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I need to manage more than 15 digits of precision in my Visual C++ program and libraries

Hi,

I have a program and libraries written in Visual C++ 2005 where i use variables of type double. So far i have been working with this data type with the maximum 15 digits of precision but now i have a request from my customer for supporting 16, 17 and more digits of precision. I don't know how to do this or even if that is possible.

What can i do?
Should i use the boost libraries?
Write my own type and change the data types all over the code (thousands of lines involved) ?

Thanks and regards,

Johann

ASKER CERTIFIED SOLUTION

jkr

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sarabande

it would be not so difficult to use own type highdouble instead of double in your code. you can do such a substitution in very short time with case sensitive and full-word replacement. then make a central typedef double highdouble; and your programs should build. you then can decide how to implement highdouble, either made by your own for example based on 64-bit integer or using an appropriate type of a foreign library as base.

Sara

JohannRamon

ASKER

Hi,

Thanks for the prompt answers!

jkr: I have checked the libraries and so far NTL types (xdouble or RR) look like my best solution. It looks like the library i already have "boost" doesn't have an appropriate data type.

Sara: It looks like the best path for this large amount of code is the search-replace of the data type. If i include the foreign library it would still be necessary to make the "typedef double highdouble"?

Thanks again and regards,

Johann

sarabande

you probably then would replace the typedef by

typedef long_double_from_library highdouble;

or in case the new (class) type would not provide an interface so that it could substitute a double, you would implement the type highdouble yourself taking the type from the library as a base.

Sara

JohannRamon

ASKER

Hi,

Funny as it sounds, my management wants a "commercial" solution because they feel it is necessary to have a "provider" which can give us support and warranties backed up with a contract (the perceived risk of precision errors is too high for us to assume it alone).

I´m sorry for this added condition. Any suggested option?

Thanks again and regards,

Johann

Dirk Haest

This question has been classified as abandoned and is being closed as part of the Cleanup Program. See my comment at the end of the question for more details.