Add docs and tests for fp classificators
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@ -1,304 +0,0 @@
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/**
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* Copyright: Eugene Wissner 2017.
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* License: $(LINK2 https://www.mozilla.org/en-US/MPL/2.0/,
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* Mozilla Public License, v. 2.0).
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* Authors: $(LINK2 mailto:info@caraus.de, Eugene Wissner)
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* Source: $(LINK2 https://github.com/caraus-ecms/tanya/blob/master/source/tanya/math/fp.d,
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* tanya/math/fp.d)
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*/
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module tanya.math.fp;
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import tanya.math.nbtheory;
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/**
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* Floating-point number precisions according to IEEE-754.
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*/
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enum IEEEPrecision : ubyte
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{
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/// Single precision: 64-bit.
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single = 4,
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/// Single precision: 64-bit.
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double_ = 8,
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/// Extended precision: 80-bit.
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extended = 10,
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}
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/**
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* Tests the precision of floating-point type $(D_PARAM F).
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*
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* For $(D_KEYWORD float), $(D_PSYMBOL ieeePrecision) always evaluates to
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* $(D_INLINECODE IEEEPrecision.single); for $(D_KEYWORD double) - to
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* $(D_INLINECODE IEEEPrecision.double). It returns different values only
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* for $(D_KEYWORD real), since $(D_KEYWORD real) is a platform-dependent type.
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*
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* If $(D_PARAM F) is a $(D_KEYWORD real) and the target platform isn't
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* currently supported, static assertion error will be raised (you can use
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* $(D_INLINECODE is(typeof(ieeePrecision!F))) for testing the platform support
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* without a compilation error).
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*
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* Params:
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* F = Type to be tested.
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*
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* Returns: Precision according to IEEE-754.
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*
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* See_Also: $(D_PSYMBOL IEEEPrecision).
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*/
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template ieeePrecision(F)
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if (isFloatingPoint!F)
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{
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static if (F.sizeof == float.sizeof)
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{
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enum IEEEPrecision ieeePrecision = IEEEPrecision.single;
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}
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else static if (F.sizeof == double.sizeof)
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{
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enum IEEEPrecision ieeePrecision = IEEEPrecision.double_;
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}
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else version (X86)
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{
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enum IEEEPrecision ieeePrecision = IEEEPrecision.extended;
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}
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else version (X86_64)
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{
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enum IEEEPrecision ieeePrecision = IEEEPrecision.extended;
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}
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else
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{
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static assert(false, "Unsupported IEEE 754 floating point precision");
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}
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}
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private union FloatBits(F)
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{
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F floating;
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static if (ieeePrecision!F == IEEEPrecision.single)
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{
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uint integral;
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}
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else static if (ieeePrecision!F == IEEEPrecision.double_)
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{
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ulong integral;
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}
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else static if (ieeePrecision!F == IEEEPrecision.extended)
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{
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struct // Little-endian.
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{
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ulong mantissa;
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ushort exp;
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}
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}
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else
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{
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static assert(false, "Unsupported IEEE 754 floating point precision");
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}
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}
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enum FloatingPointClass : ubyte
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{
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nan,
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zero,
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infinite,
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subnormal,
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normal,
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}
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FloatingPointClass classify(F)(F x)
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if (isFloatingPoint!F)
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{
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if (x == 0)
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{
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return FloatingPointClass.zero;
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}
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FloatBits!F bits;
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bits.floating = abs(x);
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static if (ieeePrecision!F == IEEEPrecision.single)
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{
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if (bits.integral > 0x7f800000)
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{
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return FloatingPointClass.nan;
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}
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else if (bits.integral == 0x7f800000)
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{
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return FloatingPointClass.infinite;
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}
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else if (bits.integral < 0x800000)
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{
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return FloatingPointClass.subnormal;
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}
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}
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else static if (ieeePrecision!F == IEEEPrecision.double_)
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{
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if (bits.integral > 0x7ff0000000000000)
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{
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return FloatingPointClass.nan;
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}
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else if (bits.integral == 0x7ff0000000000000)
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{
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return FloatingPointClass.infinite;
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}
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else if (bits.integral < 0x10000000000000)
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{
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return FloatingPointClass.subnormal;
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}
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}
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else static if (ieeePrecision!F == IEEEPrecision.extended)
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{
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if (bits.exp == 0x7fff)
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{
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if ((bits.mantissa & 0x7fffffffffffffff) == 0)
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{
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return FloatingPointClass.infinite;
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}
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else
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{
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return FloatingPointClass.nan;
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}
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}
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else if (bits.exp == 0)
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{
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return FloatingPointClass.subnormal;
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}
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else if (bits.mantissa < 0x8000000000000000) // "Unnormal".
