本文整理汇总了C++中scalbn函数的典型用法代码示例。如果您正苦于以下问题：C++ scalbn函数的具体用法？C++ scalbn怎么用？C++ scalbn使用的例子？那么恭喜您, 这里精选的函数代码示例或许可以为您提供帮助。
在下文中一共展示了scalbn函数的15个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: test_fp_utilities
void test_fp_utilities( void )
{
#if __STDC_VERSION__ >= 199901L
printf( "Testing C99 miscellaneous functions...\n" );
VERIFY( CompDbl( copysign( -2.0, 1.0), 2.0 ) );
VERIFY( CompDbl( copysign( -2.0, -1.0), -2.0 ) );
VERIFY( CompDbl( copysign( 2.0, -1.0), -2.0 ) );
VERIFY( CompDbl( copysign( 2.0, 1.0), 2.0 ) );
VERIFY( CompDbl( fmax( 2.0, 1.0), 2.0 ) );
VERIFY( CompDbl( fmax( -2.0, -1.0), -1.0 ) );
VERIFY( CompDbl( fmin( 2.0, 1.0), 1.0 ) );
VERIFY( CompDbl( fmin( -2.0, -1.0), -2.0 ) );
VERIFY( CompDbl( fma( 2.0, 3.0, 4.0), 10.0 ) );
VERIFY( CompDbl( fma( 2.0, 3.0, -4.0), 2.0 ) );
VERIFY( CompDbl( fma( -2.0, 3.0, 4.0), -2.0 ) );
VERIFY( CompDbl( fma( -2.0, -3.0, 4.0), 10.0 ) );
VERIFY( CompDbl( fdim( 3.0, 2.0), 1.0 ) );
VERIFY( CompDbl( fdim( 2.0, 3.0), 0.0 ) );
VERIFY( CompDbl( nextafter( 1.0, 2.0), 1.0+1.0E-16 ) );
VERIFY( CompDbl( nextafter( 1.0, 0.0), 1.0-1.0E-16 ) );
VERIFY( CompDbl( scalbn( 1.0, 3.0), 8.0 ) );
VERIFY( CompDbl( scalbn( 4.0, 3.0), 32.0 ) );
#endif
}示例2: test_scalbn
void test_scalbn()
{
static_assert((std::is_same<decltype(scalbn((double)0, (int)0)), double>::value), "");
static_assert((std::is_same<decltype(scalbnf(0, (int)0)), float>::value), "");
static_assert((std::is_same<decltype(scalbnl(0, (int)0)), long double>::value), "");
assert(scalbn(1, 1) == 2);
}示例3: cexpf
fcomplex
cexpf(fcomplex z) {
fcomplex ans;
float x, y, c, s;
double t;
int n, ix, iy, hx, hy;
x = F_RE(z);
y = F_IM(z);
hx = THE_WORD(x);
hy = THE_WORD(y);
ix = hx & 0x7fffffff;
iy = hy & 0x7fffffff;
if (iy == 0) { /* y = 0 */
F_RE(ans) = expf(x);
F_IM(ans) = y;
} else if (ix == 0x7f800000) { /* x is +-inf */
if (hx < 0) {
if (iy >= 0x7f800000) {
F_RE(ans) = zero;
F_IM(ans) = zero;
} else {
sincosf(y, &s, &c);
F_RE(ans) = zero * c;
F_IM(ans) = zero * s;
}
} else {
if (iy >= 0x7f800000) {
F_RE(ans) = x;
F_IM(ans) = y - y;
} else {
sincosf(y, &s, &c);
F_RE(ans) = x * c;
F_IM(ans) = x * s;
}
}
} else {
sincosf(y, &s, &c);
if (ix >= 0x42B171AA) { /* |x| > 88.722... ~ log(2**128) */
#if defined(__i386) && !defined(__amd64)
int rp = __swapRP(fp_extended);
#endif
t = __k_cexp(x, &n);
F_RE(ans) = (float)scalbn(t * (double)c, n);
F_IM(ans) = (float)scalbn(t * (double)s, n);
#if defined(__i386) && !defined(__amd64)
