The "Generate Guess File" Tab allows you generate a fitMANSuite compatible guess file from a PINTS Simulation Experiment. See here for more details about how a guess file is structured.

Before you use this tab, ensure you have loaded an experiment, properly specified the amplitudes and T₂ values, and defined, saved, and applied your constraints.

The "Generate Guess File" Tab is organized as follows:

• On the left-hand side, there are three panels:

  • The first panel allows you to load in an acquired fitMANSuite *.dat file
  • The second panel allows you modify global guess file parameters and to plot the guess file to visualize what it looks like.
  • The third panel allows the user to generate and save the guess file.

  

• On the right-hand side, there is one panel where the preliminary guess and the acquired data are plotted.

Load a *.dat file by hitting the Browse button and selecting a file. Hit the confirm button to load the file into the application.

There are 5 guess file parameters that you can add. These correspond to variables that will listed in the [Variables] section of the generated guess file.

Parameter	Corresponding Variable	Effect
Shift Factor (ppm)	sfactor	Shifts all peaks along the frequency axis.
Amplitude Factor	afactor	Scales all peaks by the amplitude factor.
Delay Factor (sec)	dfactor	Applies a first-order phase to the entire spectrum.
Width Factor (Hz)	wfactor	Applies an exponential filter to the entire spectrum.
Phase Factor (rad)	pfactor	Applies a zero-order phase to the entire spectrum.

You can modify these parameters, hit the Plot button, and visualize how that changes the overall "guess" relative to the acquired data.

Remember, the "guess" is the initialization for the minimization algorithm. Overall, prior to fitting, we must ensure that the initial parameter value estimates for all metabolites creates a model that is "close" to the acquired data (see here for more details). Editing the guess file parameters in this panel will bring you one step closer to good initial parameter values.

Note that these guess file parameters are global variables that affect the entire spectrum. Parameter values for each metabolite may be more finely adjusted by editing the guess file directly and visualizing it in the fitMANSuite.

Specify where you want to save the guess file in the Output Filename field. Confirm the location by hitting the Confirm button and write the file by hitting the Generate .ges file button.