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{
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return FloatingPointClass.nan;
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}
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}
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return FloatingPointClass.normal;
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}
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bool isFinite(F)(F x)
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if (isFloatingPoint!F)
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{
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FloatBits!F bits;
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static if (ieeePrecision!F == IEEEPrecision.single)
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{
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bits.floating = x;
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bits.integral &= 0x7f800000;
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return bits.integral != 0x7f800000;
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}
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else static if (ieeePrecision!F == IEEEPrecision.double_)
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{
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bits.floating = x;
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bits.integral &= 0x7ff0000000000000;
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return bits.integral != 0x7ff0000000000000;
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}
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else static if (ieeePrecision!F == IEEEPrecision.extended)
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{
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bits.floating = abs(x);
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return (bits.exp != 0x7fff) && (bits.mantissa >= 0x8000000000000000);
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}
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}
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bool isNaN(F)(F x)
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if (isFloatingPoint!F)
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{
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FloatBits!F bits;
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bits.floating = abs(x);
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static if (ieeePrecision!F == IEEEPrecision.single)
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{
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return bits.integral > 0x7f800000;
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}
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else static if (ieeePrecision!F == IEEEPrecision.double_)
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{
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return bits.integral > 0x7ff0000000000000;
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}
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else static if (ieeePrecision!F == IEEEPrecision.extended)
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{
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if ((bits.exp == 0x7fff && (bits.mantissa & 0x7fffffffffffffff) != 0)
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|| ((bits.exp != 0) && (bits.mantissa < 0x8000000000000000)))
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{
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return true;
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}
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return false;
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}
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}
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bool isInfinity(F)(F x)
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if (isFloatingPoint!F)
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{
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FloatBits!F bits;
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bits.floating = abs(x);
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static if (ieeePrecision!F == IEEEPrecision.single)
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{
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return bits.integral == 0x7f800000;
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}
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else static if (ieeePrecision!F == IEEEPrecision.double_)
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{
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return bits.integral == 0x7ff0000000000000;
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}
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else static if (ieeePrecision!F == IEEEPrecision.extended)
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{
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return (bits.exp == 0x7fff)
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&& ((bits.mantissa & 0x7fffffffffffffff) == 0);
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}
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}
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bool isSubnormal(F)(F x)
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if (isFloatingPoint!F)
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{
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FloatBits!F bits;
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bits.floating = abs(x);
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static if (ieeePrecision!F == IEEEPrecision.single)
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{
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return bits.integral < 0x800000;
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}
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else static if (ieeePrecision!F == IEEEPrecision.double_)
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{
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return bits.integral < 0x10000000000000;
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}
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else static if (ieeePrecision!F == IEEEPrecision.extended)
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{
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return bits.exp == 0;
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}
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}
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bool isNormal(F)(F x)
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if (isFloatingPoint!F)
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{
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static if (ieeePrecision!F == IEEEPrecision.single)
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{
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FloatBits!F bits;
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bits.floating = x;
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bits.integral &= 0x7f800000;
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return bits.integral != 0 && bits.integral != 0x7f800000;
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}
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else static if (ieeePrecision!F == IEEEPrecision.double_)
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{
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FloatBits!F bits;
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bits.floating = x;
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bits.integral &= 0x7ff0000000000000;
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return bits.integral != 0 && bits.integral != 0x7ff0000000000000;
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}
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else static if (ieeePrecision!F == IEEEPrecision.extended)
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{
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return classify(x) == FloatingPointClass.normal;
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}
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}
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bool signBit(F)(F x)
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if (isFloatingPoint!F)
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{
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FloatBits!F bits;
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bits.floating = x;
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static if (ieeePrecision!F == IEEEPrecision.single)
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{
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return (bits.integral & (1 << 31)) != 0;
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}
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else static if (ieeePrecision!F == IEEEPrecision.double_)
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{
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return (bits.integral & (1 << 63)) != 0;
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}
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else static if (ieeePrecision!F == IEEEPrecision.extended)
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{
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return (bits.exp & (1 << 15)) != 0;
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}
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}
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@ -19,6 +19,540 @@ public import tanya.math.nbtheory;
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public import tanya.math.random;
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import tanya.meta.trait;
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/// Floating-point number precisions according to IEEE-754.
