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ML_DGEEV – Computes the eigenvalues and, optionally, the left and/or right eigenvectors

Block SymbolLicensing group: MATRIX
PIC

Function Description
The output references yA, yWR, yWI, yVL, yVR and yWORK are always set to the corresponding input references uA, uWR, uWI, uVL, uVR and uWORK. If HLD = on then nothing is computed otherwise the LAPACK function DGEEV is called internally:

DGEEV(sJOBVL, sJOBVR, N, uA, LDA, uWR, uWI, uVL, LDVL, uVR, LDVR,
uWORK, LWORK, info);

where parameters of DGEEV are set in the following way:

  • If JOBVL = on then the string sJOBVL is set to "V" else it is set to "N".
  • If JOBVR = on then the string sJOBVR is set to "V" else it is set to "N".
  • N is number of columns of the matrix referenced by uA.
  • LDA, LDVL and LDVR are leading dimensions of the matrices referenced by uA, uVL and uVR.
  • LWORK is number of elements of the vector referenced by uWORK.
  • info is return code from the function DGEEV.

The error flag E is set to on if:

  • the reference uA or uWR or uWI or uVL or uVR or uWORK is not defined (i.e. input uA or uWR or uWI or uVL or uVR or uWORK is not connected),
  • the matrix referenced by uA is not square,
  • number of elements of vectors referenced by uWR or uWI is less than N,
  • number of columns of matrices referenced by uVL or uVR is not equal to N,
  • the call of the function DGEEV 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

uWR

Input reference to vector of real parts of eigenvalues

Reference

uWI

Input reference to vector of imaginary parts of eigenvalues

Reference

uVL

Input reference to matrix of left eigenvectors

Reference

uVR

Input reference to matrix of right eigenvectors

Reference

uWORK

Input reference to working vector WORK

Reference

JOBVL

If true then left eigenvectors are computed

Bool

JOBVR

If true then right eigenvectors are computed

Bool

HLD

Hold

Bool

Outputs

yA

Output reference to matrix A

Reference

yWR

Output reference to vector of real parts of eigenvalues

Reference

yWI

Output reference to vector of imaginary parts of eigenvalues

Reference

yVL

Output reference to VL

Reference

yVR

Output reference to VR

Reference

yWORK

Output reference to working vector WORK

Reference

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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