"""
Low-level LAPACK functions (:mod:`scipy.linalg.lapack`)
=======================================================
This module contains low-level functions from the LAPACK library.
The `*gegv` family of routines have been removed from LAPACK 3.6.0
and have been deprecated in SciPy 0.17.0. They will be removed in
a future release.
.. versionadded:: 0.12.0
.. warning::
These functions do little to no error checking.
It is possible to cause crashes by mis-using them,
so prefer using the higher-level routines in `scipy.linalg`.
Finding functions
-----------------
.. autosummary::
get_lapack_funcs
All functions
-------------
.. autosummary::
:toctree: generated/
sgbsv
dgbsv
cgbsv
zgbsv
sgbtrf
dgbtrf
cgbtrf
zgbtrf
sgbtrs
dgbtrs
cgbtrs
zgbtrs
sgebal
dgebal
cgebal
zgebal
sgees
dgees
cgees
zgees
sgeev
dgeev
cgeev
zgeev
sgeev_lwork
dgeev_lwork
cgeev_lwork
zgeev_lwork
sgegv
dgegv
cgegv
zgegv
sgehrd
dgehrd
cgehrd
zgehrd
sgehrd_lwork
dgehrd_lwork
cgehrd_lwork
zgehrd_lwork
sgelss
dgelss
cgelss
zgelss
sgelss_lwork
dgelss_lwork
cgelss_lwork
zgelss_lwork
sgelsd
dgelsd
cgelsd
zgelsd
sgelsd_lwork
dgelsd_lwork
cgelsd_lwork
zgelsd_lwork
sgelsy
dgelsy
cgelsy
zgelsy
sgelsy_lwork
dgelsy_lwork
cgelsy_lwork
zgelsy_lwork
sgeqp3
dgeqp3
cgeqp3
zgeqp3
sgeqrf
dgeqrf
cgeqrf
zgeqrf
sgerqf
dgerqf
cgerqf
zgerqf
sgesdd
dgesdd
cgesdd
zgesdd
sgesdd_lwork
dgesdd_lwork
cgesdd_lwork
zgesdd_lwork
sgesv
dgesv
cgesv
zgesv
sgetrf
dgetrf
cgetrf
zgetrf
sgetri
dgetri
cgetri
zgetri
sgetri_lwork
dgetri_lwork
cgetri_lwork
zgetri_lwork
sgetrs
dgetrs
cgetrs
zgetrs
sgges
dgges
cgges
zgges
sggev
dggev
cggev
zggev
chbevd
zhbevd
chbevx
zhbevx
cheev
zheev
cheevd
zheevd
cheevr
zheevr
chegv
zhegv
chegvd
zhegvd
chegvx
zhegvx
slarf
dlarf
clarf
zlarf
slarfg
dlarfg
clarfg
zlarfg
slartg
dlartg
clartg
zlartg
slasd4
dlasd4
slaswp
dlaswp
claswp
zlaswp
slauum
dlauum
clauum
zlauum
spbsv
dpbsv
cpbsv
zpbsv
spbtrf
dpbtrf
cpbtrf
zpbtrf
spbtrs
dpbtrs
cpbtrs
zpbtrs
sposv
dposv
cposv
zposv
spotrf
dpotrf
cpotrf
zpotrf
spotri
dpotri
cpotri
zpotri
spotrs
dpotrs
cpotrs
zpotrs
crot
zrot
strsyl
dtrsyl
ctrsyl
ztrsyl
strtri
dtrtri
ctrtri
ztrtri
strtrs
dtrtrs
ctrtrs
ztrtrs
cunghr
zunghr
cungqr
zungqr
cungrq
zungrq
cunmqr
zunmqr
sgtsv
dgtsv
cgtsv
zgtsv
sptsv
dptsv
cptsv
zptsv
slamch
dlamch
sorghr
dorghr
sorgqr
dorgqr
sorgrq
dorgrq
sormqr
dormqr
ssbev
dsbev
ssbevd
dsbevd
ssbevx
dsbevx
ssyev
dsyev
ssyevd
dsyevd
ssyevr
dsyevr
ssygv
dsygv
ssygvd
dsygvd
ssygvx
dsygvx
slange
dlange
clange
zlange
"""
#
# Author: Pearu Peterson, March 2002
#
from __future__ import division, print_function, absolute_import
__all__ = ['get_lapack_funcs']
import numpy as _np
from .blas import _get_funcs
# Backward compatibility:
from .blas import find_best_blas_type as find_best_lapack_type
from scipy.linalg import _flapack
try:
from scipy.linalg import _clapack
except ImportError:
_clapack = None
# Backward compatibility
from scipy._lib._util import DeprecatedImport as _DeprecatedImport
clapack = _DeprecatedImport("scipy.linalg.blas.clapack", "scipy.linalg.lapack")
flapack = _DeprecatedImport("scipy.linalg.blas.flapack", "scipy.linalg.lapack")
# Expose all functions (only flapack --- clapack is an implementation detail)
empty_module = None
from scipy.linalg._flapack import *
del empty_module
_dep_message = """The `*gegv` family of routines has been deprecated in
LAPACK 3.6.0 in favor of the `*ggev` family of routines.
