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
