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gnu/gcc/6924bcee14bdcecf0fcb6764f546dd7ca8ca8f9a/./libphobos/libdruntime/core/math.d
blob: 941b5de3c4efa1f4323a5723eeb952ef7e9ccd06 [file]
// Written in the D programming language.
/**
* Builtin mathematical intrinsics
*
* Source: $(DRUNTIMESRC core/_math.d)
* Macros:
* TABLE_SV = <table border="1" cellpadding="4" cellspacing="0">
* <caption>Special Values</caption>
* $0</table>
*
* NAN = $(RED NAN)
* SUP = <span style="vertical-align:super;font-size:smaller">$0</span>
* POWER = $1<sup>$2</sup>
* PLUSMN = &plusmn;
* INFIN = &infin;
* PLUSMNINF = &plusmn;&infin;
* LT = &lt;
* GT = &gt;
*
* Copyright: Copyright Digital Mars 2000 - 2011.
* License: $(HTTP www.boost.org/LICENSE_1_0.txt, Boost License 1.0).
* Authors: $(HTTP digitalmars.com, Walter Bright),
* Don Clugston
*/
module core.math;
public:
@nogc:
nothrow:
@safe:
pure:
/***********************************
* Returns cosine of x. x is in radians.
*
* $(TABLE_SV
* $(TR $(TH x) $(TH cos(x)) $(TH invalid?))
* $(TR $(TD $(NAN)) $(TD $(NAN)) $(TD yes) )
* $(TR $(TD $(PLUSMN)$(INFIN)) $(TD $(NAN)) $(TD yes) )
* )
* Bugs:
* Results are undefined if |x| >= $(POWER 2,64).
*/
float cos(float x); /* intrinsic */
double cos(double x); /* intrinsic */ /// ditto
real cos(real x); /* intrinsic */ /// ditto
/***********************************
* Returns sine of x. x is in radians.
*
* $(TABLE_SV
* $(TR $(TH x) $(TH sin(x)) $(TH invalid?))
* $(TR $(TD $(NAN)) $(TD $(NAN)) $(TD yes))
* $(TR $(TD $(PLUSMN)0.0) $(TD $(PLUSMN)0.0) $(TD no))
* $(TR $(TD $(PLUSMNINF)) $(TD $(NAN)) $(TD yes))
* )
* Bugs:
* Results are undefined if |x| >= $(POWER 2,64).
*/
float sin(float x); /* intrinsic */
double sin(double x); /* intrinsic */ /// ditto
real sin(real x); /* intrinsic */ /// ditto
/*****************************************
* Returns x rounded to a long value using the current rounding mode.
* If the integer value of x is
* greater than long.max, the result is
* indeterminate.
*/
long rndtol(float x); /* intrinsic */
long rndtol(double x); /* intrinsic */ /// ditto
long rndtol(real x); /* intrinsic */ /// ditto
/***************************************
* Compute square root of x.
*
* $(TABLE_SV
* $(TR $(TH x) $(TH sqrt(x)) $(TH invalid?))
* $(TR $(TD -0.0) $(TD -0.0) $(TD no))
* $(TR $(TD $(LT)0.0) $(TD $(NAN)) $(TD yes))
* $(TR $(TD +$(INFIN)) $(TD +$(INFIN)) $(TD no))
* )
*/
float sqrt(float x); /* intrinsic */
double sqrt(double x); /* intrinsic */ /// ditto
real sqrt(real x); /* intrinsic */ /// ditto
/*******************************************
* Compute n * 2$(SUPERSCRIPT exp)
* References: frexp
*/
float ldexp(float n, int exp); /* intrinsic */
double ldexp(double n, int exp); /* intrinsic */ /// ditto
real ldexp(real n, int exp); /* intrinsic */ /// ditto
unittest {
static if (real.mant_dig == 113)
{
assert(ldexp(1.0L, -16384) == 0x1p-16384L);
assert(ldexp(1.0L, -16382) == 0x1p-16382L);
}
else static if (real.mant_dig == 106)
{
assert(ldexp(1.0L, 1023) == 0x1p1023L);
assert(ldexp(1.0L, -1022) == 0x1p-1022L);
assert(ldexp(1.0L, -1021) == 0x1p-1021L);
}
else static if (real.mant_dig == 64)
{
assert(ldexp(1.0L, -16384) == 0x1p-16384L);
assert(ldexp(1.0L, -16382) == 0x1p-16382L);
}
else static if (real.mant_dig == 53)
{
assert(ldexp(1.0L, 1023) == 0x1p1023L);
assert(ldexp(1.0L, -1022) == 0x1p-1022L);
assert(ldexp(1.0L, -1021) == 0x1p-1021L);
}
else
assert(false, "Only 128bit, 80bit and 64bit reals expected here");
}
/*******************************
* Compute the absolute value.
