Solves a system of linear equations whose coefficients are in a triangular band matrix.
?tbsvroutines solve one of the following systems of equations:
b, or conjg(
nunit, or non-unit, upper or lower triangular band matrix, with
The routine does not test for singularity or near-singularity.
Such tests must be performed before calling this routine.
- Specifies whether the matrixCHARACTER*1.Ais an upper or lower triangular matrix:ifthe matrix is upper triangular;oruplo='U''u'if, the matrix is low triangular.oruplo='L''l'
- Specifies the system of equations:CHARACTER*1.if, thenortrans= 'N''n';A*x=bif, thenortrans= 'T''t';A'*x=bif, thenortrans= 'C''c'conjg(.A')*x=b
- Specifies whether the matrixCHARACTER*1.Ais unit triangular:ifthen the matrix is unit triangular;ordiag='U''u'if, then the matrix is not unit triangular.ordiag='N''n'
- Specifies the order of the matrixINTEGER.A. The value ofnmust be at least zero.
- On entry withINTEGER.,oruplo='U''u'kspecifies the number of super-diagonals of the matrixA. On entry with,oruplo='L''l'kspecifies the number of sub-diagonals of the matrixA.The value ofkmust satisfy0≤k.
- REALforstbsvDOUBLE PRECISIONfordtbsvCOMPLEXforctbsvDOUBLE COMPLEXforztbsvArray, size(.lda,n)Before entry with, the leadingoruplo='U''u'(byk+ 1)npart of the arrayamust contain the upper triangular band part of the matrix of coefficients, supplied column-by-column,with the leading diagonal of the matrix in rowThe top left(of the array, the first super-diagonal starting at position 2 in rowk+ 1)k, and so on.kbyktriangle of the arrayais not referenced.The following program segment transfers an upper triangular band matrix from conventional full matrix storage (matrix) to band storage (a):do 20, j = 1, n m = k + 1 - j do 10, i = max( 1, j - k ), j a( m + i, j ) = matrix( i, j ) 10 continue 20 continueBefore entry withuplo=