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enum IEEEPrecision : ubyte
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{
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single = 4, /// Single precision: 64-bit.
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double_ = 8, /// Single precision: 64-bit.
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doubleExtended = 10, /// Double extended precision: 80-bit.
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}
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/**
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* Tests the precision of floating-point type $(D_PARAM F).
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*
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* For $(D_KEYWORD float), $(D_PSYMBOL ieeePrecision) always evaluates to
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* $(D_INLINECODE IEEEPrecision.single); for $(D_KEYWORD double) - to
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* $(D_INLINECODE IEEEPrecision.double). It returns different values only
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* for $(D_KEYWORD real), since $(D_KEYWORD real) is a platform-dependent type.
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*
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* If $(D_PARAM F) is a $(D_KEYWORD real) and the target platform isn't
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* currently supported, static assertion error will be raised (you can use
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* $(D_INLINECODE is(typeof(ieeePrecision!F))) for testing the platform support
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* without a compilation error).
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*
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* Params:
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* F = Type to be tested.
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*
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* Returns: Precision according to IEEE-754.
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*
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* See_Also: $(D_PSYMBOL IEEEPrecision).
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*/
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template ieeePrecision(F)
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if (isFloatingPoint!F)
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{
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static if (F.sizeof == float.sizeof)
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{
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enum IEEEPrecision ieeePrecision = IEEEPrecision.single;
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}
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else static if (F.sizeof == double.sizeof)
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{
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enum IEEEPrecision ieeePrecision = IEEEPrecision.double_;
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}
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else version (X86)
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{
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enum IEEEPrecision ieeePrecision = IEEEPrecision.doubleExtended;
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}
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else version (X86_64)
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{
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enum IEEEPrecision ieeePrecision = IEEEPrecision.doubleExtended;
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}
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else
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{
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static assert(false, "Unsupported IEEE 754 floating point precision");
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}
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}
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///
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pure nothrow @safe @nogc unittest
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{
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static assert(ieeePrecision!float == IEEEPrecision.single);
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static assert(ieeePrecision!double == IEEEPrecision.double_);
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}
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private union FloatBits(F)
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{
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F floating;
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static if (ieeePrecision!F == IEEEPrecision.single)
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{
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uint integral;
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enum uint expMask = 0x7f800000;
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}
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else static if (ieeePrecision!F == IEEEPrecision.double_)
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{
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ulong integral;
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enum ulong expMask = 0x7ff0000000000000;
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}
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else static if (ieeePrecision!F == IEEEPrecision.doubleExtended)
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{
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struct // Little-endian.
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{
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ulong mantissa;
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ushort exp;
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}
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enum ulong mantissaMask = 0x7fffffffffffffff;
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enum uint expMask = 0x7fff;
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}
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else
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{
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static assert(false, "Unsupported IEEE 754 floating point precision");
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}
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}
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/**
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* Floating-point number classifications.
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*/
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enum FloatingPointClass : ubyte
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{
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/**
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* Not a Number.
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*
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* See_Also: $(D_PSYMBOL isNaN).
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*/
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nan,
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/// Zero.
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zero,
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/**
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* Infinity.
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*
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* See_Also: $(D_PSYMBOL isInfinity).
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*/
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infinite,
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/**
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* Denormalized number.
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*
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* See_Also: $(D_PSYMBOL isSubnormal).
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*/
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subnormal,
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/**
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* Normalized number.
