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.TH fchamp 2 "April 1993" "Scilab Group" "Scilab Function"
.so ../sci.an
.SH NAME
fchamp - draw a 2d vector field
.SH CALLING SEQUENCE
.nf
fchamp(f,t,xr,yr,[arfact,brect,strf])
.fi
.SH PARAMETERS
.TP 10
f
: a function which describes the vector field.
.RS
.TP
-
It can be a function name \fVf\fR,
where \fVf\fR is supposed to be a function of type \fV[y]=f(t,x,[u])\fR ( \fVf\fR returns
a column vector of dimension 2, \fVy\fR, which gives the value of the vector field
\fVf\fR at point \fVx\fR and time \fVt\fR.
.TP
-
It can also be an object of type list,
\fVlist(f1,u1)\fR
where \fVf1\fR is a function (\fVf [y]=f1(t,x,u)\fR ) and \fVu1\fR gives the value of the parameter \fVu\fR.
.RE
.TP
t
: The selected time.
.TP
xr,yr
: two vectors of size (1,n1) (1,n2) which specifies the grid on which the vector field is to be computed.
.TP
arfact,brect,strf
: optional arguments, see \fVchamp\fR.
.SH DESCRIPTION
the \fVfchamp\fR is used to draw a two dimensional vector field described by a a Scilab
external.
Enter the command \fVchamp()\fR to see a demo.
.SH EXAMPLE
.nf
deff('[xdot] = derpol(t,x)',['xd1 = x(2)';
"xd2 = -x(1) + (1 - x(1)**2)*x(2)";
"xdot = [ xd1 ; xd2 ]"]);
xf= -1:0.1:1;
yf= -1:0.1:1;
fchamp(derpol,0,xf,yf);
xbasc();
fchamp(derpol,0,xf,yf,1,[-2,-2,2,2],"011");
.fi
.SH AUTHOR
J.Ph.C.
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