PDL::GSL::LINALG(3pm)

1LINALG(3)             User Contributed Perl Documentation            LINALG(3)
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NAME

6       PDL::GSL::LINALG - PDL interface to linear algebra routines in GSL
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SYNOPSIS

9         use PDL::LiteF;
10         use PDL::MatrixOps; # for 'x'
11         use PDL::GSL::LINALG;
12         my $A = pdl [
13           [0.18, 0.60, 0.57, 0.96],
14           [0.41, 0.24, 0.99, 0.58],
15           [0.14, 0.30, 0.97, 0.66],
16           [0.51, 0.13, 0.19, 0.85],
17         ];
18         my $B = sequence(2,4); # column vectors
19         LU_decomp(my $lu=$A->copy, my $p=null, my $signum=null);
20         # transpose so first dim means is vector, higher dims thread
21         LU_solve($lu, $p, $B->transpose, my $x=null);
22         $x = $x->inplace->transpose; # now can be matrix-multiplied
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DESCRIPTION

25       This is an interface to the linear algebra package present in the GNU
26       Scientific Library. Functions are named as in GSL, but with the initial
27       "gsl_linalg_" removed. They are provided in both real and complex
28       double precision.
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30       Currently only LU decomposition interfaces here. Pull requests welcome!
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FUNCTIONS

33   LU_decomp
34         Signature: ([io,phys]A(n,m); indx [o,phys]ipiv(p); int [o,phys]signum())
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36       LU decomposition of the given (real or complex) matrix.
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38       LU_decomp ignores the bad-value flag of the input ndarrays.  It will
39       set the bad-value flag of all output ndarrays if the flag is set for
40       any of the input ndarrays.
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42   LU_solve
43         Signature: ([phys]LU(n,m); indx [phys]ipiv(p); [phys]B(n); [o,phys]x(n))
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45       Solve "A x = B" using the LU and permutation from "LU_decomp", real or
46       complex.
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48       LU_solve ignores the bad-value flag of the input ndarrays.  It will set
49       the bad-value flag of all output ndarrays if the flag is set for any of
50       the input ndarrays.
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52   LU_det
53         Signature: ([phys]LU(n,m); int [phys]signum(); [o]det())
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55       Find the determinant from the LU decomp.
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57       LU_det ignores the bad-value flag of the input ndarrays.  It will set
58       the bad-value flag of all output ndarrays if the flag is set for any of
59       the input ndarrays.
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61   solve_tridiag
62         Signature: ([phys]diag(n); [phys]superdiag(n); [phys]subdiag(n); [phys]B(n); [o,phys]x(n))
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64       Solve "A x = B" where A is a tridiagonal system. Real only, because GSL
65       does not have a complex function.
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67       solve_tridiag ignores the bad-value flag of the input ndarrays.  It
68       will set the bad-value flag of all output ndarrays if the flag is set
69       for any of the input ndarrays.
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NAME

SYNOPSIS

DESCRIPTION

FUNCTIONS

SEE ALSO