histogram.h File Reference

Keep counts of doubles that fall in some given bucket size. More...

#include "int_sizes.h"

Go to the source code of this file.

Functions
struct histogram *	histogram_create (double bucket_size)
	Create a new histogram. More...
void	histogram_clear (struct histogram *h)
	Remove all entries from a histogram. More...
void	histogram_delete (struct histogram *h)
	Delete a histogram. More...
int	histogram_size (struct histogram *h)
	Count the number of active buckets. More...
double *	histogram_buckets (struct histogram *h)
	Returns an ordered array with the start values of the active buckets. More...
double	histogram_bucket_size (struct histogram *h)
	Returns the bucket size. More...
int	histogram_insert (struct histogram *h, double value)
	Add value to histogram. More...
int	histogram_count (struct histogram *h, double value)
	Look up the count for the bucket of the given value. More...
void	histogram_set_bucket (struct histogram *h, double value, int count)
	Manually set the count for a bucket. More...
void	histogram_attach_data (struct histogram *h, double value, void *data)
	Attach custom data to bucket. More...
void *	histogram_get_data (struct histogram *h, double value)
	Retrieved custom data attached to the bucket. More...
int	histogram_total_count (struct histogram *h)
	Return the total number of samples in the histogram. More...
double	histogram_max_value (struct histogram *h)
	Return the maximum value inserted in the histogram. More...
double	histogram_min_value (struct histogram *h)
	Return the minimum value inserted in the histogram. More...
double	histogram_round_up (struct histogram *h, double test_value)
	Return the largest value of the bucket that test_value would faill in. More...
double	histogram_mode (struct histogram *h)
	Return the mode of the histogram. More...

Detailed Description

Keep counts of doubles that fall in some given bucket size.

struct histogram *h;
double bucket_size = .5;
h = histogram_create(bucket_size);

// same bucket
histogram_insert(h, 3.0);
histogram_insert(h, 3.1415);

// same bucket
histogram_insert(h, 21.999);

// same bucket
histogram_insert(h, 22.0);
histogram_insert(h, 22.2);
histogram_insert(h, 22.499);

// same bucket
histogram_insert(h, 22.5);

// same bucket
histogram_insert(h, -21.999);

// same bucket
histogram_insert(h, -22.0);
histogram_insert(h, -22.2);
histogram_insert(h, -22.499);

// same bucket
histogram_insert(h, -22.5);

double *buckets = histogram_buckets(h);
double b        = histogram_bucket_size(h);

int i;
for(i = 0; i < histogram_size(h); i++) {

    double start = buckets[i];

    fprintf(stdout, "[%lf, $lf) has %d elements.\n", start, start + b, histogram_count(h, start));

}

free(buckets);
histogram_delete(h);

Function Documentation

struct histogram* histogram_create

(

double

bucket_size

)

Create a new histogram.

Parameters

bucket_size

Numbers are grouped according to [n*bucket_size, (n+1)*bucket_size), n in Z.

Returns

A pointer to a new histogram.

void histogram_clear

(

struct histogram *

h

)

Remove all entries from a histogram.

Parameters

h	The histogram to clear.

void histogram_delete

(

struct histogram *

h

)

Delete a histogram.

Parameters

h	The histogram to delete.

int histogram_size

(

struct histogram *

h

)

Count the number of active buckets.

Returns

The number of active buckets in the histogram.

Parameters

h	A pointer to a histogram.

double* histogram_buckets

(

struct histogram *

h

)

Returns an ordered array with the start values of the active buckets.

double histogram_bucket_size

(

struct histogram *

h

)

Returns the bucket size.

int histogram_insert	(	struct histogram *	h,
		double	value
	)

Add value to histogram.

Parameters

h	A pointer to a histogram.
value	A number to add to the histogram.

Returns

The updated count of the respective bucket.

int histogram_count	(	struct histogram *	h,
		double	value
	)

Look up the count for the bucket of the given value.

Parameters

h	A pointer to a histogram.
value	A number that would fall inside the desired bucket.

Returns

The count for the bucket.

void histogram_set_bucket	(	struct histogram *	h,
		double	value,
		int	count
	)

Manually set the count for a bucket.

Parameters

h	A pointer to a histogram.
value	A number that would fall inside the desired bucket.
count	The desired count.

void histogram_attach_data	(	struct histogram *	h,
		double	value,
		void *	data
	)

Attach custom data to bucket.

Parameters

h	A pointer to a histogram.
value	A number that would fall inside the desired bucket.
data	A pointer to external data.

void* histogram_get_data	(	struct histogram *	h,
		double	value
	)

Retrieved custom data attached to the bucket.

Parameters

h	A pointer to a histogram.
value	A number that would fall inside the desired bucket.

Returns

A pointer to external data.

int histogram_total_count

(

struct histogram *

h

)

Return the total number of samples in the histogram.

Parameters

h	A pointer to a histogram.

Returns

Count of all the samples.

double histogram_max_value

(

struct histogram *

h

)

Return the maximum value inserted in the histogram.

Parameters

h	A pointer to a histogram.

Returns

Maximum value inserted.

double histogram_min_value

(

struct histogram *

h

)

Return the minimum value inserted in the histogram.

Parameters

h	A pointer to a histogram.

Returns

Minimum value inserted.

double histogram_round_up	(	struct histogram *	h,
		double	test_value
	)

Return the largest value of the bucket that test_value would faill in.

Parameters

h	A pointer to a histogram.
test_value	value to round up

Returns

test_value rounded up according to bucket size.

double histogram_mode

(

struct histogram *

h

)

Return the mode of the histogram.

Parameters

h	A pointer to a histogram.

Returns

Histogram mode.