- type: Setup command.
- function: The command defines the randomization parameters for
the bunch pattern. The randomization is performed on the ideal bunch
pattern before each growth rate calculation. If a sweep of frequency
is requested (
`sweepFrequency`), then a new random bunch pattern is generated for each HOM frequency value. If a HOM-frequency Monte Carlo simulation is requested (`randomizeHOMFrequencies`), then a new random bunch pattern is generated for each HOM frequency sample. Thus there are two random components in the resulting growth rate distribution: HOM frequency and bunch population.

&randomizeBunchCurrent struct long seed = -987654323; long uniform = 1; double absoluteSpreadMA = 0; double relativeSpread = 0; &end.

`seed`-- A large negative number for the random number generator. This will use an independent generator from the HOM frequency.`uniform`-- Flag for uniform distribution. Presently only uniform distribution is available.`absoluteSpreadMA`-- Spread in bunch distribution in units of mA. This is useful in top-up mode injection where the total current is constant but individual bunches have spread equal to the charge per injection bunch. For example if a bunch pattern has 4 mA per bunch and the spread is 1 mA, then some bunches may have current as low as 3.5 mA and others as high as 4.5 mA.`relativeSpread`-- Spread in bunch distribution in fraction.

subsectionsweepFrequency

- type: Setup command
- function: Sets up a sweep of the resonator frequency value of a selected HOM. The setup takes effect only when an action command is executed.

&sweepHOMFrequency long resonatorNumber = 0 double frequencyRange = 0.0 long points = 100 STRING filename = NULL &end

`resonatorNumber`-- HOM resonator number to be swept in frequency. The numbering starts at 0, and proceed in the order that the resonators were read in the HOM definition file or files.`frequencyRange`-- Sweep range in Hz. The range starts at the unperturbed HOM resonator frequency minus`frequencyRangeHz`and ends at the unperturbed HOM resonator frequency plus`frequencyRangeHz`. If`frequencyRangeHz`is set to 0 or not specified, then`frequencyRangeHz`= where is the revolution frequency.`points`-- Number of points in the sweep.`filename`--`SDDS`file in which the results are written. The columns are the swept HOM frequency, the maximum growth rate, and the frequency shift of the fastest growing CBM. Recommended naming conventions:`<something>.CBMFreq`