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Mise à jour de lapack vers la version 3.3.0.
1: SUBROUTINE DPTSV( N, NRHS, D, E, B, LDB, INFO ) 2: * 3: * -- LAPACK routine (version 3.2) -- 4: * -- LAPACK is a software package provided by Univ. of Tennessee, -- 5: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- 6: * November 2006 7: * 8: * .. Scalar Arguments .. 9: INTEGER INFO, LDB, N, NRHS 10: * .. 11: * .. Array Arguments .. 12: DOUBLE PRECISION B( LDB, * ), D( * ), E( * ) 13: * .. 14: * 15: * Purpose 16: * ======= 17: * 18: * DPTSV computes the solution to a real system of linear equations 19: * A*X = B, where A is an N-by-N symmetric positive definite tridiagonal 20: * matrix, and X and B are N-by-NRHS matrices. 21: * 22: * A is factored as A = L*D*L**T, and the factored form of A is then 23: * used to solve the system of equations. 24: * 25: * Arguments 26: * ========= 27: * 28: * N (input) INTEGER 29: * The order of the matrix A. N >= 0. 30: * 31: * NRHS (input) INTEGER 32: * The number of right hand sides, i.e., the number of columns 33: * of the matrix B. NRHS >= 0. 34: * 35: * D (input/output) DOUBLE PRECISION array, dimension (N) 36: * On entry, the n diagonal elements of the tridiagonal matrix 37: * A. On exit, the n diagonal elements of the diagonal matrix 38: * D from the factorization A = L*D*L**T. 39: * 40: * E (input/output) DOUBLE PRECISION array, dimension (N-1) 41: * On entry, the (n-1) subdiagonal elements of the tridiagonal 42: * matrix A. On exit, the (n-1) subdiagonal elements of the 43: * unit bidiagonal factor L from the L*D*L**T factorization of 44: * A. (E can also be regarded as the superdiagonal of the unit 45: * bidiagonal factor U from the U**T*D*U factorization of A.) 46: * 47: * B (input/output) DOUBLE PRECISION array, dimension (LDB,NRHS) 48: * On entry, the N-by-NRHS right hand side matrix B. 49: * On exit, if INFO = 0, the N-by-NRHS solution matrix X. 50: * 51: * LDB (input) INTEGER 52: * The leading dimension of the array B. LDB >= max(1,N). 53: * 54: * INFO (output) INTEGER 55: * = 0: successful exit 56: * < 0: if INFO = -i, the i-th argument had an illegal value 57: * > 0: if INFO = i, the leading minor of order i is not 58: * positive definite, and the solution has not been 59: * computed. The factorization has not been completed 60: * unless i = N. 61: * 62: * ===================================================================== 63: * 64: * .. External Subroutines .. 65: EXTERNAL DPTTRF, DPTTRS, XERBLA 66: * .. 67: * .. Intrinsic Functions .. 68: INTRINSIC MAX 69: * .. 70: * .. Executable Statements .. 71: * 72: * Test the input parameters. 73: * 74: INFO = 0 75: IF( N.LT.0 ) THEN 76: INFO = -1 77: ELSE IF( NRHS.LT.0 ) THEN 78: INFO = -2 79: ELSE IF( LDB.LT.MAX( 1, N ) ) THEN 80: INFO = -6 81: END IF 82: IF( INFO.NE.0 ) THEN 83: CALL XERBLA( 'DPTSV ', -INFO ) 84: RETURN 85: END IF 86: * 87: * Compute the L*D*L' (or U'*D*U) factorization of A. 88: * 89: CALL DPTTRF( N, D, E, INFO ) 90: IF( INFO.EQ.0 ) THEN 91: * 92: * Solve the system A*X = B, overwriting B with X. 93: * 94: CALL DPTTRS( N, NRHS, D, E, B, LDB, INFO ) 95: END IF 96: RETURN 97: * 98: * End of DPTSV 99: * 100: END