Does `log`

need to be computed using floating-point representation?
This excludes the larger part of bignums.

This is a test:

```
(define x (expt 10 2480))
(log x)
```

If the implementation wants to answer `(log x)`

with the correct
number, the logarithm must be calculated without the floating-point
C library log function, since the number is far too large to fit
in current days 64-bit doubles.

System | result |
---|---|

Bigloo | -inf.0 |

Biwa | +inf.0 |

Chez | 5710.411030625233 |

Chibi | +inf.0 |

Chicken | +inf.0 |

Cyclone | +inf.0 |

Foment | +inf.0 |

Gambit | 5710.411030625233 |

Gauche | 5710.411030625233 |

Guile | 5710.411030625233 |

Kawa | +inf.0 |

LIPS | +inf.0 |

Loko | +inf.0 |

MIT | +inf.0 |

Racket | 5710.411030625233 |

Sagittarius | 5710.411030625233 |

Scheme 9 | 5710.41103062521399 |

STklos | +inf.0 |

Tinyscheme | +inf.0 |

Unsyntax | +inf.0 |

Ypsilon | 5710.411030625233 |

ABCL | error |

CCL | 5710.411 |

Clisp | 5710.411 |

CMUCL | 5710.411 |

ECL | 5710.411 |

SBCL | 5710.411 |

Emacs Lisp | 1.0e+INF |

- Biwa and Tinyscheme already compute
`x`

as the inexact infinity`+inf.0`

.

Another experiment:

`(log 1/6319748715279270675921934218987893281199411530039296)`

Should return -119.27551918982401. (This was posted to the ECL mailing list on 2022-Jul-03 -- ECL does not compute the value, and complains about the user requesting log of zero).

- Cyclone needs the number to be given as explicit division (doesn't support rationals), and returns
`-inf.0`

- Loko returns
`-inf.0`

- Tinyscheme needs the number to be given as explicit division (doesn't support rationals), and returns
`-43.66827238`

All others return the correct result; Bigloo and Scheme9 need the rational to be described as division, not as rational type.