New commands created in association with modified arrayed mode, May 2002

These are non-2-letter commands that give the user control over data sorting and allow viewing of data quadrants not normally displayed.  None of these commands is necessary for correct processing of data, but may be useful in some situations.

Hypercomplex, echo-antiecho and States-TPPI experiments all acquire 2 FIDs for each t₁ value, and hence are referred to here as "pairwise" data.   A new command, array 2 (also referred to as "Pairwise Complex Arrayed Mode") was created to work with data so as to preserve all data quadrants during processing, which is necessary to allow phasing in both dimensions after processing.

For the purposes of the following descriptions, a notation has been devised.  The first FID of each pair is labeled as the A data set, the second is labeled as the B data set.  Each has both real and imaginary halves, referred to as A.r, A.i, B.r and B.i.  (The conventional notation of RR, IR, RI and II can become confusing when considering operations such as the pairwise adding and subtracting done when processing echo-antiecho data, and this notation seems easier to follow.)

When the Processing Type (PT) is set to 2D_Hypercomplex, 2D_EchoAntiecho or 2D_StatesTPPI, when arrayed mode is entered (AR command), NUTS actually enters the array 2 mode.  Data is sorted such that odd-numbered slices become A and even-numbered slices become B.  Only the real half of the A data set is displayed (A.r).

Note that this means that, in Pairwise Complex arrayed mode, NUTS counts the data size in the indirect dimension (number of FIDs) as complex points, and not as total number of slices, as it has previously done. 

The RI command can be used to swap the real and imaginary halves of the data, allowing A.i to be displayed. 

To view the B half of the data, it must first be swapped with the A half, as only the A half can be displayed.  A new command called AB has been created.  AB takes 2 arguments which are the labels of the 2 quadrants to be swapped.  The labels are ar, ai, br and bi, corresponding to A.r, A.i, B.r and B.i, respectively.    For example, to display the B.r data, type

ab arbr <enter>     (note no space between ar and br)

It is important to keep track of what you've moved where!

The TD command (Transpose Data) can take one of 3 arguments to specify how the quadrants are sorted during the transpose.  If the Processing Type has been set correctly, the argument is not needed;  TD without any argument will execute the appropriate sorting.

TD hyper - for hypercomplex and States-TPPI data.  This swaps A.i and B.r during the transpose.

TD echo - for echo-antiecho data.  This swaps A.i and B.i during the transpose.

TD noswap - does no swapping, just transposes each quadrant separately.

Extension of the new arrayed mode to handle TPPI data was done in Nov, 2002.  See instructions for processing.

TPPI data is phase-sensitive, but it is not "pairwise" data - only one FID is acquired per t₁ value - so we don't want to split the data into A and B halves.  The FIDs comprise the A half of the data, and we want all zeroes in the B half.   Nuts has been modified to do this with the command

ar tppi2pairwise

This fills out the B half of the data with zeroes, enters the pairwise arrayed mode, and sets process type to 2D_TPPI.

Process as usual (window fcn, FT, phase, BC).  The transpose needs to be done without data sorting, which is handled automatically, based on the PT setting.

Process in the indirect dimension as usual for TPPI data (using Real FT !!).  

Last updated:  12/4/02