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Dataplot Vol 1 Vol 2


PARAMETER EXPANSION (SET)

Name:
    PARAMETER EXPANSION (SET)
Type:
    Set Subcommand
Purpose:
    Specify whether parameters substituted for by the "^" character are expanded into a numeric or exponential format.
Description:
    The "^" is normally used to substitute parameters into text strings for various types of labels. For this reason, a limited amount of precision is maintained.

    The "^" can also be used to define a constant in a fit. In this case, more precision may be necessary. Setting PARAMETER EXPANSION to EXPONENTIAL will substitute the number as

      (0.number*10**(exp))
    where number and exp are the values for the number in scientific notation.

    In brief, setting this parameter to EXPONENTIAL is sometimes needed for fits. For all other purposes, you typically want this parameter set to NUMERIC.

Syntax:
    SET PARAMETER EXPANSION <value>
    where <value> is NUMERIC or EXPONENTIAL.
Examples:
    SET PARAMETER EXPANSION EXPONENTIAL
    SET PARAMETER EXPANSION NUMERIC
Default:
    The default is NUMERIC.
Synonyms:
    None
Related Commands:
    ^ = Substitution character.
    PARAMETER EXPAND DIGITS (SET) = Specify the number of digits to the right of the decimal point when performing a parameter substitution.
    FIT = Perform linear and non-linear fits.
Applications:
    Fitting
Implementation Date:
    2000/1
Program:
    read richter.nice1 x y
    .
    set parameter expansion exponential
    let pii = 3.141592654
    let ee = 1.602177*(10**(-19))
    let h = 6.6260755*(10**(-34))
    let hb = h/(2*pii)
    let sn = (ee*ee)/(pii*h)
    .
    .
    let me = 9.10939*(10**(-31))
    let mstar = 0.067*me
    .
    .
    let minsig = 0.0028308966
    let ns = 3.342*(10**(15))
    let mobility = minsig/(ee*ns)
    let taue = mstar*mobility/ee
    let kfermi = sqrt(2*pii*ns)
    let vfermi = kfermi*(hb/mstar)
    let d = (vfermi*vfermi*taue)/2.0
    .
    .
    let taup = 5
    let x0 = 9.36*(10**(-6))
    .
    let function arg1 = (^hb)/(4*(^d)*(^ee)*(taup*(10**(-11)))*abs(x-x0))
    let function arg2 = (^hb)/(4*(^d)*(^ee)*(^taue)*abs(x-x0))
    let function arg3 = (taup*(10**(-11)))/(^taue)
    .
    let function f0 = (digamma(0.5+arg1)-digamma(0.5+arg2)+log(arg3))
    let function f = (^sn)*(f0)+(^minsig)
    .
    fit y=f

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Date created: 06/05/2001
Last updated: 11/02/2015

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