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solve(a, b, sym_pos=False, lower=False, overwrite_a=False, overwrite_b=False, debug=None, check_finite=True, assume_a='gen', transposed=False)

If the data matrix is known to be a particular type then supplying the corresponding string to assume_a key chooses the dedicated solver. The available options are

Notes

If the input b matrix is a 1-D array with N elements, when supplied together with an NxN input a, it is assumed as a valid column vector despite the apparent size mismatch. This is compatible with the numpy.dot() behavior and the returned result is still 1-D array.

The generic, symmetric, Hermitian and positive definite solutions are obtained via calling ?GESV, ?SYSV, ?HESV, and ?POSV routines of LAPACK respectively.

Parameters

a : (N, N) array_like

Square input data

b : (N, NRHS) array_like

Input data for the right hand side.

sym_pos : bool, optional

Assume a is symmetric and positive definite. This key is deprecated and assume_a = 'pos' keyword is recommended instead. The functionality is the same. It will be removed in the future.

lower : bool, optional

If True, only the data contained in the lower triangle of a. Default is to use upper triangle. (ignored for 'gen' )

overwrite_a : bool, optional

Allow overwriting data in a (may enhance performance). Default is False.

overwrite_b : bool, optional

Allow overwriting data in b (may enhance performance). Default is False.

check_finite : bool, optional

Whether to check that the input matrices 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.

assume_a : str, optional

Valid entries are explained above.

transposed: bool, optional :

If True, a^T x = b for real matrices, raises :None:None:`NotImplementedError` for complex matrices (only for True).

Raises

ValueError

If size mismatches detected or input a is not square.

LinAlgError

If the matrix is singular.

LinAlgWarning

If an ill-conditioned input a is detected.

NotImplementedError

If transposed is True and input a is a complex matrix.

Returns

x : (N, NRHS) ndarray

The solution array.

Solves the linear equation set a * x = b for the unknown x for square a matrix.

Examples

Given a and b, solve for x:

>>> a = np.array([[3, 2, 0], [1, -1, 0], [0, 5, 1]])
... b = np.array([2, 4, -1])
... from scipy import linalg
... x = linalg.solve(a, b)
... x array([ 2., -2., 9.])
>>> np.dot(a, x) == b
array([ True,  True,  True], dtype=bool)
See :

Back References

The following pages refer to to this document either explicitly or contain code examples using this.

scipy.linalg._basic.solve scipy.linalg._solvers.solve_discrete_are scipy.linalg._basic.solve_circulant

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GitHub : /scipy/linalg/_basic.py#40
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