Boost logo

Boost Users :

Subject: Re: [Boost-users] boost C++ load data from file
From: Jack Bryan (dtustudy68_at_[hidden])
Date: 2010-07-13 00:54:47

Thanks for your code,
I am working on a multi-computer Open MPI cluster system.
If I put these data files in /home/mypath/folder, is it possible that all non-head nodes can access the files in the folder ?
I need to load some data to some nodes, if all nodes can access the data, I do not need to load them to each node one by one.
If multiple nodes access the same file to get data, is there conflict ?
For example,
fopen(myFile) by node 1, at the same time fopen(myFile) by node 2.
Is it allowed to do that on MPI cluster without conflict ?
Are there some boost MPI routines to support this ?
I cannot find them in
Any help is appreciated.
July 12 2010
From: binglongx_at_[hidden]
To: boost-users_at_[hidden]
Date: Tue, 13 Jul 2010 00:01:52 -0400
Subject: Re: [Boost-users] boost C++ load data from file

It's a wide shot without an example of your specific data
organization, but this is something that might give your desired indexing
(being efficient or not is disregarded here):
using namespace std; // excuse: just for
typedef ... POWC; // What's the underlying type of this
typedef map<POWC, float> PowcFloat;
typedef map<int,
PF> YearPowcFloat;
typedef map<string, YearPowcFloat>
void load(const vector<string>& states, const
vector<int>& years, const vector<POWC>& powcs, Jumbo&
 BOOST_FOREACH(const string& state,
  BOOST_FOREACH(int year,
i=0; i<40;
ppf = ...; // populate ppf with each float from
void test_load()
powcs(40); // ...
 Jumbo big;
 load(states, years, powcs,
 cout<<"New York 2010 powcs[0] = "<<
big["NewYork"][2010][powcs[0]] << endl;

From: Jack Bryan
Sent: Monday, July 12, 2010 3:04 PM
To: boost-users_at_[hidden]
Subject: [Boost-users] boost C++ load data from

Dear All,

I need to load data (24 X 28 X 40) from 24 X 28 files into a datastructure
so that my program can use
them to do operations.

Each file has 40 data items, which are floating numbers.

I hope that the data structure can be indexed by item name not only by

For example, for 24 states in USA, each state's power consumption is POWC
in year Y.

I hope that the data structure indexing is like this


My question is :

(1) how to load the data from 24 x 28 files by boost C++?

It is boring to type file's name one by one in program.

Is there an alternative to load the data by indexing the file names

for example,

for (filename = name1; filename < filenum ; filename++)
load data from
store loaded
data in the datastructure.

(2) how to index the item of the datastructure by boost C++ ?

Any help is appreciated.


July 11 2010

Hotmail is redefining busy with tools for the New Busy. Get more from your
inbox. See how.

Boost-users mailing
The New Busy is not the old busy. Search, chat and e-mail from your inbox.

Boost-users list run by williamkempf at, kalb at, bjorn.karlsson at, gregod at, wekempf at