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*
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* See_Also: $(D_PSYMBOL isNormal).
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*/
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normal,
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}
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/**
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* Returns whether $(D_PARAM x) is a NaN, zero, infinity, subnormal or
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* normalized number.
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*
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* This function doesn't distinguish between negative and positive infinity,
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* negative and positive NaN or negative and positive zero.
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*
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* Params:
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* F = Type of the floating point number.
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* x = Floating point number.
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*
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* Returns: Classification of $(D_PARAM x).
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*/
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FloatingPointClass classify(F)(F x)
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if (isFloatingPoint!F)
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{
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if (x == 0)
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{
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return FloatingPointClass.zero;
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}
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FloatBits!F bits;
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bits.floating = abs(x);
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static if (ieeePrecision!F == IEEEPrecision.single)
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{
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if (bits.integral > bits.expMask)
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{
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return FloatingPointClass.nan;
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}
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else if (bits.integral == bits.expMask)
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{
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return FloatingPointClass.infinite;
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}
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else if (bits.integral < (1 << 23))
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{
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return FloatingPointClass.subnormal;
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}
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}
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else static if (ieeePrecision!F == IEEEPrecision.double_)
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{
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if (bits.integral > bits.expMask)
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{
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return FloatingPointClass.nan;
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}
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else if (bits.integral == bits.expMask)
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{
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return FloatingPointClass.infinite;
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}
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else if (bits.integral < (1L << 52))
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{
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return FloatingPointClass.subnormal;
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}
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}
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else static if (ieeePrecision!F == IEEEPrecision.doubleExtended)
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{
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if (bits.exp == bits.expMask)
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{
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if ((bits.mantissa & bits.mantissaMask) == 0)
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{
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return FloatingPointClass.infinite;
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}
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else
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{
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return FloatingPointClass.nan;
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}
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}
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else if (bits.exp == 0)
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{
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return FloatingPointClass.subnormal;
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}
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else if (bits.mantissa < (1L << 63)) // "Unnormal".
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{
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return FloatingPointClass.nan;
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}
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}
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return FloatingPointClass.normal;
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}
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///
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pure nothrow @safe @nogc unittest
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{
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assert(classify(0.0) == FloatingPointClass.zero);
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assert(classify(double.nan) == FloatingPointClass.nan);
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assert(classify(double.infinity) == FloatingPointClass.infinite);
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assert(classify(-double.infinity) == FloatingPointClass.infinite);
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assert(classify(1.4) == FloatingPointClass.normal);
|
||||
assert(classify(1.11254e-307 / 10) == FloatingPointClass.subnormal);
|
||||
|
||||
assert(classify(0.0f) == FloatingPointClass.zero);
|
||||
assert(classify(float.nan) == FloatingPointClass.nan);
|
||||
assert(classify(float.infinity) == FloatingPointClass.infinite);
|
||||
assert(classify(-float.infinity) == FloatingPointClass.infinite);
|
||||
assert(classify(0.3) == FloatingPointClass.normal);
|
||||
assert(classify(5.87747e-38f / 10) == FloatingPointClass.subnormal);
|
||||
|
||||
assert(classify(0.0L) == FloatingPointClass.zero);
|
||||
assert(classify(real.nan) == FloatingPointClass.nan);
|
||||
assert(classify(real.infinity) == FloatingPointClass.infinite);
|
||||
assert(classify(-real.infinity) == FloatingPointClass.infinite);
|
||||
}
|
||||
|
||||
private pure nothrow @nogc @safe unittest
|
||||
{
|
||||
static if (ieeePrecision!float == IEEEPrecision.doubleExtended)
|
||||
{
|
||||
assert(classify(1.68105e-10) == FloatingPointClass.normal);
|
||||
assert(classify(1.68105e-4932L) == FloatingPointClass.subnormal);
|
||||
|
||||
// Emulate unnormals, because they aren't generated anymore since i386
|
||||
FloatBits!real unnormal;
|
||||
unnormal.exp = 0x123;
|
||||
unnormal.mantissa = 0x1;
|
||||
assert(classify(unnormal) == FloatingPointClass.subnormal);
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Determines whether $(D_PARAM x) is a finite number.
