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Diffstat (limited to '2.3-1/src/fortran/lapack/zlange.f')
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diff --git a/2.3-1/src/fortran/lapack/zlange.f b/2.3-1/src/fortran/lapack/zlange.f new file mode 100644 index 00000000..36cecbdc --- /dev/null +++ b/2.3-1/src/fortran/lapack/zlange.f @@ -0,0 +1,145 @@ + DOUBLE PRECISION FUNCTION ZLANGE( NORM, M, N, A, LDA, WORK ) +* +* -- LAPACK auxiliary routine (version 3.1) -- +* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. +* November 2006 +* +* .. Scalar Arguments .. + CHARACTER NORM + INTEGER LDA, M, N +* .. +* .. Array Arguments .. + DOUBLE PRECISION WORK( * ) + COMPLEX*16 A( LDA, * ) +* .. +* +* Purpose +* ======= +* +* ZLANGE returns the value of the one norm, or the Frobenius norm, or +* the infinity norm, or the element of largest absolute value of a +* complex matrix A. +* +* Description +* =========== +* +* ZLANGE returns the value +* +* ZLANGE = ( max(abs(A(i,j))), NORM = 'M' or 'm' +* ( +* ( norm1(A), NORM = '1', 'O' or 'o' +* ( +* ( normI(A), NORM = 'I' or 'i' +* ( +* ( normF(A), NORM = 'F', 'f', 'E' or 'e' +* +* where norm1 denotes the one norm of a matrix (maximum column sum), +* normI denotes the infinity norm of a matrix (maximum row sum) and +* normF denotes the Frobenius norm of a matrix (square root of sum of +* squares). Note that max(abs(A(i,j))) is not a consistent matrix norm. +* +* Arguments +* ========= +* +* NORM (input) CHARACTER*1 +* Specifies the value to be returned in ZLANGE as described +* above. +* +* M (input) INTEGER +* The number of rows of the matrix A. M >= 0. When M = 0, +* ZLANGE is set to zero. +* +* N (input) INTEGER +* The number of columns of the matrix A. N >= 0. When N = 0, +* ZLANGE is set to zero. +* +* A (input) COMPLEX*16 array, dimension (LDA,N) +* The m by n matrix A. +* +* LDA (input) INTEGER +* The leading dimension of the array A. LDA >= max(M,1). +* +* WORK (workspace) DOUBLE PRECISION array, dimension (MAX(1,LWORK)), +* where LWORK >= M when NORM = 'I'; otherwise, WORK is not +* referenced. +* +* ===================================================================== +* +* .. Parameters .. + DOUBLE PRECISION ONE, ZERO + PARAMETER ( ONE = 1.0D+0, ZERO = 0.0D+0 ) +* .. +* .. Local Scalars .. + INTEGER I, J + DOUBLE PRECISION SCALE, SUM, VALUE +* .. +* .. External Functions .. + LOGICAL LSAME + EXTERNAL LSAME +* .. +* .. External Subroutines .. + EXTERNAL ZLASSQ +* .. +* .. Intrinsic Functions .. + INTRINSIC ABS, MAX, MIN, SQRT +* .. +* .. Executable Statements .. +* + IF( MIN( M, N ).EQ.0 ) THEN + VALUE = ZERO + ELSE IF( LSAME( NORM, 'M' ) ) THEN +* +* Find max(abs(A(i,j))). +* + VALUE = ZERO + DO 20 J = 1, N + DO 10 I = 1, M + VALUE = MAX( VALUE, ABS( A( I, J ) ) ) + 10 CONTINUE + 20 CONTINUE + ELSE IF( ( LSAME( NORM, 'O' ) ) .OR. ( NORM.EQ.'1' ) ) THEN +* +* Find norm1(A). +* + VALUE = ZERO + DO 40 J = 1, N + SUM = ZERO + DO 30 I = 1, M + SUM = SUM + ABS( A( I, J ) ) + 30 CONTINUE + VALUE = MAX( VALUE, SUM ) + 40 CONTINUE + ELSE IF( LSAME( NORM, 'I' ) ) THEN +* +* Find normI(A). +* + DO 50 I = 1, M + WORK( I ) = ZERO + 50 CONTINUE + DO 70 J = 1, N + DO 60 I = 1, M + WORK( I ) = WORK( I ) + ABS( A( I, J ) ) + 60 CONTINUE + 70 CONTINUE + VALUE = ZERO + DO 80 I = 1, M + VALUE = MAX( VALUE, WORK( I ) ) + 80 CONTINUE + ELSE IF( ( LSAME( NORM, 'F' ) ) .OR. ( LSAME( NORM, 'E' ) ) ) THEN +* +* Find normF(A). +* + SCALE = ZERO + SUM = ONE + DO 90 J = 1, N + CALL ZLASSQ( M, A( 1, J ), 1, SCALE, SUM ) + 90 CONTINUE + VALUE = SCALE*SQRT( SUM ) + END IF +* + ZLANGE = VALUE + RETURN +* +* End of ZLANGE +* + END |