding bins of histogram h1, i.e. h'_1(i) = h_1(i) - h_2(i). The two histograms must have identical bin ranges.

— Function: int gsl_histogram_mul (gsl_histogram * h1, const gsl_histogram * h2)

This function multiplies the contents of the bins of histogram h1 by the contents of the corresponding bins in histogram h2, i.e. h'_1(i) = h_1(i) * h_2(i). The two histograms must have identical bin ranges.

— Function: int gsl_histogram_div (gsl_histogram * h1, const gsl_histogram * h2)

This function divides the contents of the bins of histogram h1 by the contents of the corresponding bins in histogram h2, i.e. h'_1(i) = h_1(i) / h_2(i). The two histograms must have identical bin ranges.

— Function: int gsl_histogram_scale (gsl_histogram * h, double scale)

This function multiplies the contents of the bins of histogram h by the constant scale, i.e. h'_1(i) = h_1(i) * scale.

— Function: int gsl_histogram_shift (gsl_histogram * h, double offset)

This function shifts the contents of the bins of histogram h by the constant offset, i.e. h'_1(i) = h_1(i) + offset.