NMRPipe Processing Functions
LS: Left Shift and Zero Pad.
| Flag |
Argument |
Default |
Description |
-ls |
lsPts |
0 |
Left Shift Pnt Count (Valid Units: Pts Hz ppm %). |
-sw |
|
|
Adjust Sweep Width and ppm calibration. |
|
LS applies a left-shift to the points in each vector
from the current dimension of the data. The shifted points at the
start of the data vector are replaced with zeros.
For example, if an 8-point data vector consists of the following
values:
1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0
then after a 2-point left-shift (LS -ls 2) the result
will be:
3.0 4.0 5.0 6.0 7.0 8.0 0.0 0.0
The LS function
will only shift by an integer number of points; for shifting data
by a fractional number of points, use the FSH
function.
OPTIONS
-rs rsVal
Specifies the number of points for the shift. If the number is
positive, the data will be shifted to the right. If it is negative,
the data will be shifted to the left.
This value can also be specified with spectral units (% Hz ppm).
In these cases, the amount of shift requested will be rounded
to the nearest integer.
-sw
If this flag is used with time-domain data, the recorded
time-domain sizes NDAPOD and NDTDSIZE are adjusted by
the number of points shifted. If this flag is used with
frequency-domain data, the chemical shift calibration
information is updated (NDORIG and NDCENTER).
EXAMPLES
The following, when applied in the time-domain, is equivalent
to applying a first order phase of P1=360 in the frequency
domain; applying the zero-fill before the LS avoids losing
one point:
| nmrPipe -fn ZF -auto \
| nmrPipe -fn LS -rs 1 \
SEE ALSO
Shifting functions
RS (right-shift, integer number of points)
CS (circular-shift, integer number of points)
FSH (circular-shift, fractional number of points)
and phase-correction function
PS which can be used to apply the equivalent
of a circular shift in one domain by applying a first order phase
correction in the other domain.
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