PDA_RINP[x] - Reorder an array in place using a permutation index

Description:

This routine reorders an array (in place) using an permutation vector. This is most likely the output from one of the sorting routines PDA_QSI[A|D][x]

Invocation:

CALL PDA_RINP[x]( PERM, N, X, IFAIL )

Arguments:

PERM( N ) = INTEGER (Given and Returned)

The index vector. Note this is modified but should be returned in the same state as when input. Indices may not be negative.

N = INTEGER (Given)

Number of elements.

X( N ) = ? (Given and Returned)

The array to reorder.

IFAIL = INTEGER (Returned)

Status flag. Set 0 for success, otherwise the permutation isn't correct.

Notes:

• Re-ordering is trivial if two arrays are available.

  DO I = 1, N XX( I ) = X( PERM( I ) ) END DO

  The XX array contains the sorted values on completion.

• There is a routine for each of the data types integer, real and double precision; replace [x] in the routine name by I, R or D as appropriate. The data type of the X argument should match the routine being used.

Timing

Proportional to N.