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std.math.traits
This is a submodule of std.math.
It contains several functions for introspection on numerical values.
License:
Authors:
Walter Bright, Don Clugston,
Conversion of CEPHES math library to D by Iain Buclaw and David Nadlinger
Source std/math/traits.d
- pure nothrow @nogc @trusted bool
isNaN
(X)(Xx
)
if (isFloatingPoint!X); - Determines if x is NaN.Parameters:
X x
a floating point number. Returns:true if x is Nan.Examples:assert( isNaN(float.init)); assert( isNaN(-double.init)); assert( isNaN(real.nan)); assert( isNaN(-real.nan)); assert(!isNaN(cast(float) 53.6)); assert(!isNaN(cast(real)-53.6));
- pure nothrow @nogc @trusted bool
isFinite
(X)(Xx
); - Determines if x is finite.Parameters:
X x
a floating point number. Returns:true if x is finite.Examples:assert( isFinite(1.23f)); assert( isFinite(float.max)); assert( isFinite(float.min_normal)); assert(!isFinite(float.nan)); assert(!isFinite(float.infinity));
- pure nothrow @nogc @trusted bool
isNormal
(X)(Xx
); - Determines if x is normalized.A normalized number must not be zero, subnormal, infinite nor NAN.Parameters:
X x
a floating point number. Returns:true if x is normalized.Examples:float f = 3; double d = 500; real e = 10e+48; assert(isNormal(f)); assert(isNormal(d)); assert(isNormal(e)); f = d = e = 0; assert(!isNormal(f)); assert(!isNormal(d)); assert(!isNormal(e)); assert(!isNormal(real.infinity)); assert(isNormal(-real.max)); assert(!isNormal(real.min_normal/4));
- pure nothrow @nogc @trusted bool
isSubnormal
(X)(Xx
); - Determines if x is subnormal.Subnormals (also known as "denormal number"), have a 0 exponent and a 0 most significant mantissa bit.Parameters:
X x
a floating point number. Returns:true if x is a denormal number.Examples:import std.meta : AliasSeq; static foreach (T; AliasSeq!(float, double, real)) {{ T f; for (f = 1.0; !isSubnormal(f); f /= 2) assert(f != 0); }}
- pure nothrow @nogc @trusted bool
isInfinity
(X)(Xx
)
if (isFloatingPoint!X); - Determines if x is ±∞.Parameters:
X x
a floating point number. Returns:true if x is ±∞.Examples:assert(!isInfinity(float.init)); assert(!isInfinity(-float.init)); assert(!isInfinity(float.nan)); assert(!isInfinity(-float.nan)); assert(isInfinity(float.infinity)); assert(isInfinity(-float.infinity)); assert(isInfinity(-1.0f / 0.0f));
- pure nothrow @nogc @trusted bool
isIdentical
(realx
, realy
); - Is the binary representation of x identical to y?Examples:
assert( isIdentical(0.0, 0.0)); assert( isIdentical(1.0, 1.0)); assert( isIdentical(real.infinity, real.infinity)); assert( isIdentical(-real.infinity, -real.infinity)); assert(!isIdentical(0.0, -0.0)); assert(!isIdentical(real.nan, -real.nan)); assert(!isIdentical(real.infinity, -real.infinity));
- pure nothrow @nogc @trusted int
signbit
(X)(Xx
); - Return 1 if sign bit of e is set, 0 if not.Examples:
assert(!signbit(float.nan)); assert(signbit(-float.nan)); assert(!signbit(168.1234f)); assert(signbit(-168.1234f)); assert(!signbit(0.0f)); assert(signbit(-0.0f)); assert(signbit(-float.max)); assert(!signbit(float.max)); assert(!signbit(double.nan)); assert(signbit(-double.nan)); assert(!signbit(168.1234)); assert(signbit(-168.1234)); assert(!signbit(0.0)); assert(signbit(-0.0)); assert(signbit(-double.max)); assert(!signbit(double.max)); assert(!signbit(real.nan)); assert(signbit(-real.nan)); assert(!signbit(168.1234L)); assert(signbit(-168.1234L)); assert(!signbit(0.0L)); assert(signbit(-0.0L)); assert(signbit(-real.max)); assert(!signbit(real.max));
- pure nothrow @nogc @trusted R
copysign
(R, X)(Rto
, Xfrom
)
if (isFloatingPoint!R && isFloatingPoint!X);
pure nothrow @nogc @trusted Rcopysign
(R, X)(Xto
, Rfrom
)
if (isIntegral!X && isFloatingPoint!R); - Parameters:
R to
the numeric value to use X from
the sign value to use Returns:a value composed of to with from's sign bit.Examples:writeln(copysign(1.0, 1.0)); // 1.0 writeln(copysign(1.0, -0.0)); // -1.0 writeln(copysign(1UL, -1.0)); // -1.0 writeln(copysign(-1.0, -1.0)); // -1.0 writeln(copysign(real.infinity, -1.0)); // -real.infinity assert(copysign(real.nan, 1.0) is real.nan); assert(copysign(-real.nan, 1.0) is real.nan); assert(copysign(real.nan, -1.0) is -real.nan);
- pure nothrow @nogc @safe F
sgn
(F)(Fx
)
if (isFloatingPoint!F || isIntegral!F); - Returns -1 if x < 0,
x
if x == 0, 1 if x > 0, and NAN if x==NAN.Examples:writeln(sgn(168.1234)); // 1 writeln(sgn(-168.1234)); // -1 writeln(sgn(0.0)); // 0 writeln(sgn(-0.0)); // 0
- pure nothrow @nogc @safe bool
isPowerOf2
(X)(const Xx
)
if (isNumeric!X); - Check whether a number is an integer power of two.Note that only positive numbers can be integer powers of two. This function always return false if
x
is negative or zero.Parameters:X x
the number to test Returns:true ifx
is an integer power of two.Examples:import std.math.exponential : pow; assert( isPowerOf2(1.0L)); assert( isPowerOf2(2.0L)); assert( isPowerOf2(0.5L)); assert( isPowerOf2(pow(2.0L, 96))); assert( isPowerOf2(pow(2.0L, -77))); assert(!isPowerOf2(-2.0L)); assert(!isPowerOf2(-0.5L)); assert(!isPowerOf2(0.0L)); assert(!isPowerOf2(4.315)); assert(!isPowerOf2(1.0L / 3.0L)); assert(!isPowerOf2(real.nan)); assert(!isPowerOf2(real.infinity));
Examples:assert( isPowerOf2(1)); assert( isPowerOf2(2)); assert( isPowerOf2(1uL << 63)); assert(!isPowerOf2(-4)); assert(!isPowerOf2(0)); assert(!isPowerOf2(1337u));
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