ChapterHistogram

Histogram

Histogram of a real array.

Loading LOADSUB ALL FROM "HIST.HTS"

or LOADSUB FROM "MATHLIB.HTS"

or LOADSUB Histogram FROM "MATHLIB.HTS"

Usage INTEGER N,Hist(*)

REAL Xmin,Xmax,A(*)

CALL Histogram(A(*),Xmin,Xmax,N,Hist(*))

Description

Histogram divides the region of values between xmin and xmax into n equal intervals and counts the number of elements in the array A whose values lie in each interval. If a value in A lies below xmin or at or above xmax, it is not counted. If a value is exactly the value that separates two intervals, it is counted in the higher of the two intervals.

Histogram counts in the following manner: Let s be the width of an interval in which values are counted. S is defined by the expression

If a value in A falls between xmin, inclusive, and xmin+s, exclusive, the count in the first element of Hist is increased. If the value falls between xmin+s, inclusive, and xmin+2s, exclusive, the count in the second element of Hist is increased, etc.

Hist must contain at least n elements.

Errors

Histogram causes an HTBasic error if its arguments are not of the types listed in the USAGE section, above, if xmin xmax, if n is negative or zero, or if Hist contains fewer than n elements.