|
||||
*
|
||||
* Params:
|
||||
* F = Type of the floating point number.
|
||||
* x = Floating point number.
|
||||
*
|
||||
* Returns: $(D_KEYWORD true) if $(D_PARAM x) is a finite number,
|
||||
* $(D_KEYWORD false) otherwise.
|
||||
*
|
||||
* See_Also: $(D_PSYMBOL isInfinity).
|
||||
*/
|
||||
bool isFinite(F)(F x)
|
||||
if (isFloatingPoint!F)
|
||||
{
|
||||
FloatBits!F bits;
|
||||
static if (ieeePrecision!F == IEEEPrecision.single
|
||||
|| ieeePrecision!F == IEEEPrecision.double_)
|
||||
{
|
||||
bits.floating = x;
|
||||
bits.integral &= bits.expMask;
|
||||
return bits.integral != bits.expMask;
|
||||
}
|
||||
else static if (ieeePrecision!F == IEEEPrecision.doubleExtended)
|
||||
{
|
||||
bits.floating = abs(x);
|
||||
return (bits.exp != bits.expMask)
|
||||
&& (bits.exp == 0 || bits.mantissa >= (1L << 63));
|
||||
}
|
||||
}
|
||||
|
||||
///
|
||||
pure nothrow @safe @nogc unittest
|
||||
{
|
||||
assert(!isFinite(float.infinity));
|
||||
assert(!isFinite(-double.infinity));
|
||||
assert(isFinite(0.0));
|
||||
assert(!isFinite(float.nan));
|
||||
assert(isFinite(5.87747e-38f / 10));
|
||||
assert(isFinite(1.11254e-307 / 10));
|
||||
assert(isFinite(0.5));
|
||||
}
|
||||
|
||||
/**
|
||||
* Determines whether $(D_PARAM x) is $(B n)ot $(B a) $(B n)umber (NaN).
|
||||
*
|
||||
* Params:
|
||||
* F = Type of the floating point number.
|
||||
* x = Floating point number.
|
||||
*
|
||||
* Returns: $(D_KEYWORD true) if $(D_PARAM x) is not a number,
|
||||
* $(D_KEYWORD false) otherwise.
|
||||
*/
|
||||
bool isNaN(F)(F x)
|
||||
if (isFloatingPoint!F)
|
||||
{
|
||||
FloatBits!F bits;
|
||||
bits.floating = abs(x);
|
||||
|
||||
static if (ieeePrecision!F == IEEEPrecision.single
|
||||
|| ieeePrecision!F == IEEEPrecision.double_)
|
||||
{
|
||||
return bits.integral > bits.expMask;
|
||||
}
|
||||
else static if (ieeePrecision!F == IEEEPrecision.doubleExtended)
|
||||
{
|
||||
const maskedMantissa = bits.mantissa & bits.mantissaMask;
|
||||
if ((bits.exp == bits.expMask && maskedMantissa != 0)
|
||||
|| ((bits.exp != 0) && (bits.mantissa < (1L << 63))))
|
||||
{
|
||||
return true;
|
||||
}
|
||||
return false;
|
||||
}
|
||||
}
|
||||
|
||||
///
|
||||
pure nothrow @safe @nogc unittest
|
||||
{
|
||||
assert(isNaN(float.init));
|
||||
assert(isNaN(double.init));
|
||||
assert(isNaN(real.init));
|
||||
}
|
||||
|
||||
/**
|
||||
* Determines whether $(D_PARAM x) is a positive or negative infinity.
|
||||
*
|
||||
* Params:
|
||||
* F = Type of the floating point number.
|
||||
* x = Floating point number.
|
||||
*
|
||||
* Returns: $(D_KEYWORD true) if $(D_PARAM x) is infinity, $(D_KEYWORD false)
|
||||
* otherwise.
|
||||
*
|
||||
* See_Also: $(D_PSYMBOL isFinite).
