# slasq4.f(3) [centos man page]

slasq4.f(3) LAPACK slasq4.f(3)NAME

slasq4.f-SYNOPSIS

Functions/Subroutines subroutine slasq4 (I0, N0, Z, PP, N0IN, DMIN, DMIN1, DMIN2, DN, DN1, DN2, TAU, TTYPE, G) SLASQ4 computes an approximation to the smallest eigenvalue using values of d from the previous transform. Used by sbdsqr.Function/Subroutine Documentation subroutine slasq4 (integerI0, integerN0, real, dimension( * )Z, integerPP, integerN0IN, realDMIN, realDMIN1, realDMIN2, realDN, realDN1, realDN2, realTAU, integerTTYPE, realG) SLASQ4 computes an approximation to the smallest eigenvalue using values of d from the previous transform. Used by sbdsqr. Purpose: SLASQ4 computes an approximation TAU to the smallest eigenvalue using values of d from the previous transform. Parameters: I0 I0 is INTEGER First index. N0 N0 is INTEGER Last index. Z Z is REAL array, dimension ( 4*N ) Z holds the qd array. PP PP is INTEGER PP=0 for ping, PP=1 for pong. N0IN N0IN is INTEGER The value of N0 at start of EIGTEST. DMIN DMIN is REAL Minimum value of d. DMIN1 DMIN1 is REAL Minimum value of d, excluding D( N0 ). DMIN2 DMIN2 is REAL Minimum value of d, excluding D( N0 ) and D( N0-1 ). DN DN is REAL d(N) DN1 DN1 is REAL d(N-1) DN2 DN2 is REAL d(N-2) TAU TAU is REAL This is the shift. TTYPE TTYPE is INTEGER Shift type. G G is REAL G is passed as an argument in order to save its value between calls to SLASQ4. Author: Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. Date: September 2012 Further Details: CNST1 = 9/16 Definition at line 151 of file slasq4.f.AuthorGenerated automatically by Doxygen for LAPACK from the source code.Version 3.4.2Tue Sep 25 2012 slasq4.f(3)

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slasq3.f(3) LAPACK slasq3.f(3)NAME

slasq3.f-SYNOPSIS

Functions/Subroutines subroutine slasq3 (I0, N0, Z, PP, DMIN, SIGMA, DESIG, QMAX, NFAIL, ITER, NDIV, IEEE, TTYPE, DMIN1, DMIN2, DN, DN1, DN2, G, TAU) SLASQ3 checks for deflation, computes a shift and calls dqds. Used by sbdsqr.Function/Subroutine Documentation subroutine slasq3 (integerI0, integerN0, real, dimension( * )Z, integerPP, realDMIN, realSIGMA, realDESIG, realQMAX, integerNFAIL, integerITER, integerNDIV, logicalIEEE, integerTTYPE, realDMIN1, realDMIN2, realDN, realDN1, realDN2, realG, realTAU) SLASQ3 checks for deflation, computes a shift and calls dqds. Used by sbdsqr. Purpose: SLASQ3 checks for deflation, computes a shift (TAU) and calls dqds. In case of failure it changes shifts, and tries again until output is positive. Parameters: I0 I0 is INTEGER First index. N0 N0 is INTEGER Last index. Z Z is REAL array, dimension ( 4*N ) Z holds the qd array. PP PP is INTEGER PP=0 for ping, PP=1 for pong. PP=2 indicates that flipping was applied to the Z array and that the initial tests for deflation should not be performed. DMIN DMIN is REAL Minimum value of d. SIGMA SIGMA is REAL Sum of shifts used in current segment. DESIG DESIG is REAL Lower order part of SIGMA QMAX QMAX is REAL Maximum value of q. NFAIL NFAIL is INTEGER Number of times shift was too big. ITER ITER is INTEGER Number of iterations. NDIV NDIV is INTEGER Number of divisions. IEEE IEEE is LOGICAL Flag for IEEE or non IEEE arithmetic (passed to SLASQ5). TTYPE TTYPE is INTEGER Shift type. DMIN1 DMIN1 is REAL DMIN2 DMIN2 is REAL DN DN is REAL DN1 DN1 is REAL DN2 DN2 is REAL G G is REAL TAU TAU is REAL These are passed as arguments in order to save their values between calls to SLASQ3. Author: Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. Date: September 2012 Definition at line 181 of file slasq3.f.AuthorGenerated automatically by Doxygen for LAPACK from the source code.Version 3.4.2Tue Sep 25 2012 slasq3.f(3)