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 Generated automatically by Doxygen for LAPACK from the source code. LAPACK Version 3.12.0 TESTING/LIN/sptt02.f(3)