IDL

INVERT

INVERT

The INVERT function uses the Gaussian elimination method to compute the inverse of a square array. Errors from singular or near-singular arrays are accumulated in the optional Status argument.

Note: If you are working with complex inputs, use the LA_INVERT function instead.

Examples


; Create an array A:
A = [[ 5.0, -1.0, 3.0], $
   [ 2.0,  0.0, 1.0], $
   [ 3.0,  2.0, 1.0]]
result = INVERT(A)
; We can check the accuracy of the inversion by multiplying the
; inverted array by the original array. The result should be a 3 x
; 3 identity array.
PRINT, result # A

IDL prints:

      1.00000      0.00000      0.00000
      0.00000      1.00000      0.00000
      0.00000  9.53674e-07      1.00000

Syntax


Result = INVERT( Array [, Status] [, /DOUBLE] )

Return Value


The result is a single- or double-precision array of floating or complex values.

Arguments


Array

The array to be inverted. Array must have two dimensions of equal size (i.e., a square array) and can be of any type except string. Note that the resulting array will be composed of single- or double-precision floating-point or complex values, depending on whether the DOUBLE keyword is set.

Status

A named variable to receive the status of the operation. Possible status values are:

  • 0 = Successful completion.
  • 1 = Singular array (which indicates that the inversion is invalid).
  • 2 = Warning that a small pivot element was used and that significant accuracy was probably lost.

Keywords


DOUBLE

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

Version History


Original

Introduced

See Also


COND, DETERM, LA_INVERT, REVERSE, ROTATE, TRANSPOSE

Notes


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