How to perform Modulo of boost::cpp_dec_float_50 and boost::int1024_t Data Types?

Asked Sep 11 '19 at 11:54

Active Sep 11 '19 at 11:54

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I'm trying to perform a modulo operation on two numbers. One is a cpp_dec_float_50 type (decimal) number, and the other is a int1024_t type number - both supplied by the Boost Multiprecision C++ library.

I've tried using the % operator, and the Standard Library's fmod() function, but alas they aren't designed for such data types. I've scoured the Boost documentation however there is no trace of a modulous alternative that would work with its own floating point data types.

Please note that the int1024_t value is very large.

There must be SOME way to perform a modulo operation on such values, hopefully someone can shed some light on it for me.

Cheers.

asked Sep 11 '19 at 11:54

Zaxter5

You can't use the modulo operator on floating point numbers. – user14717 Sep 11 '19 at 11:57
@user14717 I'm aware, that's why I tried the fmod() operation. – Zaxter5 Sep 11 '19 at 12:00
Do you know that your floating point value in an integer? If so cast it to `int1024_t`. – user14717 Sep 11 '19 at 12:15
@user14717 how do you mean? My floating point value may be 0.2, for instance. I don't think I can cast that to int1024_t. – Zaxter5 Sep 11 '19 at 12:17
If it's 0.2, then how do you define the modulo operation? – user14717 Sep 11 '19 at 12:19
@user14717 Well it would be fmod(0.2, 205757961451002850) for instance, but the second number is too big for primitive types. – Zaxter5 Sep 11 '19 at 12:22
I'm asking "what do you think 0.2 % 205757961451002850 to means?" – user14717 Sep 11 '19 at 12:34
Obviously what is the remainder after dividing those two numbers. – Zaxter5 Sep 11 '19 at 12:59
Why not define it as a free function yourself? It's just a division, truncate to an integer then a subtraction? – Mansoor Sep 11 '19 at 13:39
"Obviously what is the remainder after dividing those two numbers." There is no remainder. – user14717 Sep 11 '19 at 14:21

How to perform Modulo of boost::cpp_dec_float_50 and boost::int1024_t Data Types?

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