## digitalmars.D.learn - Split Real / Float into Mantissa, Exponent, and Base

- Jonathan M. Wilbur (11/11) Mar 03 2017 I have tried to come up with a good way to get the mantissa,
- pineapple (5/17) Mar 03 2017 The various functions in std.math mostly extract these values on
- Marc =?UTF-8?B?U2Now7x0eg==?= (4/16) Mar 06 2017 See std.bitmanip.FloatRep and std.bitmanip.DoubleRep:

I have tried to come up with a good way to get the mantissa, exponent, and base from a real number, and I just can't come up with a good cross-platform way of doing it. I know about std.math.frexp(), but that function only gives you another real as the mantissa. I need an integral mantissa, exponent, and base. Is there either (1) a crafty, cross-platform way of doing this or (2) a function in a standard library that does this that I somehow missed? If there is no such function, what are your thoughts on me implementing such a thing and submitting it to Phobos, probably similar to how frexp is implemented (elseifs for each FP format)?

Mar 03 2017

On Friday, 3 March 2017 at 18:09:02 UTC, Jonathan M. Wilbur wrote:I have tried to come up with a good way to get the mantissa, exponent, and base from a real number, and I just can't come up with a good cross-platform way of doing it. I know about std.math.frexp(), but that function only gives you another real as the mantissa. I need an integral mantissa, exponent, and base. Is there either (1) a crafty, cross-platform way of doing this or (2) a function in a standard library that does this that I somehow missed? If there is no such function, what are your thoughts on me implementing such a thing and submitting it to Phobos, probably similar to how frexp is implemented (elseifs for each FP format)?The various functions in std.math mostly extract these values on their own, using the floatTraits template to help. The mach library has the module mach.math.floats.extract: https://github.com/pineapplemachine/mach.d/tree/master/mach/math/floats

Mar 03 2017

On Friday, 3 March 2017 at 18:09:02 UTC, Jonathan M. Wilbur wrote:I have tried to come up with a good way to get the mantissa, exponent, and base from a real number, and I just can't come up with a good cross-platform way of doing it. I know about std.math.frexp(), but that function only gives you another real as the mantissa. I need an integral mantissa, exponent, and base. Is there either (1) a crafty, cross-platform way of doing this or (2) a function in a standard library that does this that I somehow missed? If there is no such function, what are your thoughts on me implementing such a thing and submitting it to Phobos, probably similar to how frexp is implemented (elseifs for each FP format)?See std.bitmanip.FloatRep and std.bitmanip.DoubleRep: https://dlang.org/phobos/std_bitmanip.html#.FloatRep https://dlang.org/phobos/std_bitmanip.html#.DoubleRep

Mar 06 2017