SPSS® 12.0 Command Syntax Reference

NLR 1057
PCON n Convergence criterion for the parameter values. Specify any non-negative
number for n. The default is 1E – 8 . If successive iterations fail to change
any of the parameter values by this proportion, the procedure stops. Specify
0 to disable this criterion.
RCON n Convergence criterion for the correlation between the residuals and the
derivatives. Specify any non-negative number for n. The default is 1E – 8 .
If the largest value for the correlation between the residuals and the derivatives
equals this value, the procedure stops because it lacks the information
it needs to estimate a direction for its next move. This criterion is often
referred to as a gradient convergence criterion. Specify 0 to disable this
criterion.
Example
MODEL PROGRAM A=.5 B=1.6.
COMPUTE PRED=A*SPEED**B.
NLR STOP /CRITERIA=ITER(80) SSCON=.000001.
• CRITERIA changes two of the five cutoff values affecting iteration, ITER and SSCON, and
leaves the remaining three, PCON, RCON, and CKDER, at their default values.
BOUNDS Subcommand
The BOUNDS subcommand can be used to specify both linear and nonlinear constraints. It
can be used only with CNLR; it cannot be used with NLR.
Simple Bounds and Linear Constraints
BOUNDS can be used to impose bounds on parameter values. These bounds can involve
either single parameters or a linear combination of parameters and can be either equalities or
inequalities.
• All bounds are specified on the same BOUNDS subcommand and separated by
semicolons.
• The only variables allowed on BOUNDS are parameter variables (those named on MODEL
PROGRAM).
• Only * (multiplication), + (addition), – (subtraction), = or EQ, >= or GE, and = A;
B >= 9;
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