Subject: a package of functions for vector analysis.
From: 品部 宗博
Date: Fri, 1 Apr 2011 20:27:30 +0900
we have two questions.
1)I loaded the package of ("vect") .but the dot operator "." was not a commutative operator as the following mentioned below.
Documentation Categories tell "Warning: the vect package declares the dot operator . to be a commutative operator."
Please teach me the reason.
(%i1)kill(all)$
load(vect)$
declare([ f, g,p,q], nonscalar) $
f .g-g .f ;
declare(".",commutative);
f .g-g .f ;
(%o3) f . g-g . f
(%o4) done
(%o5) 0
2) I try "demo(vect);",but that didn't operate.Why?
demo(vect);
read and interpret file: #pC:/PROGRA~1/MAXIMA~1.2/share/maxima/5.23.2/share/vector/vect.dem
At the '_' prompt, type ';' and <enter> to get next demonstration.
(%i2) if get('vect,'version)=false then load("vect")
_
********************************************************************************
5.23.2 Manual:25
Documentation Categories
25. Matrices and Linear Algebra
25.1.2 Vectors
vect is a package of functions for vector analysis. load ("vect") loads this package,
and demo ("vect") displays a demonstration. The vector analysis package can combine
and simplify symbolic expressions including dot products and cross products,
together with the gradient, divergence, curl, and Laplacian operators.
The distribution of these operators over sums or products is governed by several
flags, as are various other expansions, including expansion into components in any
specific orthogonal coordinate systems. There are also functions for deriving the
scalar or vector potential of a field.
The vect package contains these functions: vectorsimp, scalefactors, express, potential,
and vectorpotential.
Warning: the vect package declares the dot operator . to be a commutative operator.