From fa080de7afc95aa1c19a6e6fc0e0708ced2eadc4 Mon Sep 17 00:00:00 2001 From: Joseph Hunkeler Date: Wed, 8 Jul 2015 20:46:52 -0400 Subject: Initial commit --- math/slalib/doc/dmat.hlp | 58 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 math/slalib/doc/dmat.hlp (limited to 'math/slalib/doc/dmat.hlp') diff --git a/math/slalib/doc/dmat.hlp b/math/slalib/doc/dmat.hlp new file mode 100644 index 00000000..7d496345 --- /dev/null +++ b/math/slalib/doc/dmat.hlp @@ -0,0 +1,58 @@ +.help dmat Jun99 "Slalib Package" +.nf + + SUBROUTINE slDMAT (N, A, Y, D, JF, IW) + + - - - - - + D M A T + - - - - - + + Matrix inversion & solution of simultaneous equations + (double precision) + + For the set of n simultaneous equations in n unknowns: + A.Y = X + + where: + A is a non-singular N x N matrix + Y is the vector of N unknowns + X is the known vector + + DMATRX computes: + the inverse of matrix A + the determinant of matrix A + the vector of N unknowns + + Arguments: + + symbol type dimension before after + + N i no. of unknowns unchanged + A d (N,N) matrix inverse + Y d (N) vector solution + D d - determinant + * JF i - singularity flag + IW i (N) - workspace + + * JF is the singularity flag. If the matrix is non-singular, + JF=0 is returned. If the matrix is singular, JF=-1 & D=0D0 are + returned. In the latter case, the contents of array A on return + are undefined. + + Algorithm: + Gaussian elimination with partial pivoting. + + Speed: + Very fast. + + Accuracy: + Fairly accurate - errors 1 to 4 times those of routines optimized + for accuracy. + + P.T.Wallace Starlink 7 February 1995 + + Copyright (C) 1995 Rutherford Appleton Laboratory + Copyright (C) 1995 Association of Universities for Research in Astronomy Inc. + +.fi +.endhelp -- cgit