|
||||
*/
|
||||
bool isInfinity(F)(F x)
|
||||
if (isFloatingPoint!F)
|
||||
{
|
||||
FloatBits!F bits;
|
||||
bits.floating = abs(x);
|
||||
static if (ieeePrecision!F == IEEEPrecision.single
|
||||
|| ieeePrecision!F == IEEEPrecision.double_)
|
||||
{
|
||||
return bits.integral == bits.expMask;
|
||||
}
|
||||
else static if (ieeePrecision!F == IEEEPrecision.doubleExtended)
|
||||
{
|
||||
return (bits.exp == bits.expMask)
|
||||
&& ((bits.mantissa & bits.mantissaMask) == 0);
|
||||
}
|
||||
}
|
||||
|
||||
///
|
||||
pure nothrow @safe @nogc unittest
|
||||
{
|
||||
assert(isInfinity(float.infinity));
|
||||
assert(isInfinity(-float.infinity));
|
||||
assert(isInfinity(double.infinity));
|
||||
assert(isInfinity(-double.infinity));
|
||||
assert(isInfinity(real.infinity));
|
||||
assert(isInfinity(-real.infinity));
|
||||
}
|
||||
|
||||
/**
|
||||
* Determines whether $(D_PARAM x) is a denormilized number or not.
|
||||
|
||||
* Denormalized number is a number between `0` and `1` that cannot be
|
||||
* represented as
|
||||
*
|
||||
* <pre>
|
||||
* m*2<sup>e</sup>
|
||||
* </pre>
|
||||
*
|
||||
* where $(I m) is the mantissa and $(I e) is an exponent that fits into the
|
||||
* exponent field of the type $(D_PARAM F).
|
||||
*
|
||||
* `0` is neither normalized nor denormalized.
|
||||
*
|
||||
* Params:
|
||||
* F = Type of the floating point number.
|
||||
* x = Floating point number.
|
||||
*
|
||||
* Returns: $(D_KEYWORD true) if $(D_PARAM x) is a denormilized number,
|
||||
* $(D_KEYWORD false) otherwise.
|
||||
*
|
||||
* See_Also: $(D_PSYMBOL isNormal).
|
||||
*/
|
||||
bool isSubnormal(F)(F x)
|
||||
if (isFloatingPoint!F)
|
||||
{
|
||||
FloatBits!F bits;
|
||||
bits.floating = abs(x);
|
||||
static if (ieeePrecision!F == IEEEPrecision.single)
|
||||
{
|
||||
return bits.integral < (1 << 23) && bits.integral > 0;
|
||||
}
|
||||
else static if (ieeePrecision!F == IEEEPrecision.double_)
|
||||
{
|
||||
return bits.integral < (1L << 52) && bits.integral > 0;
|
||||
}
|
||||
else static if (ieeePrecision!F == IEEEPrecision.doubleExtended)
|
||||
{
|
||||
return bits.exp == 0 && bits.mantissa != 0;
|
||||
}
|
||||
}
|
||||
|
||||
///
|
||||
pure nothrow @safe @nogc unittest
|
||||
{
|
||||
assert(!isSubnormal(0.0f));
|
||||
assert(!isSubnormal(float.nan));
|
||||
assert(!isSubnormal(float.infinity));
|
||||
assert(!isSubnormal(0.3f));
|
||||
assert(isSubnormal(5.87747e-38f / 10));
|
||||
|
||||
assert(!isSubnormal(0.0));
|
||||
assert(!isSubnormal(double.nan));
|
||||
assert(!isSubnormal(double.infinity));
|
||||
assert(!isSubnormal(1.4));
|
||||
assert(isSubnormal(1.11254e-307 / 10));
|
||||
|
||||
assert(!isSubnormal(0.0L));
|
||||
assert(!isSubnormal(real.nan));
|
||||
assert(!isSubnormal(real.infinity));
|
||||
}
|
||||
|
||||
/**
|
||||
* Determines whether $(D_PARAM x) is a normilized number or not.
|
||||
|
||||
* Normalized number is a number that can be represented as
|
||||
*
|
||||
* <pre>
|
||||
* m*2<sup>e</sup>
|
||||
* </pre>
|
||||
*
|
||||
* where $(I m) is the mantissa and $(I e) is an exponent that fits into the
|
||||
* exponent field of the type $(D_PARAM F).
