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<HTML>
<HEAD><TITLE>MA02HD - SLICOT Library Routine Documentation</TITLE>
</HEAD>
<BODY>
<H2><A Name="MA02HD">MA02HD</A></H2>
<H3>
Check if a matrix is a scalar multiple of an identity-like matrix
</H3>
<A HREF ="#Specification"><B>[Specification]</B></A>
<A HREF ="#Arguments"><B>[Arguments]</B></A>
<A HREF ="#Method"><B>[Method]</B></A>
<A HREF ="#References"><B>[References]</B></A>
<A HREF ="#Comments"><B>[Comments]</B></A>
<A HREF ="#Example"><B>[Example]</B></A>
<P>
<B><FONT SIZE="+1">Purpose</FONT></B>
<PRE>
To check if A = DIAG*I, where I is an M-by-N matrix with ones on
the diagonal and zeros elsewhere.
</PRE>
<A name="Specification"><B><FONT SIZE="+1">Specification</FONT></B></A>
<PRE>
LOGICAL FUNCTION MA02HD( JOB, M, N, DIAG, A, LDA )
C .. Scalar Arguments ..
CHARACTER JOB
INTEGER LDA, M, N
DOUBLE PRECISION DIAG
C .. Array Arguments ..
DOUBLE PRECISION A(LDA,*)
</PRE>
<B><FONT SIZE="+1">Function Value</FONT></B>
<PRE>
MA02HD LOGICAL
The function value is set to .TRUE. if A = DIAG*I, and to
.FALSE., otherwise. If min(M,N) = 0, the value is .FALSE.
</PRE>
<A name="Arguments"><B><FONT SIZE="+1">Arguments</FONT></B></A>
<P>
<B>Mode Parameters</B>
<PRE>
JOB CHARACTER*1
Specifies the part of the matrix A to be checked out,
as follows:
= 'U': Upper triangular/trapezoidal part;
= 'L': Lower triangular/trapezoidal part.
Otherwise: All of the matrix A.
</PRE>
<B>Input/Output Parameters</B>
<PRE>
M (input) INTEGER
The number of rows of the matrix A. M >= 0.
N (input) INTEGER
The number of columns of the matrix A. N >= 0.
DIAG (input) DOUBLE PRECISION
The scalar DIAG.
A (input) DOUBLE PRECISION array, dimension (LDA,N)
The leading M-by-N part of this array must contain the
matrix A. If JOB = 'U', only the upper triangle or
trapezoid is accessed; if JOB = 'L', only the lower
triangle or trapezoid is accessed.
LDA INTEGER
The leading dimension of the array A. LDA >= max(1,M).
</PRE>
<A name="Method"><B><FONT SIZE="+1">Method</FONT></B></A>
<PRE>
The routine returns immediately after detecting a diagonal element
which differs from DIAG, or a nonzero off-diagonal element in the
searched part of A.
</PRE>
<A name="Comments"><B><FONT SIZE="+1">Further Comments</FONT></B></A>
<PRE>
None
</PRE>
<A name="Example"><B><FONT SIZE="+1">Example</FONT></B></A>
<P>
<B>Program Text</B>
<PRE>
None
</PRE>
<B>Program Data</B>
<PRE>
None
</PRE>
<B>Program Results</B>
<PRE>
None
</PRE>
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