Self join not permitted in Updates

    Local temporary tables are created in the V_TEMP_SCHEMA namespace and inserted into the user's search path transparently. Each local temporary table is visible only to the user who creates it, and only for the duration of the session in which the table is created.    When the session ends, HP Vertica automatically drops the table definition from the database catalogs. You cannot preserve non-empty, session-scoped temporary tables using the ON COMMIT PRESERVE ROWS statement.    Creating local temporary tables is significantly faster than creating regular tables, so you should make use of them whenever possible.Local Temporary Tables

any update on this, as still today i'm getting this error:
I'm Using Vertica Analytic Database v6.1.2-0

Still true in Vertica 9.2:

dbadmin=> SELECT version();
              version
------------------------------------
 Vertica Analytic Database v9.2.0-4
(1 row)

dbadmin=> SELECT * FROM test;
 c1
----
  1
  2
(2 rows)

dbadmin=> UPDATE test
dbadmin->    SET c1 = t2.c1 * 2
dbadmin->   FROM test t2
dbadmin->  WHERE t2.c1 = test.c1
dbadmin->    AND test.c1 = 2;
ERROR 4680:  Self joins in UPDATE statements are not allowed
DETAIL:  Target relation public.test also appears in the FROM list

But you could do this:

dbadmin=> UPDATE test
dbadmin->    SET c1 = t2.c1 * 2
dbadmin->   FROM (SELECT * FROM test) t2
dbadmin->  WHERE t2.c1 = test.c1
dbadmin->    AND test.c1 = 2;
 OUTPUT
--------
      1
(1 row)

dbadmin=> SELECT * FROM test;
 c1
----
  1
  4
(2 rows)

Although, why not just run this?

dbadmin=> UPDATE test SET c1 = c1 * 2 WHERE c1 = 4;
 OUTPUT
--------
      1
(1 row)

dbadmin=> SELECT * FROM test;
 c1
----
  1
  8
(2 rows)

Thanks for the update, I have solved this with MERGE statement
Your first solution will also work.

My use case was to add a column in table
which will have data from previous row like below:

Before update:
c1 c2

1 NULL
2 NULL
3 NULL
4 NULL

After update:
c1 c2

1 NULL
2 1
3 2
4 3