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SUBROUTINE DLADIV( A, B, C, D, P, Q )
*
* -- LAPACK auxiliary routine (version 3.1) --
* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
* November 2006
*
* .. Scalar Arguments ..
DOUBLE PRECISION A, B, C, D, P, Q
* ..
*
* Purpose
* =======
*
* DLADIV performs complex division in real arithmetic
*
* a + i*b
* p + i*q = ---------
* c + i*d
*
* The algorithm is due to Robert L. Smith and can be found
* in D. Knuth, The art of Computer Programming, Vol.2, p.195
*
* Arguments
* =========
*
* A (input) DOUBLE PRECISION
* B (input) DOUBLE PRECISION
* C (input) DOUBLE PRECISION
* D (input) DOUBLE PRECISION
* The scalars a, b, c, and d in the above expression.
*
* P (output) DOUBLE PRECISION
* Q (output) DOUBLE PRECISION
* The scalars p and q in the above expression.
*
* =====================================================================
*
* .. Local Scalars ..
DOUBLE PRECISION E, F
* ..
* .. Intrinsic Functions ..
INTRINSIC ABS
* ..
* .. Executable Statements ..
*
IF( ABS( D ).LT.ABS( C ) ) THEN
E = D / C
F = C + D*E
P = ( A+B*E ) / F
Q = ( B-A*E ) / F
ELSE
E = C / D
F = D + C*E
P = ( B+A*E ) / F
Q = ( -A+B*E ) / F
END IF
*
RETURN
*
* End of DLADIV
*
END
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