﻿ Problem Descriptor Reference > The Elements of a Descriptor > Numeric Constants

# Numerical Constants   Integers

Integers must be of the form XXXXXX where X is any decimal digit from 0 to 9.  Integer constants can contain up to 9 digits.

Decimal Numbers

Decimal numbers must be of the form XXXXX.XXX where X is any decimal digit from 0 to 9 and '.' is the decimal separator.  Decimal numbers must not include commas ','. Using the European convention of a comma ',' as a decimal separator will result in an error.  Commas are reserved as item separators.  Decimal numbers may include zero to nine digits to the left of the decimal separator and up to a total of 308 digits total.  FlexPDE considers only the first fifteen digits as significant.

Engineering Notation Numbers

Engineering notation numbers must be of the form XXXXXEsYYY  where X is any digit from 0 to 9 or the decimal separator '.', Y is any digit from 0 to 9, E is the exponent separator, and s is an optional sign operator.  Engineering notation numbers must not include commas ','. Using the European convention of a comma ',' as a decimal separator will result in an error.  Commas are reserved as item separators.  The number to the left of the exponent separator is treated as a decimal number and the number to the right of the exponent separator is treated as an integer and may not contain a decimal separator or more than 3 digits.   The range of permitted engineering notation numbers is 1e-307 to 1e308.