tanh

Interface Definition

C interface:

float tanhf(float x);

double tanh(double x);

Fortran interface:

RES = TANHF(X)

RES = TANH(X)

Parameters

Return Value

• Return the hyperbolic tangent function value y of the radian angle x. y ∈ [-1, +1].
• If the input is +0, the return value is +0.
• If the input is -0, the return value is -0.
• If the input is +∞, the return value is +1.
• If the input is -∞, the return value is -1.
• If the input is NaN, the return value is NaN.

Dependencies

C: "km.h"

Fortran: "km.f03"

Examples

C interface:

    double pi = acos(-1); 
    // typical usage 
    double a = pi/3, c = -3*pi/4, d = 0.0; 
    // special handling 
    double b = pi/2, e = INFINITY, f = -INFINITY, g = NAN; 
    // print result 
    printf("tanh(pi/3) = %.15f\n", tanh(a)); 
    printf("tanh(-3*pi/4) = %.15f\n", tanh(c)); 
    printf("tanh(0.0) = %.15f\n", tanh(d)); 
    // mathematical poles 
    printf("tanh(pi/2) = %.15f\n", tanh(b)); 
    printf("tanh(INFINITY) = %.15f\n", tanh(e)); 
    printf("tanh(-INFINITY) = %.15f\n", tanh(f)); 
    printf("tanh(NAN) = %.15f\n", tanh(g)); 
    /* 
     *  tanh(pi/3) = 0.780714435359268 
     *  tanh(-3*pi/4) = -0.982193380007239 
     *  tanh(0.0) = 0.000000000000000 
     *  tanh(pi/2) = 0.917152335667274 
     *  tanh(INFINITY) = 1.000000000000000
     *  tanh(-INFINITY) = -1.000000000000000
     *  tanh(NAN) = nan 
     * 
     * */

Fortran interface:

    REAL(8) :: X = 0.0 
    PRINT*,  TANH(X) 
    ! 
    ! OUTPUT 
    !     0.000000000000000 
    !