IDL Reference Guide: Procedures and Functions

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.

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:

Keywords

DOUBLE

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

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