Constraits allow you to automatically update parameters during your fit. Constraints can be simple, such as restricting a layer depth to a particular range, or complex, tying the value of one layer to another.
After changing constraints, click Update so that the new constraints will be used. Click Apply to apply the constraints to the current configuration.
At present constraints need to be entered as Tcl code. This will change eventually to a simple language which can be translated to C, Tcl, Python or whatever implementation language we are using, so be prepared to update your constraints as program versions change. No checks are done that the constraint code is correct, so be careful!
The usual Tcl syntax applies.
set <var> [expr {<expression>}]
if { <expression> } {
statements
} else {
statements
}
foreach <var> { list } {
statements
}
while { <expression> } {
statements
}
We define a function [range 1 $n] which returns a list of numbers from one to n. This is useful when operating on every layer.
Layer parameters are referenced using:
gmlayer set <par> <value>
If value is missing, the layer parameter is returned, otherwise the layer parameter is updated and returned.
The following parameters are available for reflfit:
ntl nml nbl
bk bi vqc
tdi troi tmui tqci for i in 1 to 9
mdi mroi mmui mqci for i in 1 to 9
bdi broi bmui bqci for i in 1 to 9
The following parameters are available for reflpol:
nl
bk bi vqc
di roi mui qci for i > 0
dmi rmi thi qmi for i > 0
Example:
# set depth of layer T2 to be equal to layer M1
gmlayer set td2 [gmlayer set md1]
# set roughness to 1/2 the layer depth for all layers
foreach i [range 1 [gmlayer set ntl]] {
gmlayer set tro$i [expr {[gmlayer set td$i]/2}]
}
foreach i [range 1 [gmlayer set nml]] {
gmlayer set mro$i [expr {[gmlayer set md$i]/2}]
}
foreach i [range 1 [gmlayer set nbl]] {
gmlayer set bro$i [expr {[gmlayer set bd$i]/2}]
}
# set the total depth of the middle layers to be equal
# to the total depth of the top layers while preserving
# the relative depths of the middle layers
set sumt 0
foreach i [range 1 [gmlayer set ntl]] {
set sumt [expr {$sumt + [gmlayer set td$i]}]
}
set summ 0
foreach i [range 1 [gmlayer set nml]] {
set summ [expr {$summ + [gmlayer set md$i]}]
}
set scale [expr {$sumt/$summ}]
foreach i [range 1 [gmlayer set nml]] {
gmlayer set tm$i [expr {[gmlayer set tm$i]*$scale}]
}
2003-09-16