B &]\N( @sdZddlmZmZmZddlZddlmZmZmZm Z ddl m Z ddl m Z ddlmZmZdd lmZdd lmZd d gZd ddgZddd ZeejZeejZdddddddddd ZdddddddZddgddggZddZddZ ddd Z!dS) zSchur decomposition functions.)divisionprint_functionabsolute_importN)asarray_chkfinitesingleasarrayarray)norm)callable) LinAlgError _datacopied)get_lapack_funcs)eigvalsschurrsf2csfildrealFTc Cs|dkrtd|rt|}nt|}t|jdksH|jd|jdkrPtd|jj}|dkr|dkr|tkr|d }d }n|d }d }|pt ||}t d |f\}|d ks|d kr|dd|d d} | ddj t j }|d krd} dd} nld} t|r |} nX|dkr dd} nD|dkr4dd} n0|dkrHdd} n|dkr\dd} ntd|| |||| d} | d } | dkrtd| nN| |jddkrtdn0| |jddkrtdn| dkrtd | dkr| d| d!fS| d| d!| dfSd S)"a Compute Schur decomposition of a matrix. The Schur decomposition is:: A = Z T Z^H where Z is unitary and T is either upper-triangular, or for real Schur decomposition (output='real'), quasi-upper triangular. In the quasi-triangular form, 2x2 blocks describing complex-valued eigenvalue pairs may extrude from the diagonal. Parameters ---------- a : (M, M) array_like Matrix to decompose output : {'real', 'complex'}, optional Construct the real or complex Schur decomposition (for real matrices). lwork : int, optional Work array size. If None or -1, it is automatically computed. overwrite_a : bool, optional Whether to overwrite data in a (may improve performance). sort : {None, callable, 'lhp', 'rhp', 'iuc', 'ouc'}, optional Specifies whether the upper eigenvalues should be sorted. A callable may be passed that, given a eigenvalue, returns a boolean denoting whether the eigenvalue should be sorted to the top-left (True). Alternatively, string parameters may be used:: 'lhp' Left-hand plane (x.real < 0.0) 'rhp' Right-hand plane (x.real > 0.0) 'iuc' Inside the unit circle (x*x.conjugate() <= 1.0) 'ouc' Outside the unit circle (x*x.conjugate() > 1.0) Defaults to None (no sorting). check_finite : bool, optional Whether to check that the input matrix contains only finite numbers. Disabling may give a performance gain, but may result in problems (crashes, non-termination) if the inputs do contain infinities or NaNs. Returns ------- T : (M, M) ndarray Schur form of A. It is real-valued for the real Schur decomposition. Z : (M, M) ndarray An unitary Schur transformation matrix for A. It is real-valued for the real Schur decomposition. sdim : int If and only if sorting was requested, a third return value will contain the number of eigenvalues satisfying the sort condition. Raises ------ LinAlgError Error raised under three conditions: 1. The algorithm failed due to a failure of the QR algorithm to compute all eigenvalues 2. If eigenvalue sorting was requested, the eigenvalues could not be reordered due to a failure to separate eigenvalues, usually because of poor conditioning 3. If eigenvalue sorting was requested, roundoff errors caused the leading eigenvalues to no longer satisfy the sorting condition See also -------- rsf2csf : Convert real Schur form to complex Schur form Examples -------- >>> from scipy.linalg import schur, eigvals >>> A = np.array([[0, 2, 2], [0, 1, 2], [1, 0, 1]]) >>> T, Z = schur(A) >>> T array([[ 2.65896708, 1.42440458, -1.92933439], [ 0. , -0.32948354, -0.49063704], [ 0. , 1.31178921, -0.32948354]]) >>> Z array([[0.72711591, -0.60156188, 0.33079564], [0.52839428, 0.79801892, 0.28976765], [0.43829436, 0.03590414, -0.89811411]]) >>> T2, Z2 = schur(A, output='complex') >>> T2 array([[ 2.65896708, -1.22839825+1.32378589j, 0.42590089+1.51937378j], [ 0. , -0.32948354+0.80225456j, -0.59877807+0.56192146j], [ 0. , 