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KNAnagnostopoulos
New Contributor I
103 Views

ScaLAPACK: pzheev error 706: (eigenvalue computation) needs MB=NB

UPDATE: sorry, my mistake, it IS in the documentation:

*  Alignment requirements
*  ======================
*
*  The distributed submatrices A(IA:*, JA:*) and C(IC:IC+M-1,JC:JC+N-1)
*  must verify some alignment properties, namely the following
*  expressions should be true:
*
*  ( MB_A.EQ.NB_A.EQ.MB_Z .AND. IROFFA.EQ.IROFFZ .AND. IROFFA.EQ.0 .AND.
*    IAROW.EQ.IZROW )
*  where
*  IROFFA = MOD( IA-1, MB_A ) and ICOFFA = MOD( JA-1, NB_A ).

 

---------------------------------------

The following is missing in the documentation of pzheev and one has to look into the source code in order to understand the error:

The blocking factors of the matrix to be diagonalized must be equal, otherwise one obtains an error with INFO= -706 (error in the 6th element of the DESCA array). This error originates from the source code lines in pzheev.f: (line 446 in the version that I have)

           ELSE IF( DESCA( MB_ ).NE.DESCA( NB_ ) ) THEN

               INFO = -( 700+NB_ )
           END IF

The message is in order to help others with the same problem and/or the people who maintain the documentation of pzheev.

 

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1 Reply
Gennady_F_Intel
Moderator
103 Views

thanks for the notes. we will check and update the documentation.

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