SAS Note V6-IML-H005

From: SAS Technical Support (LISTSERV@VM.SAS.COM)
Date: Mon Mar 11 2002 - 07:58:44 EST

  • Next message: SAS Technical Support: "SAS Institute Alert Note SN-007089"

    V6-IML-H005 ***Alert Note***

    CALL SVD, GINV and HOMOGEN functions may return incorrect results

    Product: IML
    Component: IML
    Priority: ALERT

      In some instances the results returned by CALL SVD and the GINV
      and HOMOGEN functions may be incorrect. To see if you are at risk for
      encountering this problem, use the following check:

         PROC IML;
            START SVDCHK(A,U,S,V);
               SSA=SSQ(A); SSS=SSQ(S);
               B=U*DIAG(S)*V`;
               N=NROW(S);
               EPS=CONSTANT('sqrtmaceps');
               IF MAX(ABS(A-B)) > EPS * MAX(ABS(A))
                  | MAX(ABS(U`*U)-I(N)) > EPS
                  | MAX(ABS(V`*V)-I(N)) > EPS
                  | ABS(SSA-SSS) > EPS * MAX(SSA,SSS)
               THEN DO;
                  PRINT 'Problem Encountered', A;
               ELSE DO;
                  PRINT 'OK';
               END; RETURN;
            FINISH;

    Keywords:
      iml incorrout incorrstat call svd incorrect
      H005

    SAS Note Revised On: Fri, 8 Mar 2002

    System Release Reported Release Fixed

    AIX/6000 6.12 TS020
    HP-UX Operating Systems 6.12 TS020
    IBM OS/2 6.12 TS020
    Solaris 6.12 TS020
    OpenVMS Alpha 6.12 TS020
    Windows 3.11 6.12 TS020
    Windows NT 6.12 TS020
    Windows 95 6.12 TS020
    Compaq Tru64 Unix 6.12 TS040
    Macintosh 6.12 TS040

    No Fixes Available

    +-------------------------------------------------------------------------
    + NOTE: To unsubscribe you can reply to this mail with:
    + "SIGNOFF tsnews-l"
    + as the only text in the body of the message (without the double quotes).
    + If you have any questions please send them to SUPPORT@SAS.COM
    +-------------------------------------------------------------------------



    This archive was generated by hypermail 2b29 : Mon Mar 11 2002 - 07:59:39 EST