.TH im_inv 1 "April 1993" "Scilab Group" "Scilab Function"
.so man1/sci.an
.SH NAME
im_inv - inverse image
.SH CALLING SEQUENCE
.nf
[X,dim]=im_inv(A,B [,tol]) 
.fi
.SH PARAMETERS
.TP 10
A,B
: two real or complex matrices with equal number of columns
.TP
X
: orthogonal or unitary square matrix of order equal to the 
number of columns of \fVA\fR
.TP
dim
: integer (dimension of subspace)
.SH DESCRIPTION
.Vb [X,dim]=im_inv(A,B)
computes 
.IG
(A^-1)(B)
.FI
.LA $ A^{-1}(\cal B)$
 i.e vectors whose image through \fVA\fR are in range(\fVB\fR)
.LP
The \fVdim\fR first columns of \fVX\fR span 
.IG
(A^-1) (B)
.FI
.LA $ A^{-1}(\cal B).$
.LP
\fVtol\fR is a threshold used to test if subspace inclusion;
default value is \fVtol = 100*%eps\fR.
.SH SEE ALSO
rowcomp
.SH AUTHOR
F. D.