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solve()

Usage:
solve(A [,singok:T] [,quiet:T]), square REAL matrix A
solve(A, B [,singok:T] [,quiet:T]), square REAL matrix A, REAL matrix B,
  with nrows(B) = nrows(A).



Keywords: linear algebra
                                  Usage
solve(a) computes the inverse of the square matrix a.

solve(a,b) computes the solution x to the linear equation a x = b, where
a is square and b is a REAL vector or matrix with the same number of
rows as a.  solve(a,b) is mathematically, but not computationally, the
same as solve(a) %*% b.

For either usage, if a is singular, an informative message is printed
and the operation aborts.

MISSING values are not allowed in a or b.

Expression a %\% b is equivalent to solve(a, b).

                            Keyword 'singok'
solve(a, singok:T) and solve(a, b, singok:T) does the same, except when
a is singular, no message is printed and NULL is returned.  This allows,
for example, a macro to test whether a matrix is singular and take
corrective action.

                             Keyword 'quiet'
Occasionally, "overflow" occurs during the computation.  Any values in
the result that are too large to be represented are replaced by MISSING
and a WARNING message is printed.  You can suppress the message by
including 'quiet:T' as an argument.  If you do, you should use
anymissing() to check the result for the presence of MISSING elements.

                          Propagation of labels
If a has labels, the row and column labels of solve(a) are the column
and row labels of a, respectively.  If b is compatible, the row and
column labels of solve(a,b) are the column labels of a and b
respectively.  If b does not have labels, the column labels of
solve(a,b) are rep("a", ncols(b).  See topic 'labels'.

                            Cross references
See also topics rsolve(), swp(), qr(), 'matrices'.


Gary Oehlert 2006-01-30