Overview of HP-UX Math Libraries

Math Libraries and System Architecture

The libm and libcl math libraries on HP-UX operating system at Release 10.30 and later are targeted primarily to the PA-RISC 1.1 architecture (PA1.1). They also run well on PA-RISC 2.0 (PA2.0) systems.

The libraries will execute on all HP 9000 systems that run HP-UX Release 10.30 and later.

The HP Fortran 90 and HP FORTRAN/9000 products supply two versions of the BLAS library, one specially tuned for PA1.1 systems and the other specially tuned for PA2.0 systems.

	NOTE: The PA-RISC 1.0 architecture is no longer supported, and the PA1.0 libraries are no longer provided on HP-UX systems.

All HP 9000 systems except the oldest Series 800 systems are PA1.1-based or PA2.0-based. If you do not know your system's architecture type, see “Determining Your System's Architecture Type”.

For complete information about the math libraries, see Chapter 4 “HP-UX Math Libraries on HP 9000 Systems”.

Determining Your System's Architecture Type

There are two main ways to find the architecture type of your system. To do it from the command line:

1. Issue the command uname -m to learn the model number of your system. For example:

   $ uname -m 9000/879

2. Look up the second part of the model number in the file /opt/langtools/lib/sched.models to find its architecture type. For example:

   $ grep 879 /opt/langtools/lib/sched.models 879 2.0 PA8000

   The 2.0 indicates that a Model 879 is PA2.0-based.

You can also learn the system architecture type at run time at HP-UX Release 10.x. A simple program that gives you useful information follows.

Example 1-1 Sample Program: get_arch.c

#include <stdio.h> #include <sys/utsname.h> extern int _SYSTEM_ID; extern int _CPU_REVISION; struct utsname uts; int main(void) { uname(&uts); printf("Release = %s\n", uts.release); printf("_SYSTEM_ID = %x\n", _SYSTEM_ID); printf("_CPU_REVISION = %x\n", _CPU_REVISION); }

The uts.release is the release of HP-UX on the system where you run the program. The _SYSTEM_ID is the kind of code the compiler generated. The _CPU_REVISION is the architecture type.

If you compile this program on a PA1.1 system, then run it on a PA2.0 system running HP-UX Release 10.30, you get results like the following:

Release = B.10.30 _SYSTEM_ID = 210 _CPU_REVISION = 214

The release, 10.30, is easy to decipher. To decode the other results, search the file /usr/include/sys/unistd.h:

$ grep 210 /usr/include/sys/unistd.h # define CPU_PA_RISC1_1 0x210 /* HP PA-RISC1.1 */ $ grep 214 /usr/include/sys/unistd.h /# define CPU_PA_RISC2_0 0x214 /* HP PA-RISC2.0 */

The compiler generated PA1.1 code, which is running on a PA2.0 system.

Selecting Different Versions of the Math Libraries

If you use a compilation command (f90, cc, and so on) to invoke the link editor (ld), the selection of math libraries is driven by the +DA compiler option, which allows you to generate PA1.1 code (+DA1.1) or PA2.0 code (+DA2.0). By default, the compiler generates code for the kind of system on which you are running the compiler. This ensures the best possible performance on that system.

If your application must run on both PA1.1 and PA2.0 systems, compile with +DA1.1. Code compiled with +DA2.0 will run only on PA2.0 systems.

When you select +DA1.1 or +DA2.0, the compilation command invokes ld with a library search path that begins with the PA1.1 library directories. Again, the search path may vary from compiler to compiler. For example, if you invoke the HP Fortran 90 compiler with +DA2.0, it contains the following:

/opt/fortran90/lib/pa2.0
/opt/fortran90/lib
/usr/lib
/opt/langtools/lib

Locations of the Math Libraries at Release 10.30

At Release 10.30, the main HP-UX math libraries are in the directory /usr/lib. The BLAS library is in both /opt/fortran90/lib and /opt/fortran/lib. The obsolete vector library exists only in /opt/fortran/old/lib.

	NOTE: The PA1.0 libraries are no longer provided.

Table 1-2 “Math Library Path Names” shows the math library path names.

Figure 1-1 “Math Library Directory Hierarchy at Release 10.30” illustrates the directory hierarchy for the math libraries.

Figure 1-1 Math Library Directory Hierarchy at Release 10.30