p?lacon

Developer Reference for Intel® oneAPI Math Kernel Library for C

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ID 766684

Date 12/16/2022

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p?lacon

Estimates the 1-norm of a square matrix, using the reverse communication for evaluating matrix-vector products.

Syntax

void pslacon (MKL_INT *n , float *v , MKL_INT *iv , MKL_INT *jv , MKL_INT *descv , float *x , MKL_INT *ix , MKL_INT *jx , MKL_INT *descx , MKL_INT *isgn , float *est , MKL_INT *kase );

void pdlacon (MKL_INT *n , double *v , MKL_INT *iv , MKL_INT *jv , MKL_INT *descv , double *x , MKL_INT *ix , MKL_INT *jx , MKL_INT *descx , MKL_INT *isgn , double *est , MKL_INT *kase );

void pclacon (MKL_INT *n , MKL_Complex8 *v , MKL_INT *iv , MKL_INT *jv , MKL_INT *descv , MKL_Complex8 *x , MKL_INT *ix , MKL_INT *jx , MKL_INT *descx , float *est , MKL_INT *kase );

void pzlacon (MKL_INT *n , MKL_Complex16 *v , MKL_INT *iv , MKL_INT *jv , MKL_INT *descv , MKL_Complex16 *x , MKL_INT *ix , MKL_INT *jx , MKL_INT *descx , double *est , MKL_INT *kase );

Include Files

mkl_scalapack.h

Description

The p?laconfunction estimates the 1-norm of a square, real/unitary distributed matrix A. Reverse communication is used for evaluating matrix-vector products. x and v are aligned with the distributed matrix A, this information is implicitly contained within iv, ix, descv, and descx.

Input Parameters

n

(global) The length of the distributed vectors v and x. n ≥ 0.

v

(local).

Pointer into the local memory to an array of size LOCr(n+mod(iv-1, mb_v)). On the final return, v = a*w, where est = norm(v)/norm(w) (w is not returned).

iv, jv

(global) The row and column indices in the global matrix V indicating the first row and the first column of the submatrix V, respectively.

descv

(global and local) array of size dlen_. The array descriptor for the distributed matrix V.

x

(local).

Pointer into the local memory to an array of size LOCr(n+mod(ix-1, mb_x)).

ix, jx

(global) The row and column indices in the global matrix X indicating the first row and the first column of the submatrix X, respectively.

descx

(global and local) array of size dlen_. The array descriptor for the distributed matrix X.

isgn

(local).

Array of size LOCr(n+mod(ix-1, mb_x)). isgn is aligned with x and v.

kase

(local).

On the initial call to p?lacon, kase should be 0.

Output Parameters

x

(local).

On an intermediate return, X should be overwritten by A*X, if kase=1, A' *X, if kase=2,

p?lacon must be re-called with all the other parameters unchanged.

est

(global).

kase

(local)

On an intermediate return, kase is 1 or 2, indicating whether X should be overwritten by A*X, or A'*X. On the final return from p?lacon, kase is again 0.

Parent topic: ScaLAPACK Auxiliary Routines

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p?lacon

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