ZDD : Overview of ZDD Operators and Methods : import : Import ZDD

3.28 import : Import ZDD

Format

$obj$ .import( $fileName$ ) $\rightarrow zdd$

$fileName$ : string

Description

Import restores the serialised output of ZDD object $zdd$ object previously saved in the ZDD file (defined at fileName) with the export method.

The declaration order of symbols during import must be defined in the same order during export.

Examples

Example 1: Basic Example

> require 'zdd'
> a=ZDD::itemset("a")
> b=ZDD::itemset("b")
> c=ZDD::itemset("c")
> f=5*a*b*c+3*a*b+2*b*c+c
> f.show
 5 a b c + 3 a b + 2 b c + c
> f.export("dat.zdd")
# Contents in the export file dat.zdd are as follows. 
# _i 3
# _o 3
# _n 7
# 4 1 F T
# 248 2 F 5
# 276 3 4 248
# 232 2 F 4
# 2 2 F T
# 272 3 232 2
# 268 3 232 248
# 276
# 272
# 268

Example 2: Example of correctly restored file

> require 'zdd'
# After sybmol is declared in order, import correctly restores the file. 
> ZDD::symbol("a")
> ZDD::symbol("b")
> ZDD::symbol("c")
> g1=ZDD::import("dat.zdd")
> g1.show
 5 a b c + 3 a b + 2 b c + c

Example 3: Example of incorrectly restored file

> require 'zdd'
# If item b,c are not declared in order, b and c will be represented incorrectly
# in the results.
> ZDD::symbol("a")
> ZDD::symbol("c")
> ZDD::symbol("b")
> g2=ZDD::import("dat.zdd")
> g2.show
 5 a c b + 3 a c + 2 c b + b

Example 4: Restore file without symbol declaration

> require 'zdd'
# Item names such as x1,x2,x3 will be used if the symbols are not declared before import. 
# In this case, the sequence number followed after x will be in reverse order
# corresponding to the declaration order of the item.
# In the following example, x1=c, x2=b, x3=c.
> g3=ZDD::import("dat.zdd")
> g3.show
 5 x3 x2 x1 + 3 x3 x2 + 2 x2 x1 + x1

See Also

export : Serialized output of ZDD