| VPF_logtoC | VPD_logtoC | VPE_logtoC |
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| Function | Natural logarithm |
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| Syntax C/C++ | #include <VFmath.h>
int VF_log( fVector Y, fVector X, ui size );
int VFx_log( fVector Y, fVector X, ui size, float A, float B, float C );
int VPF_logtoC( cfVector Y, pfVector X, ui size ); |
| C++ VecObj | #include <OptiVec.h>
int vector<T>::log( const vector<T>& X );
int vector<T>::x_log( const vector<T>& X, const T& A, const T& B, const T& C );
int vector<complex<T>>::logtoC( const vector<polar<T>>& X ); |
| Pascal/Delphi | uses VFmath;
function VF_log( Y, X:fVector; size:UInt ): IntBool;
function VFx_log( Y, X:fVector; size:UInt; A, B, C:Single ): IntBool;
function VPF_logtoC( Y:cfVector; X:pfVector; size:UInt ): IntBool; |
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| Description | normal versions: Yi = ln( Xi )
expanded versions: Yi = C * ln( A*Xi+B )
The "logarithmus naturalis", i.e. the logarithm to the basis of Euler's constant e is calculated.
The logarithm of polar complex numbers is most naturally stored in cartesian format, as log{Mag@Arg} = {Mag,Arg}. Therefore, the VPF_ version exists only with the result in a cfVector. |
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| Error handling | Real versions: DOMAIN errors occur in the case of negative Xi (including -0.0), with NAN ("not-a-number") as the default result. SING errors occur for Xi= +0.0 and yield a result of -HUGE_VAL. In the complex version, numbers with an imaginary part of zero are always treated as real numbers; therefore, an argument {0, 0} is treated as a real 0, causing a SING error with the default result {-HUGE_VAL, 0}. |
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| Return value | FALSE (0), if no error occurred, otherwise TRUE (non-zero) |
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