The corresponding wrappers will be removed from SciPy in
a future release."""
cgegv = _np.deprecate(cgegv, old_name='cgegv', message=_dep_message)
dgegv = _np.deprecate(dgegv, old_name='dgegv', message=_dep_message)
sgegv = _np.deprecate(sgegv, old_name='sgegv', message=_dep_message)
zgegv = _np.deprecate(zgegv, old_name='zgegv', message=_dep_message)
# Modyfy _flapack in this scope so the deprecation warnings apply to
# functions returned by get_lapack_funcs.
_flapack.cgegv = cgegv
_flapack.dgegv = dgegv
_flapack.sgegv = sgegv
_flapack.zgegv = zgegv
# some convenience alias for complex functions
_lapack_alias = {
'corghr': 'cunghr', 'zorghr': 'zunghr',
'corghr_lwork': 'cunghr_lwork', 'zorghr_lwork': 'zunghr_lwork',
'corgqr': 'cungqr', 'zorgqr': 'zungqr',
'cormqr': 'cunmqr', 'zormqr': 'zunmqr',
'corgrq': 'cungrq', 'zorgrq': 'zungrq',
}
[docs]def get_lapack_funcs(names, arrays=(), dtype=None):
"""Return available LAPACK function objects from names.
Arrays are used to determine the optimal prefix of LAPACK routines.
Parameters
----------
names : str or sequence of str
Name(s) of LAPACK functions without type prefix.
arrays : sequence of ndarrays, optional
Arrays can be given to determine optimal prefix of LAPACK
routines. If not given, double-precision routines will be
used, otherwise the most generic type in arrays will be used.
dtype : str or dtype, optional
Data-type specifier. Not used if `arrays` is non-empty.
Returns
-------
funcs : list
List containing the found function(s).
Notes
-----
This routine automatically chooses between Fortran/C
interfaces. Fortran code is used whenever possible for arrays with
column major order. In all other cases, C code is preferred.
In LAPACK, the naming convention is that all functions start with a
type prefix, which depends on the type of the principal
matrix. These can be one of {'s', 'd', 'c', 'z'} for the numpy
types {float32, float64, complex64, complex128} respectevely, and
are stored in attribute `typecode` of the returned functions.
"""
return _get_funcs(names, arrays, dtype,
"LAPACK", _flapack, _clapack,
"flapack", "clapack", _lapack_alias)
def _compute_lwork(routine, *args, **kwargs):
"""
Round floating-point lwork returned by lapack to integer.
Several LAPACK routines compute optimal values for LWORK, which
they return in a floating-point variable. However, for large
values of LWORK, single-precision floating point is not sufficient
to hold the exact value --- some LAPACK versions (<= 3.5.0 at
least) truncate the returned integer to single precision and in
some cases this can be smaller than the required value.
"""
wi = routine(*args, **kwargs)
if len(wi) < 2:
raise ValueError('')
info = wi[-1]
if info != 0:
raise ValueError("Internal work array size computation failed: "
"%d" % (info,))
lwork = [w.real for w in wi[:-1]]
dtype = getattr(routine, 'dtype', None)
if dtype == _np.float32 or dtype == _np.complex64:
# Single-precision routine -- take next fp value to work
# around possible truncation in LAPACK code
lwork = _np.nextafter(lwork, _np.inf, dtype=_np.float32)
lwork = _np.array(lwork, _np.int64)
if _np.any(_np.logical_or(lwork < 0, lwork > _np.iinfo(_np.int32).max)):
raise ValueError("Too large work array required -- computation cannot "
"be performed with standard 32-bit LAPACK.")
lwork = lwork.astype(_np.int32)
if lwork.size == 1:
return lwork[0]
return lwork