`scipy.linalg._flapack:chfrk`

Signature

def chfrk(n, k, alpha, a, beta, c, transr = N, uplo = U, trans = N, overwrite_c = 0)

Hermitian rank-k update of a matrix held in rectangular full packed (RFP) storage (LAPACK chfrk).

Computes c := alpha * a @ a.conj().T + beta * c when trans is 'N', or c := alpha * a.conj().T @ a + beta * c when it is 'C'.

n : int: Order of the square matrix.
k : int: Inner dimension of the update.
alpha : float: Scalar the rank-k term is multiplied by. Real for every flavor.
a : ndarray: Shape (max(n, 1), k) when trans is 'N', (max(k, 1), n) otherwise. The leading dimension follows n and k rather than a, so the row count must match exactly.
beta : float: Scalar c is scaled by before the update. Real for every flavor.
c : ndarray: The matrix to update, in RFP storage, length n * (n + 1) / 2.
transr : str, optional: 'N' for the normal RFP layout, 'C' for the transposed one. Default is 'N'.
uplo : str, optional: 'U' if c holds the upper triangle, 'L' if lower. Default is 'U'.
trans : str, optional: 'N' for a @ a.conj().T, 'C' for the conjugate transpose product. Default is 'N'.
overwrite_c : int, optional: If nonzero, c may be overwritten in place. Default is 0.