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CRAMER

CRAMER

The CRAMER function solves an n by n linear system of equations using Cramer’s rule.

This routine is written in the IDL language. Its source code can be found in the file cramer.pro in the lib subdirectory of the IDL distribution.

Examples


Define an array A and right-hand side vector B.

A = [[ 2.0,  1.0,  1.0], $
     [ 4.0, -6.0, 0.0], $
     [-2.0, 7.0, 2.0]]
B = [3.0, 10.0, -5.0]
;Compute the solution and print.
PRINT, CRAMER(A,B)

IDL prints:

1.00000     -1.00000      2.00000

Syntax


Result = CRAMER( A, B [, /DOUBLE] [, ZERO=value] )

Return Value


Returns the solution of an n by n linear system of equations using Cramer’s rule.

Arguments


A

An n by n single- or double-precision floating-point array.

B

An n-element single- or double-precision floating-point vector.

Keywords


DOUBLE

Set this keyword to force the computation to be done in double-precision arithmetic.

ZERO

Use this keyword to set the value of the floating-point zero. A floating-point zero on the main diagonal of a triangular array results in a zero determinant. A zero determinant results in a “Singular matrix” error and stops the execution of CRAMER. For single-precision inputs, the default value is 1.0 ∞ 10-6. For double-precision inputs, the default value is 1.0 ∞ 10-12.

Version History


Pre 4.0

Introduced

See Also


CHOLSOL, GS_ITER, LU_COMPLEX, LUSOL, SVSOL, TRISOL



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