How to show Schulz's method converges $Q$-quadratically?Need some facts about Newton-Schulz iterative method...

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How to show Schulz's method converges $Q$-quadratically?


Need some facts about Newton-Schulz iterative method and its application to sparse matricesJacobi method and HPD MatricesChoosing initial approximation for computing Moore-Penrose inverseProving an identityUnder what conditions does simple iterative method convergeRecurrent sequence of matricesIs $X+ (X^top)^{-1}$ invertible for invertible $X$?Gauss-Seidel-method-Matrix has eigenvalue 0 and a claim about Gauss-Seidel convergencetensor power methodApproximation of a matrix in the power methodIterative method for a system of linear equations













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$begingroup$


Let $A in mathbb{R}^{n times n}$ be an invertible matrix. Consider the Schulz's method for fast computation of the inverse of $A$ given by:



$$
X_{k+1} = X_k + X_k (I -AX_k)
$$



where each $X_k in mathbb{R}^{n times n}$, and $X_0$ is such that $|A- AX_0| <1$.



Define $E_k=I -AX_k$. Then we know $E_{k+1}=E_k^2$ for all $k$, show that the sequence $(E_k)$ converges to zero matrix $Q$-quadratically.










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  • $begingroup$
    math.stackexchange.com/questions/1058476/…
    $endgroup$
    – Jean Marie
    yesterday
















1












$begingroup$


Let $A in mathbb{R}^{n times n}$ be an invertible matrix. Consider the Schulz's method for fast computation of the inverse of $A$ given by:



$$
X_{k+1} = X_k + X_k (I -AX_k)
$$



where each $X_k in mathbb{R}^{n times n}$, and $X_0$ is such that $|A- AX_0| <1$.



Define $E_k=I -AX_k$. Then we know $E_{k+1}=E_k^2$ for all $k$, show that the sequence $(E_k)$ converges to zero matrix $Q$-quadratically.










share|cite|improve this question











$endgroup$












  • $begingroup$
    math.stackexchange.com/questions/1058476/…
    $endgroup$
    – Jean Marie
    yesterday














1












1








1





$begingroup$


Let $A in mathbb{R}^{n times n}$ be an invertible matrix. Consider the Schulz's method for fast computation of the inverse of $A$ given by:



$$
X_{k+1} = X_k + X_k (I -AX_k)
$$



where each $X_k in mathbb{R}^{n times n}$, and $X_0$ is such that $|A- AX_0| <1$.



Define $E_k=I -AX_k$. Then we know $E_{k+1}=E_k^2$ for all $k$, show that the sequence $(E_k)$ converges to zero matrix $Q$-quadratically.










share|cite|improve this question











$endgroup$




Let $A in mathbb{R}^{n times n}$ be an invertible matrix. Consider the Schulz's method for fast computation of the inverse of $A$ given by:



$$
X_{k+1} = X_k + X_k (I -AX_k)
$$



where each $X_k in mathbb{R}^{n times n}$, and $X_0$ is such that $|A- AX_0| <1$.



Define $E_k=I -AX_k$. Then we know $E_{k+1}=E_k^2$ for all $k$, show that the sequence $(E_k)$ converges to zero matrix $Q$-quadratically.







linear-algebra numerical-linear-algebra






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share|cite|improve this question













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share|cite|improve this question








edited yesterday









Jean Marie

30.5k42154




30.5k42154










asked 2 days ago









SepideSepide

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4188












  • $begingroup$
    math.stackexchange.com/questions/1058476/…
    $endgroup$
    – Jean Marie
    yesterday


















  • $begingroup$
    math.stackexchange.com/questions/1058476/…
    $endgroup$
    – Jean Marie
    yesterday
















$begingroup$
math.stackexchange.com/questions/1058476/…
$endgroup$
– Jean Marie
yesterday




$begingroup$
math.stackexchange.com/questions/1058476/…
$endgroup$
– Jean Marie
yesterday










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