TESTING/LIN/sptt02.f(3) | Library Functions Manual | TESTING/LIN/sptt02.f(3) |
NAME
TESTING/LIN/sptt02.f
SYNOPSIS
Functions/Subroutines
subroutine sptt02 (n, nrhs, d, e, x, ldx, b, ldb, resid)
SPTT02
Function/Subroutine Documentation
subroutine sptt02 (integer n, integer nrhs, real, dimension( * ) d, real, dimension( * ) e, real, dimension( ldx, * ) x, integer ldx, real, dimension( ldb, * ) b, integer ldb, real resid)
SPTT02
Purpose:
SPTT02 computes the residual for the solution to a symmetric tridiagonal system of equations: RESID = norm(B - A*X) / (norm(A) * norm(X) * EPS), where EPS is the machine epsilon.
Parameters
N
N is INTEGER The order of the matrix A.
NRHS
NRHS is INTEGER The number of right hand sides, i.e., the number of columns of the matrices B and X. NRHS >= 0.
D
D is REAL array, dimension (N) The n diagonal elements of the tridiagonal matrix A.
E
E is REAL array, dimension (N-1) The (n-1) subdiagonal elements of the tridiagonal matrix A.
X
X is REAL array, dimension (LDX,NRHS) The n by nrhs matrix of solution vectors X.
LDX
LDX is INTEGER The leading dimension of the array X. LDX >= max(1,N).
B
B is REAL array, dimension (LDB,NRHS) On entry, the n by nrhs matrix of right hand side vectors B. On exit, B is overwritten with the difference B - A*X.
LDB
LDB is INTEGER The leading dimension of the array B. LDB >= max(1,N).
RESID
RESID is REAL norm(B - A*X) / (norm(A) * norm(X) * EPS)
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 103 of file sptt02.f.
Author
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