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< H2 > < A NAME = "SECTION00086000000000000000" > < / A > < A NAME = "sec:precapply" > < / A >
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Method apply
< / H2 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < / BIG > < / BIG >
< P >
< BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < / BIG > < / BIG >
< DIV ALIGN = "CENTER" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < code > call p%apply(x,y,desc_a,info [,trans,work])< / code >
< BR > < / BIG > < / BIG > < / BIG > < / DIV > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < / BIG > < / BIG >
< P >
< BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" >
This method computes <!-- MATH
$y = op(B^{-1})\, x$
-->
< SPAN CLASS = "MATH" > < IMG
WIDTH="113" HEIGHT="39" ALIGN="MIDDLE" BORDER="0"
SRC="img86.png"
ALT="$y = op(B^{-1})\, x$">< / SPAN > , where < SPAN CLASS = "MATH" > < IMG
WIDTH="19" HEIGHT="15" ALIGN="BOTTOM" BORDER="0"
SRC="img24.png"
ALT="$B$">< / SPAN > is a previously built
preconditioner, stored into < code > p< / code > , and < SPAN CLASS = "MATH" > < IMG
WIDTH="21" HEIGHT="31" ALIGN="MIDDLE" BORDER="0"
SRC="img87.png"
ALT="$op$">< / SPAN >
denotes the preconditioner itself or its transpose, according to
the value of < code > trans< / code > .
Note that, when MLD2P4 is used with a Krylov solver from PSBLAS,
< code > p%apply< / code > is called within the PSBLAS method < code > psb_krylov< / code >
and hence it is completely transparent to the user.
< / BIG > < / BIG > < / BIG >
< P >
< BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < B > Arguments< / B > < / BIG > < / BIG > < / BIG > < / BIG >
< P > < / P >
< BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < / BIG > < / BIG >
< P >
< BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < / BIG > < / BIG > < TABLE CELLPADDING = 3 >
< TR > < TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 34 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" >
< code > x< / code > < / BIG > < / BIG > < / BIG > < / TD >
< TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 340 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < SPAN CLASS = "textit" > type< / SPAN > < code > (< / code > < SPAN CLASS = "textit" > kind_parameter< / SPAN > < code > ), dimension(:), intent(in)< / code > .< / BIG > < / BIG > < / BIG > < / TD >
< / TR >
< TR > < TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 34 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" >
< / BIG > < / BIG > < / BIG > < / TD >
< TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 340 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > The local part of the vector < SPAN CLASS = "MATH" > < IMG
WIDTH="15" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
SRC="img88.png"
ALT="$x$">< / SPAN > . Note that < SPAN CLASS = "textit" > type< / SPAN > and
< SPAN CLASS = "textit" > kind_parameter< / SPAN > must be chosen according
to the real/complex, single/double precision version of MLD2P4 under use.< / BIG > < / BIG > < / BIG > < / TD >
< / TR >
< TR > < TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 34 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" >
< code > y< / code > < / BIG > < / BIG > < / BIG > < / TD >
< TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 340 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < SPAN CLASS = "textit" > type< / SPAN > < code > (< / code > < SPAN CLASS = "textit" > kind_parameter< / SPAN > < code > ), dimension(:), intent(out)< / code > .< / BIG > < / BIG > < / BIG > < / TD >
< / TR >
< TR > < TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 34 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" >
< / BIG > < / BIG > < / BIG > < / TD >
< TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 340 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > The local part of the vector < SPAN CLASS = "MATH" > < IMG
WIDTH="13" HEIGHT="31" ALIGN="MIDDLE" BORDER="0"
SRC="img89.png"
ALT="$y$">< / SPAN > . Note that < SPAN CLASS = "textit" > type< / SPAN > and
< SPAN CLASS = "textit" > kind_parameter< / SPAN > must be chosen according
to the real/complex, single/double precision version of MLD2P4 under use.< / BIG > < / BIG > < / BIG > < / TD >
< / TR >
< TR > < TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 34 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" >
< code > desc_a< / code > < / BIG > < / BIG > < / BIG > < / TD >
< TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 340 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < code > type(psb_desc_type), intent(in)< / code > . < / BIG > < / BIG > < / BIG > < / TD >
< / TR >
< TR > < TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 34 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" >
