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21.2.13 Primitive Numeric Functions
Many of Guile's numeric procedures which accept any kind of numbers as
arguments, including complex numbers, are implemented as Scheme
procedures that use the following real number-based primitives. These
primitives signal an error if they are called with complex arguments.
|
Return the absolute value of x.
|
|
Return the square root of x.
|
| $expt x y
|
Scheme Procedure |
| scm_sys_expt (x, y)
|
C Function |
|
Return x raised to the power of y. This
procedure does not accept complex arguments.
|
|
Return the arccosine of x.
|
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Return the arctangent of x in the range -PI/2 to PI/2.
|
| $atan2 x y
|
Scheme Procedure |
| scm_sys_atan2 (x, y)
|
C Function |
|
Return the arc tangent of the two arguments x and
y. This is similar to calculating the arc tangent of
x / y, except that the signs of both arguments
are used to determine the quadrant of the result. This
procedure does not accept complex arguments.
|
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Return e to the power of x, where e is the base of natural
logarithms (2.71828...).
|
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Return the natural logarithm of x.
|
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Return the hyperbolic sine of x.
|
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Return the hyperbolic cosine of x.
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Return the hyperbolic tangent of x.
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| $asinh x
|
Scheme Procedure |
|
Return the hyperbolic arcsine of x.
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| $acosh x
|
Scheme Procedure |
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Return the hyperbolic arccosine of x.
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| $atanh x
|
Scheme Procedure |
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Return the hyperbolic arctangent of x.
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For the hyperbolic arc-functions, the Guile library exports C functions
corresponding to these Scheme procedures, but taking and returning
arguments of type double rather than the usual SCM.
| double scm_asinh (double x)
|
C Function |
| double scm_acosh (double x)
|
C Function |
| double scm_atanh (double x)
|
C Function |
|
Return the hyperbolic arcsine, arccosine or arctangent of x
respectively.
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For all the other Scheme procedures above, except expt and
atan2 (whose entries specifically mention an equivalent C
function), the equivalent C functions are those provided by the standard
mathematics library. The mapping is as follows.
| Scheme Procedure | C Function
|
| $abs | fabs
|
| $sqrt | sqrt
|
| $sin | sin
|
| $cos | cos
|
| $tan | tan
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| $asin | asin
|
| $acos | acos
|
| $atan | atan
|
| $exp | exp
|
| $log | log
|
| $sinh | sinh
|
| $cosh | cosh
|
| $tanh | tanh
|
Naturally, these C functions expect and return double arguments.