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---
:name: sgbcon
:md5sum: eaa07e1508e7cce0f3ead5f9b4aec35a
:category: :subroutine
:arguments:
- norm:
:type: char
:intent: input
- n:
:type: integer
:intent: input
- kl:
:type: integer
:intent: input
- ku:
:type: integer
:intent: input
- ab:
:type: real
:intent: input
:dims:
- ldab
- n
- ldab:
:type: integer
:intent: input
- ipiv:
:type: integer
:intent: input
:dims:
- n
- anorm:
:type: real
:intent: input
- rcond:
:type: real
:intent: output
- work:
:type: real
:intent: workspace
:dims:
- 3*n
- iwork:
:type: integer
:intent: workspace
:dims:
- n
- info:
:type: integer
:intent: output
:substitutions: {}
:fortran_help: " SUBROUTINE SGBCON( NORM, N, KL, KU, AB, LDAB, IPIV, ANORM, RCOND, WORK, IWORK, INFO )\n\n\
* Purpose\n\
* =======\n\
*\n\
* SGBCON estimates the reciprocal of the condition number of a real\n\
* general band matrix A, in either the 1-norm or the infinity-norm,\n\
* using the LU factorization computed by SGBTRF.\n\
*\n\
* An estimate is obtained for norm(inv(A)), and the reciprocal of the\n\
* condition number is computed as\n\
* RCOND = 1 / ( norm(A) * norm(inv(A)) ).\n\
*\n\n\
* Arguments\n\
* =========\n\
*\n\
* NORM (input) CHARACTER*1\n\
* Specifies whether the 1-norm condition number or the\n\
* infinity-norm condition number is required:\n\
* = '1' or 'O': 1-norm;\n\
* = 'I': Infinity-norm.\n\
*\n\
* N (input) INTEGER\n\
* The order of the matrix A. N >= 0.\n\
*\n\
* KL (input) INTEGER\n\
* The number of subdiagonals within the band of A. KL >= 0.\n\
*\n\
* KU (input) INTEGER\n\
* The number of superdiagonals within the band of A. KU >= 0.\n\
*\n\
* AB (input) REAL array, dimension (LDAB,N)\n\
* Details of the LU factorization of the band matrix A, as\n\
* computed by SGBTRF. U is stored as an upper triangular band\n\
* matrix with KL+KU superdiagonals in rows 1 to KL+KU+1, and\n\
* the multipliers used during the factorization are stored in\n\
* rows KL+KU+2 to 2*KL+KU+1.\n\
*\n\
* LDAB (input) INTEGER\n\
* The leading dimension of the array AB. LDAB >= 2*KL+KU+1.\n\
*\n\
* IPIV (input) INTEGER array, dimension (N)\n\
* The pivot indices; for 1 <= i <= N, row i of the matrix was\n\
* interchanged with row IPIV(i).\n\
*\n\
* ANORM (input) REAL\n\
* If NORM = '1' or 'O', the 1-norm of the original matrix A.\n\
* If NORM = 'I', the infinity-norm of the original matrix A.\n\
*\n\
* RCOND (output) REAL\n\
* The reciprocal of the condition number of the matrix A,\n\
* computed as RCOND = 1/(norm(A) * norm(inv(A))).\n\
*\n\
* WORK (workspace) REAL array, dimension (3*N)\n\
*\n\
* IWORK (workspace) INTEGER array, dimension (N)\n\
*\n\
* INFO (output) INTEGER\n\
* = 0: successful exit\n\
* < 0: if INFO = -i, the i-th argument had an illegal value\n\
*\n\n\
* =====================================================================\n\
*\n"
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