Interface

      F_TYPE ln (F_TYPE x)

      F_TYPE log2 (F_TYPE x)

      F_TYPE log10 (F_TYPE x)

      F_TYPE log1p (F_TYPE y)

1  –  Description

    ln() computes the natural (base e) logarithm of x.

    log2() computes the base 2 logarithm of x.

    log10() computes the common (base 10) logarithm of x.

    log1p() computes ln(1+y) accurately, even for tiny y.

                           Entry-Point Names

    Generic
    Function   Data Type   OpenVMS        Tru64 UNIX
    Name       Required

    ln         S_FLOAT     math$ln_s      logf
               T_FLOAT     math$ln_t      log
               X_FLOAT     math$ln_x      logl
               F_FLOAT     math$ln_f
               G_FLOAT     math$ln_g

    log2       S_FLOAT     math$log2_s    log2f
               T_FLOAT     math$log2_t    log2
               X_FLOAT     math$log2_x    log2l
               F_FLOAT     math$log2_f
               G_FLOAT     math$log2_g

    log10      S_FLOAT     math$log10_s   log10f
               T_FLOAT     math$log10_t   log10
               X_FLOAT     math$log10_x   log10l
               F_FLOAT     math$log10_f
               G_FLOAT     math$log10_g

    log1p      S_FLOAT     math$log1p_s   log1pf
               T_FLOAT     math$log1p_t   log1p
               X_FLOAT     math$log1p_x   log1pl
               F_FLOAT     math$log1p_f
               G_FLOAT     math$log1p_g

2  –  Exceptions

    Exceptional Argument   Routine Behavior

    x < 0                  Invalid argument
    x = 0                  Overflow
    1+y < 0                Invalid argument
    1+y = 0                Overflow