<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">
</head>
<body bgcolor="#ffffff" text="#000000">
<big><font size="-1"><big><big>Hi all, <br>
<br>
</big>I am having some problems using the subroutines opdiv and multd.<br>
For some reasons they do not give me correct results. <br>
Do they need any special treatment or precautions? <br>
<br>
I was trying to compute the divergence of a 3D field, and i realized
that </big></font></big><big><font size="-1"><big> in my case </big></font></big><big><font
size="-1"><big>the multd subroutine used <br>
by opdiv does not gives good results, while the same derivative
computed from gram1 gives no problems.<br>
<br>
For example, I overwrite an analytical field : <br>
<br>
...<br>
parameter(lt=lx1*ly1*lz1*lelt)<br>
real Res(lt)<br>
...<br>
vx(i,j,k,e)= 1.0*sin(x)*cos(y)*cos(z) <br>
...<br>
call print_line(vx) <br>
...<br>
iflg = 1<br>
call multd (RES(1),vx,rym2,sym2,tym2,2,iflg)<br>
call print_line(Res(1) )<br>
<br>
call gradm1(work1,Res(1),work2,vx)<br>
call print_line(Res(1) )<br>
...<br>
if (lx2.ne.lx1) then <br>
...<br>
STOP <br>
endif <br>
<br>
<br>
and print output a (xr,:,zr) the result (performed by </big></font><font
size="-1"><big>print_line) </big></font></big><font size="-1"><big>.<br>
In vxi.eps i compare the result (lines) with the analytical solution(
symbols). The result of multd is not correct while all <br>
the others match perfectly the analytical solution.<br>
In vxy.eps i plot only the result of multd. Note that on y i have 12
elements the same number of peaks of the solution. <br>
<br>
Does anybody have an idea on how to fix this?<br>
<br>
Thank you very much for any help or suggestion<br>
<br>
francesco</big><br>
<br>
<br>
<br>
</font>
</body>
</html>