|
||||
*
|
||||
* `0` is neither normalized nor denormalized.
|
||||
*
|
||||
* Params:
|
||||
* F = Type of the floating point number.
|
||||
* x = Floating point number.
|
||||
*
|
||||
* Returns: $(D_KEYWORD true) if $(D_PARAM x) is a normilized number,
|
||||
* $(D_KEYWORD false) otherwise.
|
||||
*
|
||||
* See_Also: $(D_PSYMBOL isSubnormal).
|
||||
*/
|
||||
bool isNormal(F)(F x)
|
||||
if (isFloatingPoint!F)
|
||||
{
|
||||
static if (ieeePrecision!F == IEEEPrecision.single
|
||||
|| ieeePrecision!F == IEEEPrecision.double_)
|
||||
{
|
||||
FloatBits!F bits;
|
||||
bits.floating = x;
|
||||
bits.integral &= bits.expMask;
|
||||
return bits.integral != 0 && bits.integral != bits.expMask;
|
||||
}
|
||||
else static if (ieeePrecision!F == IEEEPrecision.doubleExtended)
|
||||
{
|
||||
return classify(x) == FloatingPointClass.normal;
|
||||
}
|
||||
}
|
||||
|
||||
///
|
||||
pure nothrow @safe @nogc unittest
|
||||
{
|
||||
assert(!isNormal(0.0f));
|
||||
assert(!isNormal(float.nan));
|
||||
assert(!isNormal(float.infinity));
|
||||
assert(isNormal(0.3f));
|
||||
assert(!isNormal(5.87747e-38f / 10));
|
||||
|
||||
assert(!isNormal(0.0));
|
||||
assert(!isNormal(double.nan));
|
||||
assert(!isNormal(double.infinity));
|
||||
assert(isNormal(1.4));
|
||||
assert(!isNormal(1.11254e-307 / 10));
|
||||
|
||||
assert(!isNormal(0.0L));
|
||||
assert(!isNormal(real.nan));
|
||||
assert(!isNormal(real.infinity));
|
||||
}
|
||||
|
||||
/**
|
||||
* Determines whether the sign bit of $(D_PARAM x) is set or not.
|
||||
*
|
||||
* If the sign bit, $(D_PARAM x) is a negative number, otherwise positive.
|
||||
*
|
||||
* Params:
|
||||
* F = Type of the floating point number.
|
||||
* x = Floating point number.
|
||||
*
|
||||
* Returns: $(D_KEYWORD true) if the sign bit of $(D_PARAM x) is set,
|
||||
* $(D_KEYWORD false) otherwise.
|
||||
*/
|
||||
bool signBit(F)(F x)
|
||||
if (isFloatingPoint!F)
|
||||
{
|
||||
FloatBits!F bits;
|
||||
bits.floating = x;
|
||||
static if (ieeePrecision!F == IEEEPrecision.single)
|
||||
{
|
||||
return (bits.integral & (1 << 31)) != 0;
|
||||
}
|
||||
else static if (ieeePrecision!F == IEEEPrecision.double_)
|
||||
{
|
||||
return (bits.integral & (1L << 63)) != 0;
|
||||
}
|
||||
else static if (ieeePrecision!F == IEEEPrecision.doubleExtended)
|
||||
{
|
||||
return (bits.exp & (1 << 15)) != 0;
|
||||
}
|
||||
}
|
||||
|
||||
///
|
||||
pure nothrow @safe @nogc unittest
|
||||
{
|
||||
assert(signBit(-1.0f));
|
||||
assert(!signBit(1.0f));
|
||||
|
||||
assert(signBit(-1.0));
|
||||
assert(!signBit(1.0));
|
||||
|
||||
assert(signBit(-1.0L));
|
||||
assert(!signBit(1.0L));
|
||||
}
|
||||
|
||||
/**
|
||||
* Computes $(D_PARAM x) to the power $(D_PARAM y) modulo $(D_PARAM z).
|
||||
*
|
||||
|
|
|
|||
Loading…
Reference in New Issue