Section 3: library functions
dlags2.f – SynopsisFunctions/Subroutinessubroutine 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 Documentationsubroutine dlags2 (logicalUPPER, double precisionA1, double precisionA2, double…
dlag2s.f – SynopsisFunctions/Subroutinessubroutine dlag2s (M, N, A, LDA, SA, LDSA, INFO) DLAG2S converts a double precision matrix to a single precision matrix. Function/Subroutine Documentationsubroutine 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 matrix. Purpose: DLAG2S converts a…
dlag2.f – SynopsisFunctions/Subroutinessubroutine 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 Documentationsubroutine dlag2 (double precision, dimension( lda, * )A, integerLDA, double precision, dimension( ldb, * )B, integerLDB, double precisionSAFMIN, double precisionSCALE1, double precisionSCALE2, double…
dlaexc.f – SynopsisFunctions/Subroutinessubroutine 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 Documentationsubroutine dlaexc (logicalWANTQ, integerN, double precision, dimension( ldt, * )T, integerLDT, double precision, dimension( ldq, * )Q, integerLDQ, integerJ1,…
dlaev2.f – SynopsisFunctions/Subroutinessubroutine dlaev2 (A, B, C, RT1, RT2, CS1, SN1) DLAEV2 computes the eigenvalues and eigenvectors of a 2-by-2 symmetric/Hermitian matrix. Function/Subroutine Documentationsubroutine dlaev2 (double precisionA, double precisionB, double precisionC, double precisionRT1, double precisionRT2, double precisionCS1, double precisionSN1)DLAEV2 computes the eigenvalues and eigenvectors of a 2-by-2 symmetric/Hermitian matrix. Purpose: DLAEV2 computes the eigendecomposition of…
dlaein.f – SynopsisFunctions/Subroutinessubroutine dlaein (RIGHTV, NOINIT, N, H, LDH, WR, WI, VR, VI, B, LDB, WORK, EPS3, SMLNUM, BIGNUM, INFO) DLAEIN computes a specified right or left eigenvector of an upper Hessenberg matrix by inverse iteration. Function/Subroutine Documentationsubroutine dlaein (logicalRIGHTV, logicalNOINIT, integerN, double precision, dimension( ldh, * )H, integerLDH, double precisionWR, double precisionWI, double precision,…
dlaeda.f – SynopsisFunctions/Subroutinessubroutine dlaeda (N, TLVLS, CURLVL, CURPBM, PRMPTR, PERM, GIVPTR, GIVCOL, GIVNUM, Q, QPTR, Z, ZTEMP, INFO) DLAEDA used by sstedc. Computes the Z vector determining the rank-one modification of the diagonal matrix. Used when the original matrix is dense. Function/Subroutine Documentationsubroutine dlaeda (integerN, integerTLVLS, integerCURLVL, integerCURPBM, integer, dimension( * )PRMPTR, integer, dimension( *…
dlaed9.f – SynopsisFunctions/Subroutinessubroutine dlaed9 (K, KSTART, KSTOP, N, D, Q, LDQ, RHO, DLAMDA, W, S, LDS, INFO) DLAED9 used by sstedc. Finds the roots of the secular equation and updates the eigenvectors. Used when the original matrix is dense. Function/Subroutine Documentationsubroutine dlaed9 (integerK, integerKSTART, integerKSTOP, integerN, double precision, dimension( * )D, double precision, dimension( ldq,…
dlaed8.f – SynopsisFunctions/Subroutinessubroutine dlaed8 (ICOMPQ, K, N, QSIZ, D, Q, LDQ, INDXQ, RHO, CUTPNT, Z, DLAMDA, Q2, LDQ2, W, PERM, GIVPTR, GIVCOL, GIVNUM, INDXP, INDX, INFO) DLAED8 used by sstedc. Merges eigenvalues and deflates secular equation. Used when the original matrix is dense. Function/Subroutine Documentationsubroutine dlaed8 (integerICOMPQ, integerK, integerN, integerQSIZ, double precision, dimension( * )D,…
dlaed7.f – SynopsisFunctions/Subroutinessubroutine dlaed7 (ICOMPQ, N, QSIZ, TLVLS, CURLVL, CURPBM, D, Q, LDQ, INDXQ, RHO, CUTPNT, QSTORE, QPTR, PRMPTR, PERM, GIVPTR, GIVCOL, GIVNUM, WORK, IWORK, INFO) DLAED7 used by sstedc. Computes the updated eigensystem of a diagonal matrix after modification by a rank-one symmetric matrix. Used when the original matrix is dense. Function/Subroutine Documentationsubroutine dlaed7…
dlaed6.f – SynopsisFunctions/Subroutinessubroutine dlaed6 (KNITER, ORGATI, RHO, D, Z, FINIT, TAU, INFO) DLAED6 used by sstedc. Computes one Newton step in solution of the secular equation. Function/Subroutine Documentationsubroutine dlaed6 (integerKNITER, logicalORGATI, double precisionRHO, double precision, dimension( 3 )D, double precision, dimension( 3 )Z, double precisionFINIT, double precisionTAU, integerINFO)DLAED6 used by sstedc. Computes one Newton step…
