Section 3: library functions
NAME dlamch.f – SYNOPSIS Functions/Subroutines DOUBLE PRECISION function dlamch (CMACH) DLAMCH DOUBLE PRECISION function dlamc3 (A, B) DLAMC3 Function/Subroutine Documentation DOUBLE PRECISION function dlamc3 (double precisionA, double precisionB) DLAMC3 Purpose: DLAMC3 is intended to force A and B to be stored prior to doing the addition of A and B , for use in situations…
NAME dlamchf77.f – SYNOPSIS Functions/Subroutines DOUBLE PRECISION function dlamch (CMACH) DLAMCHF77 deprecated subroutine dlamc1 (BETA, T, RND, IEEE1) DLAMC1 subroutine dlamc2 (BETA, T, RND, EPS, EMIN, RMIN, EMAX, RMAX) DLAMC2 DOUBLE PRECISION function dlamc3 (A, B) DLAMC3 subroutine dlamc4 (EMIN, START, BASE) DLAMC4 subroutine dlamc5 (BETA, P, EMIN, IEEE, EMAX, RMAX) DLAMC5 Function/Subroutine Documentation subroutine…
NAME dlamchf77.f – SYNOPSIS Functions/Subroutines DOUBLE PRECISION function dlamch (CMACH) DLAMCHF77 deprecated subroutine dlamc1 (BETA, T, RND, IEEE1) DLAMC1 subroutine dlamc2 (BETA, T, RND, EPS, EMIN, RMIN, EMAX, RMAX) DLAMC2 DOUBLE PRECISION function dlamc3 (A, B) DLAMC3 subroutine dlamc4 (EMIN, START, BASE) DLAMC4 subroutine dlamc5 (BETA, P, EMIN, IEEE, EMAX, RMAX) DLAMC5 Function/Subroutine Documentation subroutine…
NAME dlalsd.f – SYNOPSIS Functions/Subroutines subroutine dlalsd (UPLO, SMLSIZ, N, NRHS, D, E, B, LDB, RCOND, RANK, WORK, IWORK, INFO) DLALSD uses the singular value decomposition of A to solve the least squares problem. Function/Subroutine Documentation subroutine dlalsd (characterUPLO, integerSMLSIZ, integerN, integerNRHS, double precision, dimension( * )D, double precision, dimension( * )E, double precision, dimension(…
NAME dlalsa.f – SYNOPSIS Functions/Subroutines subroutine dlalsa (ICOMPQ, SMLSIZ, N, NRHS, B, LDB, BX, LDBX, U, LDU, VT, K, DIFL, DIFR, Z, POLES, GIVPTR, GIVCOL, LDGCOL, PERM, GIVNUM, C, S, WORK, IWORK, INFO) DLALSA computes the SVD of the coefficient matrix in compact form. Used by sgelsd. Function/Subroutine Documentation subroutine dlalsa (integerICOMPQ, integerSMLSIZ, integerN, integerNRHS,…
NAME dlals0.f – SYNOPSIS Functions/Subroutines subroutine dlals0 (ICOMPQ, NL, NR, SQRE, NRHS, B, LDB, BX, LDBX, PERM, GIVPTR, GIVCOL, LDGCOL, GIVNUM, LDGNUM, POLES, DIFL, DIFR, Z, K, C, S, WORK, INFO) DLALS0 applies back multiplying factors in solving the least squares problem using divide and conquer SVD approach. Used by sgelsd. Function/Subroutine Documentation subroutine dlals0…
NAME dlaln2.f – SYNOPSIS Functions/Subroutines subroutine dlaln2 (LTRANS, NA, NW, SMIN, CA, A, LDA, D1, D2, B, LDB, WR, WI, X, LDX, SCALE, XNORM, INFO) DLALN2 solves a 1-by-1 or 2-by-2 linear system of equations of the specified form. Function/Subroutine Documentation subroutine dlaln2 (logicalLTRANS, integerNA, integerNW, double precisionSMIN, double precisionCA, double precision, dimension( lda, *…
NAME dlaisnan.f – SYNOPSIS Functions/Subroutines LOGICAL function dlaisnan (DIN1, DIN2) DLAISNAN tests input for NaN by comparing two arguments for inequality. Function/Subroutine Documentation LOGICAL function dlaisnan (double precisionDIN1, double precisionDIN2) DLAISNAN tests input for NaN by comparing two arguments for inequality. Purpose: This routine is not for general use. It exists solely to avoid over-optimization…
NAME dlaic1.f – SYNOPSIS Functions/Subroutines subroutine dlaic1 (JOB, J, X, SEST, W, GAMMA, SESTPR, S, C) DLAIC1 applies one step of incremental condition estimation. Function/Subroutine Documentation subroutine dlaic1 (integerJOB, integerJ, double precision, dimension( j )X, double precisionSEST, double precision, dimension( j )W, double precisionGAMMA, double precisionSESTPR, double precisionS, double precisionC) DLAIC1 applies one step of…
NAME dlahrd.f – SYNOPSIS Functions/Subroutines subroutine dlahrd (N, K, NB, A, LDA, TAU, T, LDT, Y, LDY) DLAHRD reduces the first nb columns of a general rectangular matrix A so that elements below the k-th subdiagonal are zero, and returns auxiliary matrices which are needed to apply the transformation to the unreduced part of A….
