RE: A simple bug..
- To: mathgroup@smc.vnet.net
- Subject: [mg12029] RE: [mg11985] A simple bug..
- From: "jmt" <jmthomas@cybercable.tm.fr>
- Date: Fri, 24 Apr 1998 01:52:03 -0400
If you want to replace h PERMANENTLY use h=6 See also help for Set, Replace and ReplaceAll. Hope this helps, **************************************** Jean-Marie THOMAS Conseil et Audit en Inginierie de Calcul Strasbourg, France **************************************** -----Original Message----- From: Dr. Jagannatha Rao [mailto:rao@supermod.egr.uh.edu] To: mathgroup@smc.vnet.net Subject: [mg12029] [mg11985] A simple bug.. 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