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.