Re: [Boost-users] boost transfer pointers by serialize

Subject: Re: [Boost-users] boost transfer pointers by serialize
From: Jack Bryan (dtustudy68_at_[hidden])
Date: 2010-08-29 17:19:44

thanks, 
In this way, in myClass, I replace " double* myDouble" with " serializable_double myDouble". Can the " myDouble " be accessed as the original " double* " ? 
I need to assign some values to myDouble at first and then use boost MPI to transfer it to another process. 
For example,
if I use double*
double myVar =2.1 ;double* myDouble =  &myVar ;
if I use  serializable_double , I need to do it in this way :
double myVar = 2.1 ;serializable_double  myDouble =  &myVar ;
If I am wrong, please correct me. 
The following is the data structure that I want to transfer from one process to another process : -------------------------------------------------------------------------------
typedef struct {    int 	rank;    double 	constr_violation;    double 	*xreal;    int 	**gene;    double 	*xbin;    double 	*obj;    double 	*constr;    double 	crowd_dist;   }individual;
typedef struct {    individual *ind;}population;-----------------------------------------------------------------------------------
I need to trasfer population from process 1 to process 2 such that the data members in population->ind can be operated in process 2.
Then, the process 2 returns the population->ind  with new results  to process 1. 
Becasue the population and individual data structure are also used by other programs in the same project, I do not want to change double8 to serializable_double inside them.
May I use assignment to do it ?
for example, 
myClass{
    int 			rank;    double 			constr_violation;    serializable_double   	xreal;    serializable_int 		*gene;     serializable_double 	xbin;    serializable_double 	obj;    serializable_double 	constr;    double 			crowd_dist;} myObject;
myObject.xreal = (population->ind)->xreal;
Any help is appreciated. 
thanks
Jack 
Aug. 29 2010
To: boost-users_at_[hidden]
From: ramey_at_[hidden]
Date: Sun, 29 Aug 2010 10:27:57 -0800
Subject: Re: [Boost-users] boost transfer pointers by serialize

Jack Bryan wrote:
> Thanks
> 
> 
> Is the m_sd a 
pointer that points to a double variable ?
 
no

> 
> 
> How to refer to the values pointed by m_sd 
?
 
if you use BOOST_SERIALIZE_STRONG_TYPEDEF 
then
the serializable_double can be handled exactly like a 
double.
(note: this is the way it is for integer types. As I write 
this
I'm not sure it applies to floating point types but I 
think it does.
 
think of strong typedef as the same as a typedef except 
that
it actually creates a new identifiable type.
 
 
> For example, I transfer myClass from process 1 to process 2 :
> 

> 
> In process 1, I declear
> 
> 
> 
myClass
> {
> serializable_double m_sd;
> 
> 
> 
serializable_int m_sint;
> 
> 
> template<class 
Archive>
> void serialize(Archive &ar, const unsigned int 
version){
> ar & m_sd & m_sint;;
> }
> } 
myObject;
> 

so far so good.
 

> In process 1 , I use
> 
> 
> 
world.isend(destRank, downStreamTaskTag, myObject);
> 
> 
> In 
process 2, I use
> 
> 
> world.recv(sourceRank, 
downStreamTaskTag, myObjectRecv);
> 
> 
> How to refer to the 
values pointed by m_sd in myClass ?
 
just like you would doubles.

> 
> 
> May I use it in this way ?
> 
> 

> *(myObjectRecv.m_sd) ;
 
you could. 

> If myObjectRecv.m_sd  is an address of a primitive 
variable,
> the address should be in process 1's memory space.
> 

> 
> How does the process 2 can modify the value of the 
variable
> pointed by a pointer with address in process 1's memory space 
?
 
no it will be in the address space of the process that 
does
the de-serialization.

> 
> I can 
use the similar way to do it for pointer's pointer ?
> such as double** 
?
 
unfortunately, pointers to pointers are not currently 
serializable.
There is a track item on this.  This is an oversight 
in the implementation
which is non-trivial to fix.

> Any help is appreciated ?

it is?
 
Robert Ramey
 

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