Builtin cost functions

POISE comes with a few, very basic, builtin cost functions. These largely mirror those that are in TopSpin’s native popt screen.

Note

Just like in popt, it is possible to use the dpl command in TopSpin to select a portion of the spectrum to be optimised. This stores the left and right region of the currently active view to the parameters F1P and F2P respectively. This works for all the builtin cost functions except for noe_1d.

More generally, any cost function that uses any of the get1d or get2d functions will respect the bounds placed in F1P and F2P. See Custom cost functions for a more in-depth explanation.

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minabsint

Seeks to minimise the intensity of the magnitude-mode spectrum. The intensity is measured by integration of the entire spectral region, i.e. summation of every point.

Note that this is different from the MAGMIN criterion in popt, which (from what the Bruker documentation suggests) seeks to minimise the highest point in the magnitude-mode spectrum.

maxabsint

Seeks to maximise the intensity of the magnitude-mode spectrum.

minrealint

Seeks to minimise the intensity of the real spectrum (this is probably equivalent to INTMIN in popt).

Note that this does not behave in the same way as minabsint. Because the real spectrum can have negative peaks, this essentially tries to maximise the intensity of negative peaks.

maxrealint

Seeks to maximise the intensity of the real spectrum (equivalent to INTMAX).

zerorealint

Seeks to make the intensity of the real spectrum as close as possible to zero (equivalent to ZERO).

noe_1d

Seeks to minimise the intensity of the spectrum, except for a region of 50 Hz centred on the parameter SPOFFS2 (which corresponds to the frequency of the selective pulse).

Since NOE crosspeaks are typically negative (and apk typically phases them to be so), this essentially seeks to maximise the intensity of the crosspeaks.

Please see the POISE paper for example usage.

epsi_gradient_drift

Performs EPSI processing on a 1D FID, and seeks to minimise the ‘drift’ seen in the echo positions. This is only valid when the echo locations are supposed to be constant, e.g. when there is no indirect-dimension evolution period (otherwise, echoes will be observed at indirect-dimension frequencies). This is to be used for optimising the positive/negative gradient balance in EPSI acquisitions.

Please see the POISE paper for example usage.