NAME dlahr2.f – SYNOPSIS Functions/Subroutines subroutine dlahr2 (N, K, NB, A, LDA, TAU, T, LDT, Y, LDY) DLAHR2 reduces the specified number of first columns of a general rectangular matrix A so that elements below the specified subdiagonal are zero, and returns auxiliary matrices which are needed to apply the transformation to the unreduced part…
NAME dlahqr.f – SYNOPSIS Functions/Subroutines subroutine dlahqr (WANTT, WANTZ, N, ILO, IHI, H, LDH, WR, WI, ILOZ, IHIZ, Z, LDZ, INFO) DLAHQR computes the eigenvalues and Schur factorization of an upper Hessenberg matrix, using the double-shift/single-shift QR algorithm. Function/Subroutine Documentation subroutine dlahqr (logicalWANTT, logicalWANTZ, integerN, integerILO, integerIHI, double precision, dimension( ldh, * )H, integerLDH, double…
NAME dlagv2.f – SYNOPSIS Functions/Subroutines subroutine dlagv2 (A, LDA, B, LDB, ALPHAR, ALPHAI, BETA, CSL, SNL, CSR, SNR) DLAGV2 computes the Generalized Schur factorization of a real 2-by-2 matrix pencil (A,B) where B is upper triangular. Function/Subroutine Documentation subroutine dlagv2 (double precision, dimension( lda, * )A, integerLDA, double precision, dimension( ldb, * )B, integerLDB, double…
NAME dlagts.f – SYNOPSIS Functions/Subroutines subroutine dlagts (JOB, N, A, B, C, D, IN, Y, TOL, INFO) DLAGTS solves the system of equations (T-λI)x = y or (T-λI)Tx = y,where T is a general tridiagonal matrix and λ a scalar, using the LU factorization computed by slagtf. Function/Subroutine Documentation subroutine dlagts (integerJOB, integerN, double precision,…
NAME dlagtm.f – SYNOPSIS Functions/Subroutines subroutine dlagtm (TRANS, N, NRHS, ALPHA, DL, D, DU, X, LDX, BETA, B, LDB) DLAGTM performs a matrix-matrix product of the form C = αAB+βC, where A is a tridiagonal matrix, B and C are rectangular matrices, and α and β are scalars, which may be 0, 1, or -1….
NAME dlagtf.f – SYNOPSIS Functions/Subroutines subroutine dlagtf (N, A, LAMBDA, B, C, TOL, D, IN, INFO) DLAGTF computes an LU factorization of a matrix T-λI, where T is a general tridiagonal matrix, and λ a scalar, using partial pivoting with row interchanges. Function/Subroutine Documentation subroutine dlagtf (integerN, double precision, dimension( * )A, double precisionLAMBDA, double…
NAME dlags2.f – SYNOPSIS Functions/Subroutines subroutine dlags2 (UPPER, A1, A2, A3, B1, B2, B3, CSU, SNU, CSV, SNV, CSQ, SNQ) DLAGS2 computes 2-by-2 orthogonal matrices U, V, and Q, and applies them to matrices A and B such that the rows of the transformed A and B are parallel. Function/Subroutine Documentation subroutine dlags2 (logicalUPPER, double…
NAME dlag2s.f – SYNOPSIS Functions/Subroutines subroutine dlag2s (M, N, A, LDA, SA, LDSA, INFO) DLAG2S converts a double precision matrix to a single precision matrix. Function/Subroutine Documentation subroutine dlag2s (integerM, integerN, double precision, dimension( lda, * )A, integerLDA, real, dimension( ldsa, * )SA, integerLDSA, integerINFO) DLAG2S converts a double precision matrix to a single precision…
NAME dlag2.f – SYNOPSIS Functions/Subroutines subroutine dlag2 (A, LDA, B, LDB, SAFMIN, SCALE1, SCALE2, WR1, WR2, WI) DLAG2 computes the eigenvalues of a 2-by-2 generalized eigenvalue problem, with scaling as necessary to avoid over-/underflow. Function/Subroutine Documentation subroutine dlag2 (double precision, dimension( lda, * )A, integerLDA, double precision, dimension( ldb, * )B, integerLDB, double precisionSAFMIN, double…
NAME dlaexc.f – SYNOPSIS Functions/Subroutines subroutine dlaexc (WANTQ, N, T, LDT, Q, LDQ, J1, N1, N2, WORK, INFO) DLAEXC swaps adjacent diagonal blocks of a real upper quasi-triangular matrix in Schur canonical form, by an orthogonal similarity transformation. Function/Subroutine Documentation subroutine dlaexc (logicalWANTQ, integerN, double precision, dimension( ldt, * )T, integerLDT, double precision, dimension( ldq,…