Solver Convergence Monitor - GXMONI

• New style
• Classic style

Solver Convergence Monitor

The Earth solver displays convergence monitoring information in a multi-tabbed window.

The tabs display, as a function of sweep:

• 'CMD' - text output from the solver
• 'Spot value' - the values of all variables at the selected monitor point
• 'Global Maximums' - the largest value in the domain
• 'Global Minimums' - the smallest value in the domain
• 'Residual' - the normalised sum of errors for each variable
• 'Max Correction' - the largest correction between iterations
• 'Net Sources' - the net sum of sources for all variables

Each tab can be displayed by clicking it. Alternatively, the tabs can be pulled out to make individual windows. In this way all six plots can be displayed simultaneously.

Each separate monitor widow can be moved and resized at will. They can be re-docked individually by dragging them back into the main window:

Alternatively, all windows can be re-docked simultaneously by pressing the 'Utilities - Dock all Plots' button.

The ribbon along the top of the window contains the following items, each of which has a 'hover' tooltip:

• Actions
  • Save Results - brings up a dialog for saving a solution file at the current sweep.

    The current sums of net sources are also written to RESULT.

  • Stop Run - will stop the run neatly and save all output files.
  • Abort - stops the run without saving any output files
  • Pause Run - pauses the run until the button is pressed again to continue.
• Runtime Settings
  • Reset Solution Controls - brings up a dialog for resetting various solution control items

    The run remains paused as long as the dialog is displayed. Any changes made are applied when 'OK' is pressed, and the run continues. A note of any changes made is recorded in RESULT.

  • Monitor Probe Location - brings up a dialog for changing the location of the monitor point:

    For parallel cases, the cell numbers entered must refer to the original full domain.

• Utilities
  • Take Screenshot - takes images of each of the monitor plots. The file names will be 'convergence-spot-sweepN.png','convergence-residual-sweepN.png',convergence-domainmin-sweepN.png', 'convergence-domainmax-sweepN.png','convergence-netsources-sweepN.png' and 'domain-maxcorrection-sweepN.png' where N is the sweep (iteration) number.
  • Dock all plots - automatically puts all un-docked plots back into their default positions.
  • Stop MultiRun - creates the file 'stopmulti', needed to prevent a multi-run from proceeding with the next run once the current run finishes.
  • Toggle data tooltip - when the data tooltip toggle is on, hovering the mouse over any convergence plot will display the values at that point:
  • Toggle zooming - when zooming is on, the left or right mouse buttons can be used to pan the image in any of the monitor windows, and the mouse wheel can be used to zoom in and out. Turning zooming off restores the original view.
  • Sliding window width - when a value N>0 is entered into the window width box, the X axes of all the graphs are restricted to only show the last N sweeps on a rolling basis. This can also be switched from Editor, Options, Solver Monitor Options.

Although the new convergence monitor introduces a slightly smaller delay to the solver than the ‘classic’ monitor, it can sometimes struggle to keep up if the screen update time is exceedingly fast. This can happen with very small grids or in transient cases where each step converges in 2-3 sweeps. If this happens, the ‘classic’ monitor may be more advantageous.

Classic Convergence Monitor

The 'classic' solver convergence monitor (the GXMONI screen) can be recovered by adding the line:

SPEDAT(SET, GXMONI, CLASSIC, L, T)

to Group 19 of Q1. If the line is absent, or has 'F' instead of 'T' as the last argument, the new style will be used.

This can also be done from within the VR Editor by selecting 'Classic' on the Options - Monitor options dialog.

Three kinds of monitoring information can be displayed, selected by the setting of ISG50 in Q1 (or in the Editor from Options, Solver Monitor Options or Main Menu, Output, Monitor graph style). The options are:

ISG50 = 0 : display the spot (probe) values on the left, and normalised residuals on the right;

ISG50 = 1 : display maximum value in the field on the left and minimum value on the right; and

ISG50 = 2 : display maximum correction on the left and net sum of sources on the right.

The display can be switched at run-time by interrupting the run and clicking the 'Monitor' box.

By default, the monitor window will start showing 10 sweeps. At 11 sweeps it will rescale to show 100, and at 101 it will rescale to show all sweeps. If the number of sweeps (LSWEEP) is very large, it can be very hard to see the convergence behaviour especially early in the run. The Q1 setting:
SPEDAT(SET,GXMONI,SWEEPWIDTH,I,nsweep)
will cause the monitor window to show the last N sweeps on a rolling basis. This can also be switched from Editor, Options, Solver Monitor Options.

At the end of the Earth Solver run a snapshot of the final convergence monitor screen is saved to the file gxmoni, in the current working directory. This allows the convergence behaviour to be seen at a later time. The snapshot is of whateve monitor display is active at the end of the run.

If all three monitor plots are required, the Q1 setting :
SPEDAT(SET,GXMONI,PLOTALL,L,T)
will cause all three images to be saved as gxmoni_spot, gxmoni_mnmx and gxmoni_mxc. This can also be activated from Editor, Options, Solver Monitor Options.

If these files are not required, their creation can be inhibited by adding to the Q1 file the line:
SPEDAT(SET,GXMONI,TRANSIENT,L,F)

The file type for the gxmoni file is set in CHAM.INI in the [Graphics] section as PlotType. The default setting is gif. The alternative settings are jpg, bmp or pcx.