On Wed, 25 Feb 2009, Barton Willis wrote:
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implemented.?One?point?is?that?the?$sign?function?does?a?numerically
>evaluation of?the?expression.
Right--also the option variable signbfloat controls this:
(%i17) is(equal(%e^(log(2)/2)-1 , (sqrt(2)-1))), signbfloat : true;
(%o17) false
(%i18) is(equal(%e^(log(2)/2)-1 , (sqrt(2)-1))), signbfloat : false;
(%o18) unknown
In (%o17) Maxima returns false for a spurious reason. Some time ago
I think I tried building Maxima with signbfloat : false as the default.
It didn't break all that many tests; should we consider signbfloat : false?
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I can't find any documentation for signbfloat.
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(%i1) ?? bfloat
0: bfloat (Functions and Variables for Floating Point)
1: bfloatp (Functions and Variables for Floating Point)
Enter space-separated numbers, `all' or `none': 0;
-- Function: bfloat (<expr>)
Converts all numbers and functions of numbers in <expr> to
bigfloat numbers. The number of significant digits in the
resulting bigfloats is specified by the global variable `fpprec'.
When `float2bf' is `false' a warning message is printed when a
floating point number is converted into a bigfloat number (since
this may lead to loss of precision).
(%o1) true
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Ted Woollett