Basic Types and Conversions

Maple has a large number of object types.  Typical types of numeric
values are integer, float (floating-point or pseudo-real), fraction,
rational, and boolean.  Some of the more complex object types include
string, polynom (polynomial expression), series, matrix, vector, set,
list, and procedure.

Integers are expressed as a string of one or more digits with an
optional sign, like "-2" or "3870".  Rational numbers are a signed ratio
of unsigned integers, like "2/3" or "-8/30", and will be simplified by
Maple:

> -8/30;
-4/15

Floating point numbers contain an explicit decimal point, and any
integer or rational expression that contains such a decimal point will
be evaluated as floating point:

> 2/3;
2/3
> 2.0/3.0;
.6666666667

Maple has a global variable named "Digits" that you use to control the
accuracy of floating-point operations.  The initial setting for Digits
is 10 but you can change it by assigning it some other value:

> Digits:=5;
Digits := 5
> 2.0/3.0;
.66667
> Digits:=10;
Digits := 10
> "";
.66667
> 2.0/3.0;
.6666666667

Notice that the value of Digits does not control the display of floating
point values, it controls their calculation.  If you calculate something
with one value for Digits, then change Digits to a new value, then only
future floating-point operations will reflect the change.

You can perform conversions between various Maple datatypes.  One way is
to force evaluation of expressions in the type you want.  For example to
convert a rational expression to floating point, you could use the evalf
function:

> evalf(2/3);
.6666666667
> evalf(2/3, 5);
.66667

As you can see, evalf also provides a way to temporarily control the
accuracy of floating-point calculations.  See help('eval') for
information on other Maple evaluation functions.

The second, more general, way to convert between types is to use the
convert function.  See help('convert') for more information.