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Top Forums UNIX for Advanced & Expert Users How to read a fast written log file at Real time speed? Post 302936629 by achenle on Thursday 26th of February 2015 07:51:49 PM
Old 02-26-2015
That's not really an easy problem to solve. Any solution that meets your requirements has to take into account specifics of the OS, the file system, and even the physical hardware. Obviously such a solution isn't going to be very portable.

The first thing you have to figure out is what's fast enough? Because there's always going to be some delay in reading data from the file after it's been written.

You might be better served interposing something into the logging stream that splits the stream into two - one to the original logging system and one into your real-time parser.
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sptsv.f(3)							      LAPACK								sptsv.f(3)

NAME
sptsv.f - SYNOPSIS
Functions/Subroutines subroutine sptsv (N, NRHS, D, E, B, LDB, INFO) SPTSV computes the solution to system of linear equations A * X = B for PT matrices Function/Subroutine Documentation subroutine sptsv (integerN, integerNRHS, real, dimension( * )D, real, dimension( * )E, real, dimension( ldb, * )B, integerLDB, integerINFO) SPTSV computes the solution to system of linear equations A * X = B for PT matrices Purpose: SPTSV computes the solution to a real system of linear equations A*X = B, where A is an N-by-N symmetric positive definite tridiagonal matrix, and X and B are N-by-NRHS matrices. A is factored as A = L*D*L**T, and the factored form of A is then used to solve the system of equations. Parameters: N N is INTEGER The order of the matrix A. N >= 0. NRHS NRHS is INTEGER The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0. D D is REAL array, dimension (N) On entry, the n diagonal elements of the tridiagonal matrix A. On exit, the n diagonal elements of the diagonal matrix D from the factorization A = L*D*L**T. E E is REAL array, dimension (N-1) On entry, the (n-1) subdiagonal elements of the tridiagonal matrix A. On exit, the (n-1) subdiagonal elements of the unit bidiagonal factor L from the L*D*L**T factorization of A. (E can also be regarded as the superdiagonal of the unit bidiagonal factor U from the U**T*D*U factorization of A.) B B is REAL array, dimension (LDB,NRHS) On entry, the N-by-NRHS right hand side matrix B. On exit, if INFO = 0, the N-by-NRHS solution matrix X. LDB LDB is INTEGER The leading dimension of the array B. LDB >= max(1,N). INFO INFO is INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value > 0: if INFO = i, the leading minor of order i is not positive definite, and the solution has not been computed. The factorization has not been completed unless i = N. Author: Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. Date: September 2012 Definition at line 115 of file sptsv.f. Author Generated automatically by Doxygen for LAPACK from the source code. Version 3.4.2 Tue Sep 25 2012 sptsv.f(3)
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