| comments are preceded by the "|" character |------------------------------------------------------------------------------ |Section 1: I/O composition, problem type, computational mode variables: mass | "molar" or "mass" (weight) compositional input units, | the choice specified here overrides the specification (iwt) in the | definition file. invptx | inversion problem type: "invptx" => inverse thermobarometry | "invxpt" => invert experimental data minim | inversion method: "minim" => Nelder-Meade minim algorithm | "grid" => grid search likelihood | criterion for selecting best result: "likelihood" => minimum | value of the objective function; "bayes" => minimum value of | the objective function weighted by prior probability hot | cold => compute uncertainties at a user specified (e.g., previously computed) | inversion coordinate. hot => automatically compute incertainties for the best model | obtained during the NTRY (see below) inversions. Both "cold" and "hot" require NUNC > 0 | (see below, Section 3). JADC | "GRH" => use George's normalization, etc | "JADC" => use my normalization, etc all | "better" => output only results that improve on the previous best result | "all" => output all results vital_sign | "vital_sign" => output optimization counter to console | "quiet" => no counter no_seed | "seed" => generate a new seed for random number generation each time the | program is run. "no_seed" => for reproducible sequences (e.g., for debugging). miss_ok | "no_miss" => reject models wherein an observed phase is not predicted; "miss_ok" | => allow models such model. abs_err | "rel_err" => uncertainties are fractional error. "abs_err" => uncertainties | are absolute. use_central |------------------------------------------------------------------------------ | Section 2: Objective function mode, tolerances, and weights Chi | Chi => use Chi-square (r^2/xhat); wChi => use weighted Chi square (r/sig)^2. wChi | is optimal if accurate uncertainties are available, othewise Chi. NB: this choice | may affect oktol and invtol (below). quadratic | "quadratic" or "linear". quadratic => objective function is a quadratic | function of residuals. "linear" => objective function is linear for | residuals > 1. NB: this choice may affect oktol and invtol (below). 1d5 | oktol, the maximum acceptable value of the objective function, larger values trigger an error 1d0 1d-3 | invtol, the maximum value of the objective function for an acceptable solution 1d0 | wcomp, compositional residual weight 1d4 | wextra, extra phase amount residual weight, wextra should be ~ 1/eps^2, | where eps is the error on modal estimates (~0.01) 1d3 | wmiss, missing phase residual weight, chosen so that extra and missing | phases have comparable contributions to the objective function. | the above weights have the consequence that: | when the predicted phases match the observed phases within compositional uncertainty | the objective function will be < 1 | when the observed phases are predicted but additional phases are also predicted | the objective function will be > 1 | when an observed phase is not predicted the objective function will be of order wmiss. |------------------------------------------------------------------------------ | Section 3: Monte-Carlo logistical variables: 10 | MTRY, number of starting guesses used to find a best fit model 20 | NUNC, number of perturbations to evaluate uncertainities. set nunc = 0 | to suppress uncertainty evaluation. 4 | PTRY, number of starting guesses used to find a best fit perturned model. | for well-conditioned problems set MTRY to 1. | time cost is proportional to the number of Nelder-Meade minimizations | which is ntry + (nunc * mtry). | Each Nelder-Meade minimization is allowed to do a maximum of kcount | free energy minimization calculations plus a few extra (~10-50) if | the minimum is to be fit to a surface (iquad = 1). I see | little value to the surface fitting, who cares if it's at a true | minimum? The result is still useful if it's better than the other | results. |------------------------------------------------------------------------------ | Section 4: Nelder-Meade MINIM algorithm variables 1d-6 | simplx, if iquad = 1, criterion used to decide whether final simplex is expanded before quadratic fitting, should be at least 1000 x rounding error 0.1 | frac, fractional step size 10 | conchk, how often to check for convergence 0 | iprint, 0 => normal print, < 0 => silent, > 0 => verbose 0 | iquad, 1 => fit quadratic surface to improve location of the minimum, 0 => don't fit 1000 | kcount, max # of objective evaluations per try, recommended nparm*1024 |------------------------------------------------------------------------------ | Section 5: Thermobarometric problem definition | blmc1 invert to PT with bulk, two known phase compositions, and no penalty | for additional phases (by setting wextra = 0 in section 3) begin_assemblage | this tag signals the beginning of the problem definition sample_name bl_with_full_bulk pressure_range 10000 30000 | bar, pressure range of initial guesses temperature_range 573 973 | K, temperature range of initial guesses redox_component O2 | optional keyword to optimize for an unmeasured component | the following specification is only read if the | unmeasured_redox_component tag is present. begin_limits FeO 0 0.25 | stoichiometric factors after the component name are | express min/max limits on the unmeasured component | in terms of the specified component, e.g. , here | molar O2 >= 0 | molar O2 <= 1/4 molar FeO | if limits are specified, the amount of the unmeasured | component is constrained within these limits. Otherwise | the amount is allowed to vary within the amount above | specified for the unmeasured component. end_limits begin_bulk | begin_bulk/end_bulk is an optional section, if this | section is present it specifies the effective bulk | composition. Na2O 0.713980803 0.014279616 CaO 0.244376396 0.004887528 K2O 0.811771245 0.016235425 FeO 1.799616587 0.035992332 MgO 2.512401975 0.05024804 Al2O3 2.790286978 0.05580574 SiO2 87.7722479 1.755444958 H2O 2.946682343 0.058933647 TiO2 0.318654947 0.006373099 end_bulk | Phase names used here must correspond to the solution models specified in | the problem definition file or to endmember names in the thermodynamic data | file specified in that file. | chlorite phase_name Chl(W) | Modes (phase_mode) are optional, if phase_mode is not specified or its | value is < 0 the constraint is ignored. The first value of phase_mode | is the volume fraction (<1) of the phase, the second number is the uncertainty | of the fraction. If phase modes are specified, then they indicate the | fraction of the phase in the equilibrium assemblage, these fractions do NOT | correspond to bulk fractions unless the specified assemblage represents a | bulk equilibrium. phase_mode -1 0 | Component names used here must match those specified in the problem | definition file. If the phase is an endmember its composition is not | read. begin_comp SiO2 29.105 0.775 Al2O3 16.397 0.806 FeO 20.014 1.477 MgO 15.996 4.6695 CaO 0.183 3.6455 H2O 12.27 0.2454 end_comp | glaucophane phase_name cAmph(G) phase_mode -1 0 begin_comp SiO2 57.778 0.015461653 Al2O3 10.811 0.034106471 TiO2 0.013 0.000676116 FeO 11.06 0.055111125 MgO 10.361 0.020627412 CaO 0.968 0.01241795 Na2O 6.887 0.005827818 K2O 0.025 0.000404451 H2O 2.15 0.043 end_comp | phengite phase_name Mica(W) phase_mode -1 0 begin_comp SiO2 50.97 0.151604118 Al2O3 27.16 0.220582506 FeO 2.819 0.112713515 MgO 3.187 0.070521864 Na2O 0.584 0.054311857 K2O 10.828 0.092198123 H2O 4.32 0.0864 end_comp | Garnet phase_name Gt(W) phase_mode -1 0 begin_comp SiO2 37.745 0.053112134 Al2O3 20.963 0.046484587 FeO 32.003 0.4095057 MgO 2.827 0.105635581 CaO 3.808 0.340225183 end_comp | rutile phase_name ru phase_mode -1 0 | quartz phase_name q phase_mode -1 0 end_assemblage guest1.ceas@iisc.in.ac Guest1ceas@52467 19370.9 884.463 0.466418