if (rp != fp_extended)
(void) __swapRP(rp);
#endif
} else {
t = expf(x);
F_RE(ans) = t * c;
F_IM(ans) = t * s;
}
}
return (ans);
}示例4: log1p
double
log1p(double x)
{
static const double zero=0.0, negone= -1.0, one=1.0,
half=1.0/2.0, small=1.0E-20; /* 1+small == 1 */
double z,s,t,c;
int k;
if (isnan(x))
return (x);
if(finite(x)) {
if( x > negone ) {
/* argument reduction */
if(copysign(x,one)<small) return(x);
k=logb(one+x); z=scalbn(x,-k); t=scalbn(one,-k);
if(z+t >= sqrt2 )
{ k += 1 ; z *= half; t *= half; }
t += negone; x = z + t;
c = (t-x)+z ; /* correction term for x */
/* compute log(1+x) */
s = x/(2+x); t = x*x*half;
c += (k*ln2lo-c*x);
z = c+s*(t+__log__L(s*s));
x += (z - t) ;
return(k*ln2hi+x);
}
/* end of if (x > negone) */
else {
#if defined(__vax__)
if ( x == negone )
return (infnan(-ERANGE)); /* -INF */
else
return (infnan(EDOM)); /* NaN */
#else /* defined(__vax__) */
/* x = -1, return -INF with signal */
if ( x == negone ) return( negone/zero );
/* negative argument for log, return NaN with signal */
else return ( zero / zero );
#endif /* defined(__vax__) */
}
}
/* end of if (finite(x)) */
/* log(-INF) is NaN */
else if(x<0)
return(zero/zero);
/* log(+INF) is INF */
else return(x);
}示例5: normalize_value
inline T normalize_value(const T& val, const mpl::true_&)
{
BOOST_STATIC_ASSERT(std::numeric_limits<T>::is_specialized);
BOOST_STATIC_ASSERT(std::numeric_limits<T>::radix != 2);
boost::intmax_t shift = std::numeric_limits<T>::digits - ilogb(val) - 1;
T result = scalbn(val, shift);
result = round(result);
return scalbn(result, -shift);
}示例6: __ieee754_scalb
double attribute_hidden __ieee754_scalb(double x, double fn)
{
if (isnan(x)||isnan(fn)) return x*fn;
if (!isfinite(fn)) {
if(fn>0.0) return x*fn;
else return x/(-fn);
}
if (rint(fn)!=fn) return (fn-fn)/(fn-fn);
if ( fn > 65000.0) return scalbn(x, 65000);
if (-fn > 65000.0) return scalbn(x,-65000);
return scalbn(x,(int)fn);
}示例7: scalb
double
scalb(double x, double fn)
{
if (isnan(x)||isnan(fn)) return x*fn;
if (!finite(fn)) {
if(fn>0.0) return x*fn;
else return x/(-fn);
}
if (rint(fn)!=fn) return (fn-fn)/(fn-fn);
if ( fn > 65000.0) return scalbn(x, 65000);
if (-fn > 65000.0) return scalbn(x,-65000);
return scalbn(x,(int)fn);
}示例8: float2tms32
/*
* Convert a floating point number in native format to TMS32032
* floating point single precision (32 bit) format. Note that the
* TMS floating point value is returned as an unsigned integer.
