lacon#

Functions

void slacon(
    const INT           n,
          f32* restrict V,
          f32* restrict X,
          INT* restrict ISGN,
          f32*          est,
          INT*          kase
);
void slacon(const INT n, f32 *restrict V, f32 *restrict X, INT *restrict ISGN, f32 *est, INT *kase)#

SLACON estimates the 1-norm of a square, real matrix A.

Reverse communication is used for evaluating matrix-vector products.

Parameters

in
n

The order of the matrix. n >= 1.

out
V

Double precision array, dimension (n). On the final return, V = A*W, where EST = norm(V)/norm(W) (W is not returned).

inout
X

Double precision array, dimension (n). On an intermediate return, X should be overwritten by A * X, if kase=1, A**T * X, if kase=2, and SLACON must be re-called with all the other parameters unchanged.

out
ISGN

Integer array, dimension (n).

inout
est

On entry with kase = 1 or 2 and jump = 3, est should be unchanged from the previous call to SLACON. On exit, est is an estimate (a lower bound) for norm(A).

inout
kase

On the initial call to SLACON, kase should be 0. On an intermediate return, kase will be 1 or 2, indicating whether X should be overwritten by A * X or A**T * X. On the final return from SLACON, kase will again be 0.

Functions

void dlacon(
    const INT           n,
          f64* restrict V,
          f64* restrict X,
          INT* restrict ISGN,
          f64*          est,
          INT*          kase
);
void dlacon(const INT n, f64 *restrict V, f64 *restrict X, INT *restrict ISGN, f64 *est, INT *kase)#

DLACON estimates the 1-norm of a square, real matrix A.

Reverse communication is used for evaluating matrix-vector products.

Parameters

in
n

The order of the matrix. n >= 1.

out
V

Double precision array, dimension (n). On the final return, V = A*W, where EST = norm(V)/norm(W) (W is not returned).

inout
X

Double precision array, dimension (n). On an intermediate return, X should be overwritten by A * X, if kase=1, A**T * X, if kase=2, and DLACON must be re-called with all the other parameters unchanged.

out
ISGN

Integer array, dimension (n).

inout
est

On entry with kase = 1 or 2 and jump = 3, est should be unchanged from the previous call to DLACON. On exit, est is an estimate (a lower bound) for norm(A).

inout
kase

On the initial call to DLACON, kase should be 0. On an intermediate return, kase will be 1 or 2, indicating whether X should be overwritten by A * X or A**T * X. On the final return from DLACON, kase will again be 0.

Functions

void clacon(
    const INT           n,
          c64* restrict V,
          c64* restrict X,
          f32*          est,
          INT*          kase
);
void clacon(const INT n, c64 *restrict V, c64 *restrict X, f32 *est, INT *kase)#

CLACON estimates the 1-norm of a square, complex matrix A.

Reverse communication is used for evaluating matrix-vector products.

Parameters

in
n

The order of the matrix. n >= 1.

out
V

Complex*16 array, dimension (n). On the final return, V = A*W, where EST = norm(V)/norm(W) (W is not returned).

inout
X

Complex*16 array, dimension (n). On an intermediate return, X should be overwritten by A * X, if kase=1, A**H * X, if kase=2, where A**H is the conjugate transpose of A, and CLACON must be re-called with all the other parameters unchanged.

inout
est

On entry with kase = 1 or 2 and jump = 3, est should be unchanged from the previous call to CLACON. On exit, est is an estimate (a lower bound) for norm(A).

inout
kase

On the initial call to CLACON, kase should be 0. On an intermediate return, kase will be 1 or 2, indicating whether X should be overwritten by A * X or A**H * X. On the final return from CLACON, kase will again be 0.

Functions

void zlacon(
    const INT            n,
          c128* restrict V,
          c128* restrict X,
          f64*           est,
          INT*           kase
);
void zlacon(const INT n, c128 *restrict V, c128 *restrict X, f64 *est, INT *kase)#

ZLACON estimates the 1-norm of a square, complex matrix A.

Reverse communication is used for evaluating matrix-vector products.

Parameters

in
n

The order of the matrix. n >= 1.

out
V

Complex*16 array, dimension (n). On the final return, V = A*W, where EST = norm(V)/norm(W) (W is not returned).

inout
X

Complex*16 array, dimension (n). On an intermediate return, X should be overwritten by A * X, if kase=1, A**H * X, if kase=2, where A**H is the conjugate transpose of A, and ZLACON must be re-called with all the other parameters unchanged.

inout
est

On entry with kase = 1 or 2 and jump = 3, est should be unchanged from the previous call to ZLACON. On exit, est is an estimate (a lower bound) for norm(A).

inout
kase

On the initial call to ZLACON, kase should be 0. On an intermediate return, kase will be 1 or 2, indicating whether X should be overwritten by A * X or A**H * X. On the final return from ZLACON, kase will again be 0.

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