YEAR_FRACTION Function

Evaluates the fraction of a year represented by the number of whole days between two dates.

Usage

result = YEAR_FRACTION(date_start, date_end, basis)

Input Parameters

date_start—Initial date. For a more detailed discussion on dates see Chapter 8, Working with Date/Time Data in the PV‑WAVE User Guide.

date_end—Ending date. For a more detailed discussion on dates see Chapter 8, Working with Date/Time Data in the PV‑WAVE User Guide.

basis—The method for computing the number of days between two dates. It should be 0, 1, 2, 3, or 4.

0—Actual/Actual

1—US (NASD) 30/360

2—Actual/360

3—Actual/365

4—European 30/360

Returned Value

result—The fraction of a year represented by the number of whole days between two dates. If no result can be computed, NaN is returned.

Input Keywords

Double—If present and nonzero, double precision is used.

Discussion

Function YEAR_FRACTION computes the fraction of the year.

It is computed using the following:

A/D

where A = the number of days from start to end, D = annual basis.

Example

In this example, YEAR_FRACTION computes the year fraction between August 1, 2000, and July 1, 2001, using the US (NASD) 30/360 day count method.

date_start = VAR_TO_DT(2000, 8, 1)

date_end = VAR_TO_DT(2001, 7, 1)

basis = 1

PRINT, YEAR_FRACTION(date_start, date_end, basis)

; PV-WAVE prints: 0.916667