A simple bug..
- To: mathgroup@smc.vnet.net
- Subject: [mg11985] A simple bug..
- From: rao@supermod.egr.uh.edu (Dr. Jagannatha Rao)
- Date: Fri, 17 Apr 1998 03:40:22 -0400
- Organization: University of Houston
I seem to have come across this simple and reproducible bug :
The error is in the last line of this post (the others are simply
reproducing my previous steps) where "h" is not being replaced.....
Mathematica 3.0 for NEXTSTEP Intel
Copyright 1988-97 Wolfram Research, Inc.
-- Motif graphics initialized --
In[1]:= phi={
1 - 3 (x/h)^2 + 2 (x/h)^3,
-x(1-x/h)^2,
3(x/h)^2 - 2 (x/h)^3,
-x( (x/h)^2 - (x/h))}
2 3 2 3 2
3 x 2 x x 2 3 x 2 x x x
Out[1]= {1 - ---- + ----, -(x (1 - -) ), ---- - ----, -(x (-(-) + --))}
2 3 h 2 3 h 2
h h h h h
In[2]:= k1[i_,j_]:=
Integrate[
( e in
D[phi[[i]],{x,2}]
D[phi[[j]],{x,2}]
), {x,0,h}] Syntax::newl: The
newline character after " ( e in "
is understood as a multiplication operator.
In[3]:= k1matrix=Table[k1[i,j], {i,4},{j,4}]
12 e in -6 e in -12 e in -6 e in
Out[3]= {{-------, -------, --------, -------},
3 2 3 2
h h h h
-6 e in 4 e in 6 e in 2 e in -12 e in 6 e in 12 e in 6 e in
> {-------, ------, ------, ------}, {--------, ------, -------,
------},
2 h 2 h 3 2 3 2
h h h h h h
-6 e in 2 e in 6 e in 4 e in
> {-------, ------, ------, ------}}
2 h 2 h
h h
In[4]:= k1matrix=Table[k1[i,j], {i,4},{j,4}] /. h->6
e in -(e in) -(e in) -(e in) -(e in) 2 e in e in e in
Out[4]= {{----, -------, -------, -------}, {-------, ------, ----, ----},
18 6 18 6 6 3 6 3
-(e in) e in e in e in -(e in) e in e in 2 e in
> {-------, ----, ----, ----}, {-------, ----, ----, ------}}
18 6 18 6 6 3 6 3
In[5]:= k1matrix=Table[k1[i,j], {i,4},{j,4}] /. e*in -> 10^6
12000000 -6000000 -12000000 -6000000
Out[5]= {{--------, --------, ---------, --------},
3 2 3 2
h h h h
-6000000 4000000 6000000 2000000
> {--------, -------, -------, -------},
2 h 2 h
h h
-12000000 6000000 12000000 6000000
> {---------, -------, --------, -------},
3 2 3 2
h h h h
-6000000 2000000 6000000 4000000
> {--------, -------, -------, -------}}
2 h 2 h
h h
In[6]:= k1matrix=Table[k1[i,j], {i,4},{j,4}] /. {h->6, e*in ->10^6}
12000000 -6000000 -12000000 -6000000
Out[6]= {{--------, --------, ---------, --------},
3 2 3 2
h h h h
-6000000 4000000 6000000 2000000
> {--------, -------, -------, -------},
2 h 2 h
h h
-12000000 6000000 12000000 6000000
> {---------, -------, --------, -------},
3 2 3 2
h h h h
-6000000 2000000 6000000 4000000
> {--------, -------, -------, -------}}
2 h 2 h
h h
In[7]:=
--
Jagannatha Rao E-mail:rao@uh.edu
Associate Professor
Department of Mechanical Engineering Tel :(713) 743-4535 University
of Houston Fax :(713) 743-4503 Houston, TX
77204-4792