0. , -0.32948354-0.80225456j]]) >>> eigvals(T2) array([2.65896708, -0.32948354+0.80225456j, -0.32948354-0.80225456j]) An arbitrary custom eig-sorting condition, having positive imaginary part, which is satisfied by only one eigenvalue >>> T3, Z3, sdim = schur(A, output='complex', sort=lambda x: x.imag > 0) >>> sdim 1 )rcomplexrcz%argument must be 'real', or 'complex'rr zexpected square matrix)rr)FDrr)geesNcSsdS)N)xrr8lib/python3.7/site-packages/scipy/linalg/decomp_schur.pyszschur..)lworkcSsdS)Nr)rrrr r!sZlhpcSs |jdkS)Ng)r)rrrr r!sZrhpcSs |jdkS)Ng)r)rrrr r!sZiuccSs t|dkS)Ng?)abs)rrrr r!sZouccSs t|dkS)Ng?)r$)rrrr r!szZ'sort' parameter must either be 'None', or a callable, or one of ('lhp','rhp','iuc','ouc'))r" overwrite_asort_tz0illegal value in {}-th argument of internal geesz2Eigenvalues could not be separated for reordering.z2Leading eigenvalues do not satisfy sort condition.z0Schur form not found. Possibly ill-conditioned.) ValueErrorrrlenshapedtypechar_double_precisionastyper rrnumpyintr formatr ) aoutputr"r%sort check_finiteZa1typrresultr&Z sfunctioninforrr rsbc "                   ) bhBrrfrrr)rrr<rrrr<rrcGsFd}d}x0|D](}|jj}t|t|}t|t|}qWt||S)Nr)r+r,max _array_kind_array_precision _array_type)arraysZkindZ precisionr2trrr _commonTypes rCcGsZd}x8|D]0}|jj|kr*||f}q |||f}q Wt|dkrR|dS|SdS)Nrr r)r+r,copyr.r))typerAZ cast_arraysr2rrr _castCopys   rFc Cs|rtt||f\}}ntt||f\}}xHt||gD]8\}}|jdks^|jd|jdkr8tdd|q8W|jd|jdkrtd|j|j|jd}t||t dgd}t |||\}}xt |ddd D]}t |||dft t ||d|dft |||fkr~t||d|d|d|df|||f}t|d|||dfg} |d| } |||df| } t | | g| | gg|d } | ||d|d|dd f||d|d|dd f<|d |d|d|df| j|d |d|d|df<|d d |d|df| j|d d |d|df<d |||df<qW||fS) a6 Convert real Schur form to complex Schur form. Convert a quasi-diagonal real-valued Schur form to the upper triangular complex-valued Schur form. Parameters ---------- T : (M, M) array_like Real Schur form of the original array Z : (M, M) array_like Schur transformation matrix check_finite : bool, optional Whether to check that the input arrays contain only finite numbers. Disabling may give a performance gain, but may result in problems (crashes, non-termination) if the inputs do contain infinities or NaNs. Returns ------- T : (M, M) ndarray Complex Schur form of the original array Z : (M, M) ndarray Schur transformation matrix corresponding to the complex form See Also -------- schur : Schur decomposition of an array Examples -------- >>> from scipy.linalg import schur, rsf2csf >>> A = np.array([[0, 2, 2], [0, 1, 2], [1, 0, 1]]) >>> T, Z = schur(A) >>> T array([[ 2.65896708, 1.42440458, -1.92933439], [ 0. , -0.32948354, -0.49063704], [ 0. , 1.31178921, -0.32948354]]) >>> Z array([[0.72711591, -0.60156188, 0.33079564], [0.52839428, 0.79801892, 0.28976765], [0.43829436, 0.03590414, -0.89811411]]) >>> T2 , Z2 = rsf2csf(T, Z) >>> T2 array([[2.65896708+0.j, -1.64592781+0.743164187j, -1.21516887+1.00660462j], [0.+0.j , -0.32948354+8.02254558e-01j, -0.82115218-2.77555756e-17j], [0.+0.j , 0.+0.j, -0.32948354-0.802254558j]]) >>> Z2 array([[0.72711591+0.j, 0.28220393-0.31385693j, 0.51319638-0.17258824j], [0.52839428+0.j, 0.24720268+0.41635578j, -0.68079517-0.15118243j], [0.43829436+0.j, -0.76618703+0.01873251j, -0.03063006+0.46857912j]]) rrr zInput '{}' must be square.ZZTz.Input array shapes must match: Z: {} vs. T: {}g@rr)r+Ng)maprr enumeratendimr*r(r1rCrrFranger$epsrr ZconjdotT) rMZr5ZindXNrBmZmurrsGrrr rs05 B4 BH@)rNFNT)T)"__doc__Z __future__rrrr/rrrrZ numpy.linalgr Zscipy._lib.sixr Zmiscr r ZlapackrZdecompr__all__r-rZfinfofloatrKZfepsr>r?r@rCrFrrrrr s,      !