spqr_qmult

sksparse.spqr.spqr_qmult(house, X, method='QX')[source]

Multiply by Q using the Householder representation.

Parameters:

  • house (SPQRHouseholder or tuple) – A tuple (H, tau, v) representing the Householder vectors H, coefficients tau, and the column permutation vector v. Typically, these are created from Ht, R, p = spqr(A, mode='householder').

  • X ((M, N) numpy.ndarray or sparse array) – The matrix to be multiplied. Must have compatible shape with Q.

  • method (str , optional) – The multiplication method. Options are:

    • QX : compute \(Q X\)

    • QTX : compute \(Q^{\top} X\)

    • XQ : compute \(X Q\)

    • XQT : compute \(X Q^{\top}\)

    Default is QX. The transpose is the conjugate transpose for complex data.

Returns:

Y ((M, N) numpy.ndarray or sparse array) – The result of the multiplication. If X is a sparse array, then Y is also returned as a sparse array.

See also

SPQRFactor, spqr_factor, spqr, spqr_solve

Notes

This function is part of an interface to the SuiteSparse SPQR library [1].

Added in version 0.5.0.

References