* $(TABLE_SV
* $(TR $(TH x) $(TH fabs(x)))
* $(TR $(TD $(PLUSMN)0.0) $(TD +0.0) )
* $(TR $(TD $(PLUSMN)$(INFIN)) $(TD +$(INFIN)) )
* )
* It is implemented as a compiler intrinsic.
* Params:
* x = floating point value
* Returns: |x|
* References: equivalent to `std.math.fabs`
*/
@safe pure nothrow @nogc
{
float fabs(float x);
double fabs(double x); /// ditto
real fabs(real x); /// ditto
}
/**********************************
* Rounds x to the nearest integer value, using the current rounding
* mode.
* If the return value is not equal to x, the FE_INEXACT
* exception is raised.
* $(B nearbyint) performs
* the same operation, but does not set the FE_INEXACT exception.
*/
float rint(float x); /* intrinsic */
double rint(double x); /* intrinsic */ /// ditto
real rint(real x); /* intrinsic */ /// ditto
/***********************************
* Building block functions, they
* translate to a single x87 instruction.
*/
// y * log2(x)
float yl2x(float x, float y); /* intrinsic */
double yl2x(double x, double y); /* intrinsic */ /// ditto
real yl2x(real x, real y); /* intrinsic */ /// ditto
// y * log2(x +1)
float yl2xp1(float x, float y); /* intrinsic */
double yl2xp1(double x, double y); /* intrinsic */ /// ditto
real yl2xp1(real x, real y); /* intrinsic */ /// ditto
unittest
{
version (INLINE_YL2X)
{
assert(yl2x(1024.0L, 1) == 10);
assert(yl2xp1(1023.0L, 1) == 10);
}
}
/*************************************
* Round argument to a specific precision.
*
* D language types specify only a minimum precision, not a maximum. The
* `toPrec()` function forces rounding of the argument `f` to the precision
* of the specified floating point type `T`.
* The rounding mode used is inevitably target-dependent, but will be done in
* a way to maximize accuracy. In most cases, the default is round-to-nearest.
*
* Params:
* T = precision type to round to
* f = value to convert
* Returns:
* f in precision of type `T`
*/
T toPrec(T:float)(float f) { pragma(inline, false); return f; }
/// ditto
T toPrec(T:float)(double f) { pragma(inline, false); return cast(T) f; }
/// ditto
T toPrec(T:float)(real f) { pragma(inline, false); return cast(T) f; }
/// ditto
T toPrec(T:double)(float f) { pragma(inline, false); return f; }
/// ditto
T toPrec(T:double)(double f) { pragma(inline, false); return f; }
/// ditto
T toPrec(T:double)(real f) { pragma(inline, false); return cast(T) f; }
/// ditto
T toPrec(T:real)(float f) { pragma(inline, false); return f; }
/// ditto
T toPrec(T:real)(double f) { pragma(inline, false); return f; }
/// ditto
T toPrec(T:real)(real f) { pragma(inline, false); return f; }
@safe unittest
{
// Test all instantiations work with all combinations of float.
float f = 1.1f;
double d = 1.1;
real r = 1.1L;
f = toPrec!float(f + f);
f = toPrec!float(d + d);
f = toPrec!float(r + r);
d = toPrec!double(f + f);
d = toPrec!double(d + d);
d = toPrec!double(r + r);
r = toPrec!real(f + f);
r = toPrec!real(d + d);
r = toPrec!real(r + r);
// Comparison tests.
bool approxEqual(T)(T lhs, T rhs)
{
return fabs((lhs - rhs) / rhs) <= 1e-2 || fabs(lhs - rhs) <= 1e-5;
}
enum real PIR = 0xc.90fdaa22168c235p-2;
enum double PID = 0x1.921fb54442d18p+1;
enum float PIF = 0x1.921fb6p+1;
static assert(approxEqual(toPrec!float(PIR), PIF));
static assert(approxEqual(toPrec!double(PIR), PID));
static assert(approxEqual(toPrec!real(PIR), PIR));
static assert(approxEqual(toPrec!float(PID), PIF));
static assert(approxEqual(toPrec!double(PID), PID));
static assert(approxEqual(toPrec!real(PID), PID));
static assert(approxEqual(toPrec!float(PIF), PIF));
static assert(approxEqual(toPrec!double(PIF), PIF));
static assert(approxEqual(toPrec!real(PIF), PIF));
assert(approxEqual(toPrec!float(PIR), PIF));
assert(approxEqual(toPrec!double(PIR), PID));
assert(approxEqual(toPrec!real(PIR), PIR));
assert(approxEqual(toPrec!float(PID), PIF));
assert(approxEqual(toPrec!double(PID), PID));
assert(approxEqual(toPrec!real(PID), PID));
assert(approxEqual(toPrec!float(PIF), PIF));
assert(approxEqual(toPrec!double(PIF), PIF));
assert(approxEqual(toPrec!real(PIF), PIF));
}