*/
static unsigned int
float2tms32(float x)
{
unsigned int zero = 0x80000000; /* Zero value is special case */
int nfracbits = 23; /* Not including hidden bit / sign bit */
int signbit = 1 << nfracbits;
int fracmask = ~((~0)<<nfracbits);
int iexp;
int sign;
int ifrac;
unsigned int rtn;
if (x == 0){
rtn = zero;
}else{
iexp = ilogb(x); /* Binary exponent if 1 <= |fraction| < 2 */
ifrac = (int)scalbn(x, nfracbits-iexp); /* Frac part as integer */
if (x<0 && (ifrac & signbit)){
/* Force top bit of negative fraction to be 0 */
ifrac <<= 1;
iexp--;
}
sign = x<0 ? signbit : 0;
rtn = (iexp << (nfracbits+1)) | sign | (ifrac & fracmask);
}
return rtn;
}示例9: cosh
double
cosh(double x) {
double t, w;
w = fabs(x);
if (!finite(w))
return (w * w);
if (w < 0.3465) {
t = expm1(w);
w = 1.0 + t;
if (w != 1.0)
w = 1.0 + (t * t) / (w + w);
return (w);
} else if (w < 22.0) {
t = exp(w);
return (0.5 * (t + 1.0 / t));
} else if (w <= lnovft) {
return (0.5 * exp(w));
} else {
w = (w - 1024 * ln2hi) - 1024 * ln2lo;
if (w >= ln2)
return (_SVID_libm_err(x, x, 5));
else
return (scalbn(exp(w), 1023));
}
}示例10: ulp_imp
T ulp_imp(const T& val, const mpl::false_&, const Policy& pol)
{
BOOST_STATIC_ASSERT(std::numeric_limits<T>::is_specialized);
BOOST_STATIC_ASSERT(std::numeric_limits<T>::radix != 2);
BOOST_MATH_STD_USING
int expon;
static const char* function = "ulp<%1%>(%1%)";
int fpclass = (boost::math::fpclassify)(val);
if(fpclass == (int)FP_NAN)
{
return policies::raise_domain_error<T>(
function,
"Argument must be finite, but got %1%", val, pol);
}
else if((fpclass == (int)FP_INFINITE) || (fabs(val) >= tools::max_value<T>()))
{
return (val < 0 ? -1 : 1) * policies::raise_overflow_error<T>(function, 0, pol);
}
else if(fpclass == FP_ZERO)
return detail::get_smallest_value<T>();
//
// This code is almost the same as that for float_next, except for negative integers,
// where we preserve the relation ulp(x) == ulp(-x) as does Java:
//
expon = 1 + ilogb(fabs(val));
T diff = scalbn(T(1), expon - std::numeric_limits<T>::digits);
if(diff == 0)
diff = detail::get_smallest_value<T>();
return diff;
}示例11: vmod_hash_backend
vmod_hash_backend(const struct vrt_ctx *ctx, struct vmod_directors_hash *rr,
const char *arg, ...)
{
struct SHA256Context sha_ctx;
va_list ap;
const char *p;
unsigned char sha256[SHA256_LEN];
VCL_BACKEND be;
double r;
CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
CHECK_OBJ_NOTNULL(rr, VMOD_DIRECTORS_HASH_MAGIC);
SHA256_Init(&sha_ctx);
va_start(ap, arg);
p = arg;
while (p != vrt_magic_string_end) {
SHA256_Update(&sha_ctx, arg, strlen(arg));
p = va_arg(ap, const char *);
}
va_end(ap);
SHA256_Final(sha256, &sha_ctx);
r = vbe32dec(sha256);
r = scalbn(r, -32);
assert(r >= 0 && r <= 1.0);
be = vdir_pick_be(rr->vd, r, rr->nloops);
return (be);
}示例12: ldexp
double ldexp(double value, int exp)
{
if(!finite(value)||value==0.0) return value;
value = scalbn(value,exp);
if(!finite(value)||value==0.0) errno = ERANGE;
return value;
}示例13: ldexp
double ldexp(double value, int exp)
{
if(!finite(value)||value==0.0) return value;
value = scalbn(value,exp);
if(!finite(value)||value==0.0) libm_errno = 34;
return value;
}示例14: main
int main(void)
{
#pragma STDC FENV_ACCESS ON
double y;
float d;
int e, i, err = 0;
struct di_d *p;
for (i = 0; i < sizeof t/sizeof *t; i++) {
p = t + i;
if (p->r < 0)
continue;
fesetround(p->r);
feclearexcept(FE_ALL_EXCEPT);
y = scalbn(p->x, p->i);
e = fetestexcept(INEXACT|INVALID|DIVBYZERO|UNDERFLOW|OVERFLOW);
if (!checkexceptall(e, p->e, p->r)) {
printf("%s:%d: bad fp exception: %s scalbn(%a, %lld)=%a, want %s",
p->file, p->line, rstr(p->r), p->x, p->i, p->y, estr(p->e));
printf(" got %s\n", estr(e));
err++;
}
d = ulperr(y, p->y, p->dy);
if (!checkcr(y, p->y, p->r)) {
printf("%s:%d: %s scalbn(%a, %lld) want %a got %a, ulperr %.3f = %a + %a\n",
p->file, p->line, rstr(p->r), p->x, p->i, p->y, y, d, d-p->dy, p->dy);
err++;
}
}
return !!err;
}示例15: scalbln
double scalbln(double x, long n) {
if (n > INT_MAX)
n = INT_MAX;
else if (n < INT_MIN)
n = INT_MIN;
return scalbn(x, n);
}