Modal Analysis Options
Minimum Total- Unknown compositions that sum below this value will not be used in the point count analysis. A default minimum sum of 90% or 95% is suggested. Increase the minimum total value to reject points that sum lower.
Normalize Concentrations For Fit- This option is used to specify if the standard and unknown concentrations should be normalized to 100% before the vector fit is calculated. Of course, this applies only to those concentrations that have already met the Minimum Total tolerance.
Weight Concentrations For Fit- This option is used to specify if the element concentrations for the standards that define each phase should be weighted based on the average composition of the element in that phase. If the major elements in a phase should have a greater influence in determining the vector fit, then this option should be selected. If all concentrations, regardless of magnitude should have equal weight in the vector fit, this option should not be selected.
Minimum Vector- The tolerance for the match to a defined phase. A default value of 4.0 is suggested. If a closer match is desired for one or more phases in the group, decrease the vector value for that phase. The vector is calculated by simply taking the square root of the sums of the differences squared to each n-dimensional phase. Note that all weight percents, for both standards and unknowns, are normalized to 100% prior to the vector fit. The calculation is shown below for a one dimensional phase :
Where 
and 
are the
components (elements) to be compared
Mineral end-member- A mineral end-member calculation for one of the following phases, Feldspar, Olivine, Pyroxene and Garnet may also be specified.