FINITE Function

PV-WAVE Foundation > Reference Guide > Procedure and Function Reference: F > FINITE Function

FINITE Function

Returns a value indicating if the input variable is finite or not.

Usage

result = FINITE(x)

Input Parameters

x—A scalar or array expression of single-precision complex, double-precision complex, single-precision floating point, or double-precision floating point data type.

Returned Value

result—Returns 1 if x is finite. Returns 0 if x is infinite or not a defined number (NaN). Undefined numbers result from ill-defined operations, such as dividing zero by zero, or taking the logarithm of zero or a negative number.

Keywords

None.

Example 1

x = [100, SQRT(-1), ALOG(0), 99.9]

PM, x

; On UNIX systems, PV-WAVE prints:

;      100.000

;          NaN

;         -Inf

;      99.9000

; On Windows systems, PV-WAVE prints:

;       100.000

;      -1.#IND0

;      -1.#INF0

;       99.9000

PM, FINITE(x)

; PV-WAVE prints:

;       1

;       0

;       0

;       1

Example 2

; NOTE: This example requires PV-WAVE Advantage.

; Get the single-precision, floating-point machine constants.

MATH_INIT

fmach = MACHINE(/Float)

; Create a five-element vector containing single-precision,

; floating-point NaN, positive infinity, negative infinity, and

; finite values.

a = [fmach.nan, 3.0, fmach.pos_inf, 5.2, fmach.neg_inf]

b = FINITE(a)

; View result of FINITE.

INFO, b

; PV-WAVE prints: B          BYTE         = Array(5)

; Print vectors a and b. Note that vector b contains a 0

; when NaN or infinity occurs in a. Vector b contains 1 at

; the indices where vector a contains finite values.

FOR i=0L, 4 DO PRINT, a(i), b(i)

; On UNIX systems, PV-WAVE prints:

;   NaN       0

;   3.00000   1

;   Inf       0

;   5.20000   1

;   -Inf      0

; On Windows systems, PV-WAVE prints:

;   1.#QNAN   0

;   3.00000   1

;   1.#INF0   0

;   5.20000   1

;  -1.#INF0   0