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NAG[f07vsc] NAG[nag_ztbtrs] - Solution of complex band triangular system of linear equations, multiple right-hand sides
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Calling Sequence
f07vsc(uplo, trans, diag, kd, ab, b, 'n'=n, 'nrhs'=nrhs, 'fail'=fail)
nag_ztbtrs(. . .)
Parameters
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uplo - String;
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On entry: indicates whether  is upper or lower triangular.
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  is upper triangular.
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  is lower triangular.
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Constraint:   "Nag_Upper" or "Nag_Lower". .
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trans - String;
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On entry: indicates the form of the equations
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 The equations are of the form  .
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 The equations are of the form  .
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 The equations are of the form  .
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Constraint:   "Nag_NoTrans", "Nag_Trans" or "Nag_ConjTrans". .
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diag - String;
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On entry: indicates whether  is a non-unit or unit triangular matrix.
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  is a non-unit triangular matrix.
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Constraint:   "Nag_NonUnitDiag" or "Nag_UnitDiag". .
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kd - integer;
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Constraint:  . .
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ab - Matrix(1..dim1, 1..dim2, datatype=complex[8], order=order);
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Note: this array may be supplied in Fortran_order or C_order , as specified by order. All array parameters must use a consistent order.
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b - Matrix(1..dim1, 1..dim2, datatype=complex[8], order=order);
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Note: this array may be supplied in Fortran_order or C_order , as specified by order. All array parameters must use a consistent order.
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'n'=n - integer; (optional)
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Default value: the second dimension of the array ab.
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On entry:  , the order of the matrix  .
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Constraint:  . .
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'nrhs'=nrhs - integer; (optional)
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Default value: the second dimension of the array b.
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On entry:  , the number of right-hand sides.
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Constraint:  . .
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'fail'=fail - table; (optional)
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The NAG error argument, see the documentation for NagError.
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Description
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Purpose
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nag_ztbtrs (f07vsc) solves a complex triangular band system of linear equations with multiple right-hand sides,  ,  or  .
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Description
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nag_ztbtrs (f07vsc) solves a complex triangular band system of linear equations  ,  or  .
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Error Indicators and Warnings
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"NE_ALLOC_FAIL"
Dynamic memory allocation failed.
"NE_BAD_PARAM"
On entry, argument  had an illegal value.
"NE_INT"
On entry,  . Constraint:  .
On entry,  . Constraint:  .
On entry,  . Constraint:  .
"NE_INTERNAL_ERROR"
An internal error has occurred in this function. Check the function call and any array sizes. If the call is correct then please consult NAG for assistance.
"NE_SINGULAR"
The matrix  is singular.
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Further Comments
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The total number of real floating-point operations is approximately  if  .
The real analogue of this function is f07vec (nag_dtbtrs).
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Examples
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uplo := "Nag_Lower":
trans := "Nag_NoTrans":
diag := "Nag_NonUnitDiag":
n := 4:
kd := 2:
nrhs := 2:
ab := Matrix([[0 +0*I , 0 +0*I , -1.94 +4.43*I , 0 +0*I ], [-3.39 +3.44*I , 4.12 -4.27*I , 1.62 +3.68*I , -1.84 +5.53*I ], [0.43 -2.66*I , -2.77 -1.93*I , 1.74 -0.04*I , 0.44 +0.1*I ]], datatype=complex[8], order='C_order'):
b := Matrix([[-8.859999999999999 -3.88*I , -24.09 -5.27*I ], [-15.57 -23.41*I , -57.97 +8.140000000000001*I ], [-7.63 +22.78*I , 19.09 -29.51*I ], [-14.74 -2.4*I , 19.17 +21.33*I ]], datatype=complex[8], order='C_order'):
NAG:-f07vsc(uplo, trans, diag, kd, ab, b, 'n' = n, 'nrhs' = nrhs):
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See Also
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Golub G H and Van Loan C F (1996) Matrix Computations (3rd Edition) Johns Hopkins University Press, Baltimore
Higham N J (1989) The accuracy of solutions to triangular systems SIAM J. Numer. Anal. 26 1252–1265
f07 Chapter Introduction.
NAG Toolbox Overview.
NAG Web Site.
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