1dnl @synopsis ACX_LAPACK([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
2dnl
3dnl This macro looks for a library that implements the LAPACK
4dnl linear-algebra interface (see http://www.netlib.org/lapack/).
5dnl On success, it sets the LAPACK_LIBS output variable to
6dnl hold the requisite library linkages.
7dnl
8dnl To link with LAPACK, you should link with:
9dnl 	$LAPACK_LIBS $BLAS_LIBS $LIBS $FLIBS
10dnl in that order.  BLAS_LIBS is the output variable of the ACX_BLAS
11dnl macro, called automatically.  FLIBS is the output variable of the
12dnl AC_F77_LIBRARY_LDFLAGS macro (called if necessary by ACX_BLAS),
13dnl and is sometimes necessary in order to link with F77 libraries.
14dnl Users will also need to use AC_F77_DUMMY_MAIN (see the autoconf
15dnl manual), for the same reason.
16dnl
17dnl The user may also use --with-lapack=<lib> in order to use some
18dnl specific LAPACK library <lib>.  In order to link successfully,
19dnl however, be aware that you will probably need to use the same
20dnl Fortran compiler (which can be set via the F77 env. var.) as
21dnl was used to compile the LAPACK and BLAS libraries.
22dnl
23dnl ACTION-IF-FOUND is a list of shell commands to run if a LAPACK
24dnl library is found, and ACTION-IF-NOT-FOUND is a list of commands
25dnl to run it if it is not found.  If ACTION-IF-FOUND is not specified,
26dnl the default action will define HAVE_LAPACK.
27dnl
28dnl @version $Id: acx_lapack.m4,v 1.3 2006/07/05 01:21:07 stevenj Exp $
29dnl @author Steven G. Johnson <stevenj@alum.mit.edu>
30
31AC_DEFUN([ACX_LAPACK], [
32AC_REQUIRE([ACX_BLAS])
33acx_lapack_ok=no
34
35AC_ARG_WITH(lapack,
36	[AC_HELP_STRING([--with-lapack=<lib>], [use LAPACK library <lib>])])
37case $with_lapack in
38	yes | "") ;;
39	no) acx_lapack_ok=disable ;;
40	-* | */* | *.a | *.so | *.so.* | *.o) LAPACK_LIBS="$with_lapack" ;;
41	*) LAPACK_LIBS="-l$with_lapack" ;;
42esac
43
44# Get fortran linker name of LAPACK function to check for.
45AC_F77_FUNC(cheev)
46
47# We cannot use LAPACK if BLAS is not found
48if test "x$acx_blas_ok" != xyes; then
49	acx_lapack_ok=noblas
50fi
51
52# First, check LAPACK_LIBS environment variable
53if test "x$LAPACK_LIBS" != x; then
54	save_LIBS="$LIBS"; LIBS="$LAPACK_LIBS $BLAS_LIBS $LIBS $FLIBS"
55	AC_MSG_CHECKING([for $cheev in $LAPACK_LIBS])
56	AC_TRY_LINK_FUNC($cheev, [acx_lapack_ok=yes], [LAPACK_LIBS=""])
57	AC_MSG_RESULT($acx_lapack_ok)
58	LIBS="$save_LIBS"
59	if test acx_lapack_ok = no; then
60		LAPACK_LIBS=""
61	fi
62fi
63
64# LAPACK linked to by default?  (is sometimes included in BLAS lib)
65if test $acx_lapack_ok = no; then
66	save_LIBS="$LIBS"; LIBS="$LIBS $BLAS_LIBS $FLIBS"
67	AC_CHECK_FUNC($cheev, [acx_lapack_ok=yes])
68	LIBS="$save_LIBS"
69fi
70
71# Generic LAPACK library?
72for lapack in lapack lapack_rs6k; do
73	if test $acx_lapack_ok = no; then
74		save_LIBS="$LIBS"; LIBS="$BLAS_LIBS $LIBS"
75		AC_CHECK_LIB($lapack, $cheev,
76		    [acx_lapack_ok=yes; LAPACK_LIBS="-l$lapack"], [], [$FLIBS])
77		LIBS="$save_LIBS"
78	fi
79done
80
81AC_SUBST(LAPACK_LIBS)
82
83# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
84if test x"$acx_lapack_ok" = xyes; then
85        ifelse([$1],,AC_DEFINE(HAVE_LAPACK,1,[Define if you have LAPACK library.]),[$1])
86        :
87else
88        acx_lapack_ok=no
89        $2
90fi
91])dnl ACX_LAPACK
92