Compute a Bessel function of the first kind of order 0
#include <math.h> double j0( double x ); float j0f( float x );
These functions compute the Bessel function for x of the first kind of order 0.
To check for error situations, use feclearexcept() and fetestexcept(). For example:
The Bessel value of x of the first kind of order 0.
If: | These functions return: | Errors: |
---|---|---|
x is ±0.0 | 1.0 | — |
x is ±Inf | 0.0 | — |
x is NaN | NaN | — |
The correct result would cause underflow | 0.0 | FE_UNDERFLOW |
These functions raise FE_INEXACT if the FPU reports that the result can't be exactly represented as a floating-point number.
#include <stdio.h> #include <math.h> #include <fenv.h> #include <stdlib.h> int main( void ) { int except_flags; double x, y, z; feclearexcept(FE_ALL_EXCEPT); x = j0( 2.4 ); except_flags = fetestexcept(FE_ALL_EXCEPT); if(except_flags) { /* An error occurred; handle it appropriately. */ } feclearexcept(FE_ALL_EXCEPT); y = y1( 1.58 ); except_flags = fetestexcept(FE_ALL_EXCEPT); if(except_flags) { /* An error occurred; handle it appropriately. */ } feclearexcept(FE_ALL_EXCEPT); z = jn( 3, 2.4 ); except_flags = fetestexcept(FE_ALL_EXCEPT); if(except_flags) { /* An error occurred; handle it appropriately. */ } printf( "j0(2.4) = %f, y1(1.58) = %f\n", x, y ); printf( "jn(3,2.4) = %f\n", z ); return EXIT_SUCCESS; }
j0() is POSIX 1003.1 XSI; j0f() is Unix
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | No |
Thread | Yes |