I8LIB
A Double Precision Integer Arithmetic Utility Library

I8LIB is a FORTRAN90 library which contains a number of utility routines for "I8" or "double precision integer" arithmetic.

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Languages:

I8LIB is available in a C version and a C++ version and a FORTRAN90 version.

Related Data and Programs:

C4LIB, a FORTRAN90 library which implements certain elementary functions for "C4" or single precision complex variables;

C8LIB, a FORTRAN90 library which implements certain elementary functions for "C8" or double precision complex variables;

I4LIB, a FORTRAN90 library which contains many utility routines, using "I4" or "single precision integer" arithmetic.

L4LIB, a FORTRAN90 library which contains many utility routines, using one byte logical (L4) variables.

R4LIB, a FORTRAN90 library which contains many utility routines, using "R4" or "single precision real" arithmetic.

R8LIB, a FORTRAN90 library which contains many utility routines, using "R8" or "double precision real" arithmetic.

SUBPAK, a FORTRAN90 library which contains many utility routines;

Source Code:

• i8lib.f90, the source code;

Examples and Tests:

• i8lib_test.f90, a sample calling program;
• i8lib_test.txt, the output file.

List of Routines:

• I8_BIT_HI1 returns the position of the high 1 bit base 2 in an I8.
• I8_BIT_LO0 returns the position of the low 0 bit base 2 in an I8.
• I8_CHOOSE computes the binomial coefficient C(N,K) as an I8.
• I8_HUGE returns a "huge" I8.
• I8_HUGE_NORMALIZER returns the "normalizer" for I8_HUGE.
• I8_UNIFORM returns a scaled pseudorandom I8.
• I8_XOR calculates the exclusive OR of two I8's.
• R8I8_UNIFORM returns a scaled pseudorandom R8 using an I8 seed.
• R8I8_UNIFORM_01 returns a unit pseudorandom R8 using an I8 seed.
• TIMESTAMP prints the current YMDHMS date as a time stamp.

You can go up one level to the FORTRAN90 source codes.