***PURPOSE Factor a matrix using Gaussian elimination.
***CATEGORY D2A1
***TYPE DOUBLE PRECISION (SGEFA-S, DGEFA-D, CGEFA-C)
***KEYWORDS GENERAL MATRIX, LINEAR ALGEBRA, LINPACK,
MATRIX FACTORIZATION
***AUTHOR Moler, C. B., (U. of New Mexico)
***DESCRIPTION
DGEFA factors a double precision matrix by Gaussian elimination.
DGEFA is usually called by DGECO, but it can be called
directly with a saving in time if RCOND is not needed.
(Time for DGECO) = (1 + 9/N)*(Time for DGEFA) .
On Entry
A DOUBLE PRECISION(LDA, N)
the matrix to be factored.
LDA INTEGER
the leading dimension of the array A .
N INTEGER
the order of the matrix A .
On Return
A an upper triangular matrix and the multipliers
which were used to obtain it.
The factorization can be written A = L*U where
L is a product of permutation and unit lower
triangular matrices and U is upper triangular.
IPVT INTEGER(N)
an integer vector of pivot indices.
INFO INTEGER
= 0 normal value.
= K if U(K,K) .EQ. 0.0 . This is not an error
condition for this subroutine, but it does
indicate that DGESL or DGEDI will divide by zero
if called. Use RCOND in DGECO for a reliable
indication of singularity.
***REFERENCES J. J. Dongarra, J. R. Bunch, C. B. Moler, and G. W.
Stewart, LINPACK Users' Guide, SIAM, 1979.
***ROUTINES CALLED DAXPY, DSCAL, IDAMAX
***REVISION HISTORY (YYMMDD)
780814 DATE WRITTEN
890831 Modified array declarations. (WRB)
890831 REVISION DATE from Version 3.2
891214 Prologue converted to Version 4.0 format. (BAB)
900326 Removed duplicate information from DESCRIPTION section.
(WRB)
920501 Reformatted the REFERENCES section. (WRB)
***END PROLOGUE DGEFA
Namespace: Altaxo.Calc.Ode.Obsolete.DVodeAssembly: AltaxoCore (in AltaxoCore.dll) Version: 4.8.3179.0 (4.8.3179.0)
Syntax public void Run(
ref double[] A,
int offset_a,
int LDA,
int N,
ref int[] IPVT,
int offset_ipvt,
ref int INFO
)
Parameters
- A Double
-
DOUBLE PRECISION(LDA, N)
the matrix to be factored.
- offset_a Int32
[Missing <param name="offset_a"/> documentation for "M:Altaxo.Calc.Ode.Obsolete.DVode.DGEFA.Run(System.Double[]@,System.Int32,System.Int32,System.Int32,System.Int32[]@,System.Int32,System.Int32@)"]
- LDA Int32
-
INTEGER
the leading dimension of the array A .
- N Int32
-
INTEGER
the order of the matrix A .
- IPVT Int32
-
INTEGER(N)
an integer vector of pivot indices.
- offset_ipvt Int32
[Missing <param name="offset_ipvt"/> documentation for "M:Altaxo.Calc.Ode.Obsolete.DVode.DGEFA.Run(System.Double[]@,System.Int32,System.Int32,System.Int32,System.Int32[]@,System.Int32,System.Int32@)"]
- INFO Int32
-
INTEGER
= 0 normal value.
= K if U(K,K) .EQ. 0.0 . This is not an error
condition for this subroutine, but it does
indicate that DGESL or DGEDI will divide by zero
if called. Use RCOND in DGECO for a reliable
indication of singularity.
See Also