ML_DGECON – Estimates the reciprocal of the condition number of a general real matrix

Block SymbolLicensing group: MATRIX
PIC

Function Description
The output references yA, yWORK and yIWORK are always set to the corresponding input references uA, uWORK and uIWORK. If HLD = on then nothing is computed otherwise the LAPACK function DGECON is called internally:

DGECON(sINORM, N, uA, LDA, anorm, rcond, uWORK, uIWORK, info);

where parameters of DGECON are set in the following way:

  • If INORM = on then the string sINORM is set to "I" else it is set to "1".
  • N is number of columns of the matrix referenced by uA.
  • LDA is the leading dimension of the matrix referenced by uA.
  • rcond is returned reciprocal value of the condition number of the matrix referenced by uA.
  • info is return code from the function DGECON.

The error flag E is set to on if:

  • the reference uA or uWORK or uIWORK is not defined (i.e. input uA or uWORK or uIWORK is not connected),
  • the matrix referenced by uA is not square,
  • number of elements of the vector referenced by uWORK is less than 4 N,
  • number of elements of the integer vector referenced by uIWORK is less than N,
  • the call of the function DGECON returns error using the function XERBLA, see the return code info and system log.

See LAPACK documentation [7] for more details.

Inputs

uA

Input reference to matrix A

Reference

uWORK

Input reference to working vector WORK

Reference

uIWORK

Input reference to integer working vector WORK

Reference

INORM

Use Infinity-norm

Bool

anorm

Norm of the original matrix A  0.0

Double (F64)

HLD

Hold

Bool

Outputs

yA

Output reference to matrix A

Reference

yWORK

Output reference to working vector WORK

Reference

yIWORK

Output reference to integer working vector WORK

Reference

rcond

The reciprocal of the condition number of the matrix A

Double (F64)

E

Error indicator

Bool

info

LAPACK function result info. If info = -i, the i=th argument had an illegal value

Long (I32)

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