 Dataplot Vol 1 Vol 2

# PARAMETER EXPAND DIGITS

Name:
PARAMETER EXPAND DIGITS (SET)
Type:
Set Subcommand
Purpose:
Specify the number of digits to the right of the decimal point when parameters are substituted by the "^" keyword.
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.

The SET PARAMETER EXPAND DIGITS command can be used to specify exactly how many digits to use after the decimal point. Note that trailing digits will be included.

Syntax:
SET PARAMETER EXPAND DIGITS <value> where <value> is a numeric value.

If <value> is -1, then Dataplot will automatically determine the number of digits to use. If <value> is 0, the parameter will be expanded to an integer value. If <value> is a positive integer value, then the parameter will be expanded with <value> digits to the right of the decimal point.

Examples:
SET PARAMETER EXPAND DIGITS 8
SET PARAMETER EXPAND DIGITS -1
Note:
The command SET PARAMETER EXPANSION EXPONENTIAL can be used to expand the parameter in exponential format. This can be useful when expanding the parameter in numerical computations (e.g., fitting).
Note:
The 2016/05 version of Dataplot expanded the default parameter expansion to handle up to 9 digits (prior to this, the limit was 6 digits).

The 2016/05 version also increased the number of digits that can be used by the SET PARAMETER EXPAND DIGITS command from 9 to 15.

One distinction is that the default expansion does not include trailing zeros. If the SET PARAMETER EXPAND DIGITS command is used, trailing zeros will be included.

Default:
The default is -1 (i.e., Dataplot automatically determines the number of digits to use).
Synonyms:
None
Related Commands:
 ^ = Substitution character. PARAMETER EXPANDSION (SET) = Specify whether parameter expansions are generated in real format or exponential format.
Applications:
Plot Labeling
Implementation Date:
2005/02 2016/05: Increase maximum number of digits from 9 to 15.
Program:
```
let a = .0001
print "a = ^a"
.
let a = .00001
print "a = ^a"
.
let a = .000001
print "a = ^a"
.
let a = .0000001
print "a = ^a"
.
let a = .00000001
print "a = ^a"
.
let a = .000000001
print "a = ^a"
.
let a = .0000000001
print "a = ^a"
.
set parameter expand digits 9
let a = .000000001
print "a = ^a"
.
set parameter expand digits 10
let a = .0000000001
print "a = ^a"
.
set parameter expand digits 12
let a = .000000000001
print "a = ^a"
```
The following output is generated.
``` THE COMPUTED VALUE OF THE CONSTANT A        =   0.1000000E-03

a = 0.0001

THE COMPUTED VALUE OF THE CONSTANT A        =   0.1000000E-04

a = 0.00001

THE COMPUTED VALUE OF THE CONSTANT A        =   0.1000000E-05

a = 0.000001

THE COMPUTED VALUE OF THE CONSTANT A        =   0.1000000E-06

a = 0.0000001

THE COMPUTED VALUE OF THE CONSTANT A        =   0.1000000E-07

a = 0.00000001

THE COMPUTED VALUE OF THE CONSTANT A        =   0.1000000E-08

a = 0.000000001

THE COMPUTED VALUE OF THE CONSTANT A        =   0.1000000E-09

a = 0

THE FORTRAN COMMON PARAMETER PARAEXPA HAS JUST BEEN SET TO        9

THE COMPUTED VALUE OF THE CONSTANT A        =   0.1000000E-08

a = 0.000000001

THE FORTRAN COMMON PARAMETER PARAEXPA HAS JUST BEEN SET TO       10

THE COMPUTED VALUE OF THE CONSTANT A        =   0.1000000E-09

a = 0.0000000001

THE FORTRAN COMMON PARAMETER PARAEXPA HAS JUST BEEN SET TO       12

THE COMPUTED VALUE OF THE CONSTANT A        =   0.1000000E-11

a = 0.000000000001
```

NIST is an agency of the U.S. Commerce Department.

Date created: 05/26/2016
Last updated: 05/26/2016