| comments must be preceeded by the "|" character

        | keywords and values MUST BE ENTERED IN LOWER CASE CHARACTERS!

|---------------------------------------------------------------------

        | the average keyword indicates whether properties of
        | pseudocompounds that represent the same phase are averaged
        | in mode 1 output (they are always averaged in all other 
        | werami computational modes).   

        | this keyword may take values: on, off

average on 

        | this keyword is only relevant for WERAMI
|---------------------------------------------------------------------

        | the composition keyword indicates whether phase 
        | compositions are output in molar or weight proportions.

        | this keyword may take the values: wt, mol

composition mol


        | this keyword is only relevant for WERAMI
|---------------------------------------------------------------------

        | the proportion keyword indicates whether phase 
        | proportions are output as volume, molar or weight 
        | proportions.

        | this keyword may take the values: vol, wt

proportions vol

        | this keyword is only relevant for WERAMI
|---------------------------------------------------------------------
        | the interpolation keyword determines whether werami 
        | does 2-d interpolation/extrapolation for gridded data.

        | CAUTION: interpolation may slow processing dramatically.

        | this keyword is associated with 2 values
        
        | the first value may be: on, off; and controls whether
        | interpolation is attempted

        | the second value is a number that indicates the
        | number of nodes that will be scanned for interpolation
        | points at the lowest grid level. increasing this number 
        | leads to smoother plots, but may also result in erratic 
        | behavior. 

        | interpolation may also result in smoothing of immiscible 
        | phase compositions. 

        | turn interpolation off to view the raw data.

        | see www.perplex.ethz.ch/perplex_werami_options.html

interpolation on  2 

        | this keyword is only relevant for WERAMI
|---------------------------------------------------------------------

        | the extrapolation keyword determines whether werami 
        | does 2-d extrapolation for gridded data when interpolation
        | is not possible. this keyword has no effect if the first
        | value of interpolation is "off"

        | this keyword may take the values: on, off

extrapolation on

        | this keyword is only relevant for WERAMI
|---------------------------------------------------------------------
        | the vrh_weighting keyword determines the weights of the
        | arithemtic mean (value) and harmonic mean (1-value) used 
        | to compute aggregate seismic velocities

        | this keyword may take numeric values: 0->1 

vrh_weighting .5

        | this keyword is only relevant for WERAMI
|---------------------------------------------------------------------
        | the bad_number keyword determines the value asigned to
        | bad numerical results (usually caused by floating point
        | errors). depending on the physical property of interest 
        | it may be useful to change this value so bad results can
        | be distinguished during post-processing (e.g., if seismic
        | velocities are of interest, assigning a negative bad_number
        | allows identification of erroneous velocities).

        | this keyword may take numeric values (< 12 characters) 

bad_number 0.

        | this keyword is only relevant for WERAMI
|---------------------------------------------------------------------

        | the solvus_tolerance keyword specifies the distance (in molar
        | composition space) between coexisting pseudocompounds that is 
        | considered to define distinct phases (i.e., coexisting pseudocompounds
        | that are futher apart than solvus_tolerance are considered to be
        | distinct true phases). 

        | CAUTION! solvus_tolerance must be greater than the pseudocompound
        | spacing specified for the solution models under consideration, 
        | otherwise compositionally adjacent pseudocompounds may be identified
        | as distinct phases and this will generate confusing output from 
        | WERAMI and PSVDRAW.

        | this keyword may take numeric values: 0->1 

solvus_tolerance 0.1

        | this keyword is only relevant for VERTEX
|---------------------------------------------------------------------

        | the zero_mode keyword specifies the value below which the molar 
        | amount of a phase is considered to be zero. if this option is 
        | turned on (i.e., it's numeric value is greater than zero) stable
        | phases present in amounts below the zero_mode value are eliminated
        | from the output. this option is particularly useful for fractionation
        | calculations as such caculations may result in degenerate compositions
        | (i.e., a composition in which the amount of one or more of the 
        | components is zero).
 

        | CAUTION! because this option is currently implemented after 
        | computations by VERTEX, PSVDRAW may draw boundaries within
        | a single coherent phase field.

        | this keyword may take numeric values: 0->1, to turn this option off
        | assign zero_mode a negative value.  

zero_mode 1e-6

        | this keyword is only relevant for WERAMI/PSVDRAW
|---------------------------------------------------------------------