Maxima distinguishes between mathematical functions (like sin, abs, etc.)
and computational routines (like factor, ratsimp, etc.).
Mathematical functions are not "evaluated", but "simplified": sin(%pi) => 0
by simplification, sin(3.14) => 0.002 by simplification, etc. This is an
important and fundamental concept in Maxima.
There is some overlap between mathematical functions and computational
routines. For example, "integrate" can be considered as a routine which
calculates an integral, or a mathematical operator which *represents* an
integral. The function application 'integrate(...) represents the
mathematical operator, while the routine application integrate(...) tries to
calculate the integral (and if it can't, will return an expression involving
the *operator*).
'(...) suppresses evaluation but not simplification within the parentheses.
Turning off simplification (simp:false) suppresses simplification. But this
is almost never a good idea, since most of Maxima only works correctly on
simplified expressions.
-s
On Mon, Oct 5, 2009 at 10:20 AM, Leo Butler <l.butler at ed.ac.uk> wrote:
> Could someone explain to me this behaviour? It seems to me that single
> quote is not inhibiting evaluation. Leo.
>
> (%i2) 'sin(1.0);
>
> (%o2) .8414709848078965
> (%i3) '(sin(1.0));
>
> (%o3) .8414709848078965
> (%i4) ? '
>
> -- Operator: '
> The single quote operator `'' prevents evaluation.
>
> Applied to a symbol, the single quote prevents evaluation of the
> symbol.
>
> Applied to a function call, the single quote prevents evaluation
> of the function call, although the arguments of the function are
> still evaluated (if evaluation is not otherwise prevented). The
> result is the noun form of the function call.
>
> Applied to a parenthesized expression, the single quote prevents
> evaluation of all symbols and function calls in the expression.
> E.g., `'(f(x))' means do not evaluate the expression `f(x)'.
> `'f(x)' (with the single quote applied to `f' instead of `f(x)')
> means return the noun form of `f' applied to `[x]'.
>
>
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