ciabatta/test/math.c

131 lines
5.0 KiB
C

#include <stdio.h>
#include <math.h>
#include <float.h>
#include <fenv.h>
#include <inttypes.h>
#include <errno.h>
#include <limits.h>
const char *show_classification(double x) {
switch(fpclassify(x)) {
case FP_INFINITE: return "Inf";
case FP_NAN: return "NaN";
case FP_NORMAL: return "normal";
case FP_SUBNORMAL: return "subnormal";
case FP_ZERO: return "zero";
default: return "unknown";
}
}
int main() {
printf("\n=== fpclassify === \n");
double zero = 0.0; // fucken msvc
printf("1.0/0.0 is %s\n", show_classification(1.0/zero));
printf("0.0/0.0 is %s\n", show_classification(0.0/zero));
printf("DBL_MIN/2 is %s\n", show_classification(DBL_MIN/2));
printf("-0.0 is %s\n", show_classification(-0.0));
printf("1.0 is %s\n", show_classification(1.0));
printf("\n\n=== nearbyint === \n");
double d;
printf("nearbyint(+0.0) = %f\n", d=nearbyint(+0.0));
printf("nearbyint(-0.0) = %f\n", d=nearbyint(-0.0));
printf("nearbyint(+16.4) = %f\n", d=nearbyint(+16.4));
printf("nearbyint(+16.5) = %f\n", d=nearbyint(+16.5));
printf("nearbyint(+16.8) = %f\n", d=nearbyint(+16.8));
printf("\n\n=== signbit === \n");
printf("signbit(+0.0) = %d\n", signbit(+0.0));
printf("signbit(-0.0) = %d\n", signbit(-0.0));
printf("\n\n=== copysign === \n");
printf("copysign(1.0,+2.0) = %f\n", copysign(1.0,+2.0));
printf("copysign(1.0,-2.0) = %f\n", copysign(1.0,-2.0));
printf("copysign(INFINITY,-2.0) = %f\n", copysign(INFINITY,-2.0));
printf("copysign(NAN,-2.0) = %f\n", copysign(NAN,-2.0));
printf("\n\n=== rint === \n");
fesetround(FE_TONEAREST);
printf("rounding to nearest (halfway cases to even):\n"
"rint(+2.3) = %f ", rint(2.3));
printf("rint(+2.5) = %f ", rint(2.5));
printf("rint(+3.5) = %f\n", rint(3.5));
printf("rint(-2.3) = %f ", rint(-2.3));
printf("rint(-2.5) = %f ", rint(-2.5));
printf("rint(-3.5) = %f\n", rint(-3.5));
fesetround(FE_DOWNWARD);
printf("rounding down: \nrint(+2.3) = %f ", rint(2.3));
printf("rint(+2.5) = %f ", rint(2.5));
printf("rint(+3.5) = %f\n", rint(3.5));
printf("rint(-2.3) = %f ", rint(-2.3));
printf("rint(-2.5) = %f ", rint(-2.5));
printf("rint(-3.5) = %f\n", rint(-3.5));
feclearexcept(FE_ALL_EXCEPT);
printf("rint(1.1) = %f\n", rint(1.1));
if(fetestexcept(FE_INEXACT)) printf(" FE_INEXACT was raised\n");
printf("\n\n=== nextafter === \n");
float from1 = 0, to1 = nextafterf(from1, 1);
printf("The next representable float after %f is %f\n", from1, to1);
float from2 = 1, to2 = nextafterf(from2, 2);
printf("The next representable float after %f is %f\n", from2, to2);
float from5 = 0.0, to5 = nextafter(from5, -0.0);
printf("nextafter(+0.0, -0.0) gives %f (%f)\n", to5, to5);
printf("\n\n=== ceil === \n");
printf("ceil(+2.4) = %f\n", ceil(2.4));
printf("ceil(-2.4) = %f\n", ceil(-2.4));
printf("ceil(-0.0) = %f\n", ceil(-0.0));
printf("ceil(-Inf) = %f\n", ceil(-INFINITY));
printf("\n\n=== floor === \n");
printf("floor(+2.7) = %f\n", floor(2.7));
printf("floor(-2.7) = %f\n", floor(-2.7));
printf("floor(-0.0) = %f\n", floor(-0.0));
printf("floor(-Inf) = %f\n", floor(-INFINITY));
printf("\n\n=== trunk === \n");
printf("trunc(+2.7) = %f\n", trunc(2.7));
printf("trunc(-2.7) = %f\n", trunc(-2.7));
printf("trunc(-0.0) = %f\n", trunc(-0.0));
printf("trunc(-Inf) = %f\n", trunc(-INFINITY));
printf("\n\n=== round === \n");
printf("round(+2.3) = %f ", round(2.3));
printf("round(+2.5) = %f ", round(2.5));
printf("round(+2.7) = %f\n", round(2.7));
printf("round(-2.3) = %f ", round(-2.3));
printf("round(-2.5) = %f ", round(-2.5));
printf("round(-2.7) = %f\n", round(-2.7));
printf("round(-0.0) = %f\n", round(-0.0));
printf("round(-Inf) = %f\n", round(-INFINITY));
printf("lround(+2.3) = %ld ", lround(2.3));
printf("lround(+2.5) = %ld ", lround(2.5));
printf("lround(+2.7) = %ld\n", lround(2.7));
printf("lround(-2.3) = %ld ", lround(-2.3));
printf("lround(-2.5) = %ld ", lround(-2.5));
printf("lround(-2.7) = %ld\n", lround(-2.7));
printf("lround(-0.0) = %ld\n", lround(-0.0));
printf("lround(-Inf) = %ld\n", lround(-INFINITY));
feclearexcept(FE_ALL_EXCEPT);
printf("lround(LONG_MAX+1.5) = %ld\n", lround(LONG_MAX+1.5));
if(fetestexcept(FE_INVALID)) printf(" FE_INVALID was raised\n");
printf("\n\n=== exp === \n");
printf("exp(1) = %e\n", exp(1));
printf("FV of $100, continuously compounded at 3%% for 1 year = %e\n",
100*exp(0.03));
// special values
printf("exp(-0) = %e\n", exp(-0.0));
printf("exp(-Inf) = %e\n", exp(-INFINITY));
//error handling
errno = 0; feclearexcept(FE_ALL_EXCEPT);
printf("exp(710) = %e\n", exp(710));
if(errno == ERANGE) printf(" errno == ERANGE\n");
if(fetestexcept(FE_OVERFLOW)) printf(" FE_OVERFLOW raised\n");
return 0;
}