dlaed5.f – SynopsisFunctions/Subroutinessubroutine dlaed5 (I, D, Z, DELTA, RHO, DLAM) DLAED5 used by sstedc. Solves the 2-by-2 secular equation. Function/Subroutine Documentationsubroutine dlaed5 (integerI, double precision, dimension( 2 )D, double precision, dimension( 2 )Z, double precision, dimension( 2 )DELTA, double precisionRHO, double precisionDLAM)DLAED5 used by sstedc. Solves the 2-by-2 secular equation. Purpose: This subroutine computes the…
dlaed4.f – SynopsisFunctions/Subroutinessubroutine dlaed4 (N, I, D, Z, DELTA, RHO, DLAM, INFO) DLAED4 used by sstedc. Finds a single root of the secular equation. Function/Subroutine Documentationsubroutine dlaed4 (integerN, integerI, double precision, dimension( * )D, double precision, dimension( * )Z, double precision, dimension( * )DELTA, double precisionRHO, double precisionDLAM, integerINFO)DLAED4 used by sstedc. Finds a single…
dlaed3.f – SynopsisFunctions/Subroutinessubroutine dlaed3 (K, N, N1, D, Q, LDQ, RHO, DLAMDA, Q2, INDX, CTOT, W, S, INFO) DLAED3 used by sstedc. Finds the roots of the secular equation and updates the eigenvectors. Used when the original matrix is tridiagonal. Function/Subroutine Documentationsubroutine dlaed3 (integerK, integerN, integerN1, double precision, dimension( * )D, double precision, dimension( ldq,…
dlaed2.f – SynopsisFunctions/Subroutinessubroutine dlaed2 (K, N, N1, D, Q, LDQ, INDXQ, RHO, Z, DLAMDA, W, Q2, INDX, INDXC, INDXP, COLTYP, INFO) DLAED2 used by sstedc. Merges eigenvalues and deflates secular equation. Used when the original matrix is tridiagonal. Function/Subroutine Documentationsubroutine dlaed2 (integerK, integerN, integerN1, double precision, dimension( * )D, double precision, dimension( ldq, * )Q,…
dlaed1.f – SynopsisFunctions/Subroutinessubroutine dlaed1 (N, D, Q, LDQ, INDXQ, RHO, CUTPNT, WORK, IWORK, INFO) DLAED1 used by sstedc. Computes the updated eigensystem of a diagonal matrix after modification by a rank-one symmetric matrix. Used when the original matrix is tridiagonal. Function/Subroutine Documentationsubroutine dlaed1 (integerN, double precision, dimension( * )D, double precision, dimension( ldq, * )Q,…
dlaed0.f – SynopsisFunctions/Subroutinessubroutine dlaed0 (ICOMPQ, QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, WORK, IWORK, INFO) DLAED0 used by sstedc. Computes all eigenvalues and corresponding eigenvectors of an unreduced symmetric tridiagonal matrix using the divide and conquer method. Function/Subroutine Documentationsubroutine dlaed0 (integerICOMPQ, integerQSIZ, integerN, double precision, dimension( * )D, double precision, dimension( * )E, double…
dlaebz.f – SynopsisFunctions/Subroutinessubroutine dlaebz (IJOB, NITMAX, N, MMAX, MINP, NBMIN, ABSTOL, RELTOL, PIVMIN, D, E, E2, NVAL, AB, C, MOUT, NAB, WORK, IWORK, INFO) DLAEBZ computes the number of eigenvalues of a real symmetric tridiagonal matrix which are less than or equal to a given value, and performs other tasks required by the routine sstebz….
dlae2.f – SynopsisFunctions/Subroutinessubroutine dlae2 (A, B, C, RT1, RT2) DLAE2 computes the eigenvalues of a 2-by-2 symmetric matrix. Function/Subroutine Documentationsubroutine dlae2 (double precisionA, double precisionB, double precisionC, double precisionRT1, double precisionRT2)DLAE2 computes the eigenvalues of a 2-by-2 symmetric matrix. Purpose: DLAE2 computes the eigenvalues of a 2-by-2 symmetric matrix [ A B ] [ B…
dladiv.f – SynopsisFunctions/Subroutinessubroutine dladiv (A, B, C, D, P, Q) DLADIV performs complex division in real arithmetic, avoiding unnecessary overflow. subroutine dladiv1 (A, B, C, D, P, Q) DOUBLE PRECISION function dladiv2 (A, B, C, D, R, T) Function/Subroutine Documentationsubroutine dladiv (double precisionA, double precisionB, double precisionC, double precisionD, double precisionP, double precisionQ)DLADIV performs complex…