CINH

This function evaluates a function closely related to the hyperbolic cosine integral.

Function Return Value

CINH — Function value. (Output)

Required Arguments

X — Argument for which the function value is desired. (Input)

FORTRAN 90 Interface

Generic: CINH (X)

Specific: The specific interface names are S_CINH and D_CINH.

FORTRAN 77 Interface

Single: CINH (X)

Double: The double precision function name is DCINH.

Description

The alternate definition of the hyperbolic cosine integral, Cinh(x), is

 

For

 

where s = AMACH(1) is the smallest representable positive number, the result underflows. The argument x must be large enough that e−x/x does not underflow, and x must be small enough that ex does not overflow.

Comments

Informational Error

 

Type	Code	Description
2	1	The function underflows because X is too small.

Example

In this example, Cinh(2.5) is computed and printed.

 

USE CINH_INT

USE UMACH_INT

 

IMPLICIT NONE

! Declare variables

INTEGER NOUT

REAL VALUE, X

! Compute

X = 2.5

VALUE = CINH(X)

! Print the results

CALL UMACH (2, NOUT)

WRITE (NOUT,99999) X, VALUE

99999 FORMAT (' CINH(', F6.3, ') = ', F6.3)

END

Output

 

CINH( 2.500) = 2.031