< / BIG > < / BIG > < / BIG > < / TD >
< TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 340 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > The communication descriptor associated to the matrix to be
preconditioned.< / BIG > < / BIG > < / BIG > < / TD >
< / TR >
< TR > < TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 34 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" >
< code > info< / code > < / BIG > < / BIG > < / BIG > < / TD >
< TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 340 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < code > integer, intent(out)< / code > .< / BIG > < / BIG > < / BIG > < / TD >
< / TR >
< TR > < TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 34 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" >
< / BIG > < / BIG > < / BIG > < / TD >
< TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 340 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > Error code. If no error, 0 is returned. See Section < A HREF = "node34.html#sec:errors" > 8< / A > for details.< / BIG > < / BIG > < / BIG > < / TD >
< / TR >
< TR > < TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 34 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" >
< code > trans< / code > < / BIG > < / BIG > < / BIG > < / TD >
< TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 340 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < code > character(len=1), optional, intent(in).< / code > < / BIG > < / BIG > < / BIG > < / TD >
< / TR >
< TR > < TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 34 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" >
< / BIG > < / BIG > < / BIG > < / TD >
< TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 340 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > If < code > trans< / code > = < code > 'N','n'< / code > then <!-- MATH
$op(B^{-1}) = B^{-1}$
-->
< SPAN CLASS = "MATH" > < IMG
WIDTH="123" HEIGHT="39" ALIGN="MIDDLE" BORDER="0"
SRC="img90.png"
ALT="$op(B^{-1}) = B^{-1}$">< / SPAN > ;
if < code > trans< / code > = < code > 'T','t'< / code > then <!-- MATH
$op(B^{-1}) = B^{-T}$
-->
< SPAN CLASS = "MATH" > < IMG
WIDTH="126" HEIGHT="40" ALIGN="MIDDLE" BORDER="0"
SRC="img91.png"
ALT="$op(B^{-1}) = B^{-T}$">< / SPAN >
(transpose of < SPAN CLASS = "MATH" > < IMG
WIDTH="44" HEIGHT="39" ALIGN="MIDDLE" BORDER="0"
SRC="img92.png"
ALT="$B^{-1})$">< / SPAN > ; if < code > trans< / code > = < code > 'C','c'< / code > then <!-- MATH
$op(B^{-1}) = B^{-C}$
-->
< SPAN CLASS = "MATH" > < IMG
WIDTH="126" HEIGHT="40" ALIGN="MIDDLE" BORDER="0"
SRC="img93.png"
ALT="$op(B^{-1}) = B^{-C}$">< / SPAN >
(conjugate transpose of < SPAN CLASS = "MATH" > < IMG
WIDTH="44" HEIGHT="39" ALIGN="MIDDLE" BORDER="0"
SRC="img92.png"
ALT="$B^{-1})$">< / SPAN > .< / BIG > < / BIG > < / BIG > < / TD >
< / TR >
< TR > < TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 34 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" >
< code > work< / code > < / BIG > < / BIG > < / BIG > < / TD >
< TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 340 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < SPAN CLASS = "textit" > type< / SPAN > < code > (< / code > < SPAN CLASS = "textit" > kind_parameter< / SPAN > < code > ), dimension(:), optional, target< / code > .< / BIG > < / BIG > < / BIG > < / TD >
< / TR >
< TR > < TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 34 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" >
< / BIG > < / BIG > < / BIG > < / TD >
< TD ALIGN = "LEFT" VALIGN = "TOP" WIDTH = 340 > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > Workspace. Its size should be at
least < code > 4 * psb_cd_get_local_< / code > < code > cols(desc_a)< / code > (see the PSBLAS User's Guide).
Note that < SPAN CLASS = "textit" > type< / SPAN > and < SPAN CLASS = "textit" > kind_parameter< / SPAN > must be chosen according
to the real/complex, single/double precision version of MLD2P4 under use.< / BIG > < / BIG > < / BIG > < / TD >
< / TR >
< / TABLE > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < / BIG > < / BIG >
< P >
< BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > For compatibility with the previous versions of MLD2P4, this method can be also invoked
as follows:
< / BIG > < / BIG > < / BIG >
< P >
< BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < / BIG > < / BIG >
< DIV ALIGN = "CENTER" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < code > call mld_precaply(p,what,val,info)< / code >
< / BIG > < / BIG > < / BIG > < / DIV > < BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < / BIG > < / BIG >
< P >
< BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < / BIG > < / BIG >
< P >
< BIG CLASS = "LARGE" > < BIG CLASS = "LARGE" > < / BIG > < / BIG >
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