Review outdated checks in config.h

[jfowkes]

The current autotools based build system generates a config.h with defines based on the dependencies and headers available on a user's system. The thing is, a lot of these are almost always present and it seems pointless to have defines that work around them.

Here is an example generated config.h:

/* config.h.  Generated from config.h.in by configure.  */
/* config.h.in.  Generated from configure.ac by autoheader.  */

/* Define to 1 to enable analyse debugging */
/* #undef ANALDBG */

/* Define to dummy `main' function (if any) required to link to the Fortran
   libraries. */
/* #undef F77_DUMMY_MAIN */

/* Define if F77 and FC dummy `main' functions are identical. */
/* #undef FC_DUMMY_MAIN_EQ_F77 */

/* Define if you have a BLAS library. */
#define HAVE_BLAS 1

/* Define if you have a GTG library. */
/* #undef HAVE_GTG */

/* Define if you have hwloc library */
#define HAVE_HWLOC 1

/* Define to 1 if you have the <inttypes.h> header file. */
#define HAVE_INTTYPES_H 1

/* Define if you have LAPACK library. */
#define HAVE_LAPACK 1

/* Define if you have a MeTiS library. */
#define HAVE_METIS 1

/* Define to 1 if you have the <metis.h> header file. */
/* #undef HAVE_METIS_H */

/* Define to 1 if you are compiling against NVCC */
/* #undef HAVE_NVCC */

/* Define to 1 if you have sched_getcpu(). */
#define HAVE_SCHED_GETCPU 1

/* Define to 1 if you have the <stdint.h> header file. */
#define HAVE_STDINT_H 1

/* Define to 1 if you have the <stdio.h> header file. */
#define HAVE_STDIO_H 1

/* Define to 1 if you have the <stdlib.h> header file. */
#define HAVE_STDLIB_H 1

/* Define to 1 if you have the <strings.h> header file. */
#define HAVE_STRINGS_H 1

/* Define to 1 if you have the <string.h> header file. */
#define HAVE_STRING_H 1

/* Define to 1 if you have the <sys/stat.h> header file. */
#define HAVE_SYS_STAT_H 1

/* Define to 1 if you have the <sys/types.h> header file. */
#define HAVE_SYS_TYPES_H 1

/* Define to 1 if you have the <unistd.h> header file. */
#define HAVE_UNISTD_H 1

/* Name of package */
#define PACKAGE "spral"

/* Define to the address where bug reports for this package should be sent. */
#define PACKAGE_BUGREPORT "hsl@stfc.ac.uk"

/* Define to the full name of this package. */
#define PACKAGE_NAME "spral"

/* Define to the full name and version of this package. */
#define PACKAGE_STRING "spral 2023.09.07"

/* Define to the one symbol short name of this package. */
#define PACKAGE_TARNAME "spral"

/* Define to the home page for this package. */
#define PACKAGE_URL ""

/* Define to the version of this package. */
#define PACKAGE_VERSION "2023.09.07"

/* Define to 1 to enable profiling */
/* #undef PROFILE */

/* The size of `idx_t', as computed by sizeof. */
/* #undef SIZEOF_IDX_T */

/* Define to 1 if you have metis.h. */
#define SPRAL_HAVE_METIS_H 0

/* Define to 1 if all of the C90 standard headers exist (not just the ones
   required in a freestanding environment). This macro is provided for
   backward compatibility; new code need not use it. */
#define STDC_HEADERS 1

/* Version number of package */
#define VERSION "2023.09.07"

Ideally we should be able to remove a lot of these from the codebase with no adverse effects.

[jfowkes]

Looking into these defines in more detail we have the following.

These defines are currently used by the SPRAL codebase and are required:

HAVE_HWLOC -- used to detect NUMA regions
SPRAL_HAVE_METIS_H -- used to define METIS5 32bit/64bit index types
SIZEOF_IDX_T -- used to define METIS5 32bit/64bit index types
HAVE_NVCC -- used to build CUDA kernels
HAVE_SCHED_GETCPU -- used to check if sched_getcpu() can be used

These defines are currently used in the SPRAL codebase for profiling/analysis:

ANALDBG -- enables debugging of SSIDS analyse phase
HAVE_GTG -- the GTG library used for profiling
PROFILE -- enables profiling using the GTG library

The remaining defines are automatically generated by autotools but not used by SPRAL.

@amontoison for meson we only really need the first five to be defined.

[jfowkes]

Also after testing the SPRAL_HAVE_METIS_H set by spral_metis.m4 macro only detects metis.h if --with-metis-inc-dir=/path/to/metis.h is passed to configure. In particular this means that 64bit integer support for METIS5 does not currently work unless this option is specified (SPRAL defaults to 32bit). See #136 for details.