i am trying to get emg and force data simultaneously using parallel computing tool box but i am unable to read the data???

i am using the below code

if matlabpool('size') == 0

        matlabpool open local 2
data1=zeros([122880,2]);
data2=zeros([37000,1]);

spmd

    switch labindex
        case 1
           s = daq.createSession('ni');
s.addAnalogInputChannel('cDAQ2Mod1', 0, 'Voltage');
s.addAnalogInputChannel('cDAQ2Mod1', 1, 'Voltage');
s.Rate = 2048
s.DurationInSeconds = 60;
labBarrier
[data1,time] = s.startForeground;

 case 2
          delete(instrfindall);
s = serial ( 'COM5', 'BaudRate', 115200);
set(s, 'Timeout',60);
s.InputBufferSize =37000;
labBarrier
fopen(s);
data2=fread(s);  

    end

end

end

matlabpool close

my workspace is containing data in composite form

data1 composite

data2 composite

is there any way to solve this problem???

[avinash pabbireddy]

Values returning from the body of an spmd statement are converted to Composite objects on the MATLAB client. A Composite object contains references to the values stored on the remote MATLAB workers, and those values can be retrieved using cell-array indexing. The actual data on the workers remains available on the workers for subsequent spmd execution, so long as the Composite exists on the client and the parallel pool remains open.

[Edric Ellis]

What is the problem? You can access the elements of data1 and data2 using indexing, like so

>> data1{1} % get a single element
>> data2(:) % get all elements as a cell array

[avinash pabbireddy]

 data1(1);
Error using Composite/subsref (line 23)
Either the Composite has been saved and then loaded, or
the matlabpool for that Composite has been closed.

[avinash pabbireddy]

can u tell me the way to get data??

[avinash pabbireddy]

Error using Composite/subsref (line 48) An invalid indexing request was made

Error in sync (line 44) E=data1(:);

Caused by: Error using Composite/subsref>iCheckValuesExist (line 86) The Composite has no value on the following lab(s): 2 .

Answer 1

[Edric Ellis]

The data contained within a Composite is retained on the workers. Therefore if you close the pool, the data goes away. So, you simply need to avoid closing the pool until you've got the data from the workers. One way to do this would be:

data1 = data1(:);
data2 = data2(:);
matlabpool close

Or, you could simply leave the matlabpool open.

[avinash pabbireddy]

here i am changing the above lines [data1,time] = s.startForeground;

data2=fread(s); to

[data1(:)] = s.startForeground;

[data2(:)]=fread(s);

but in the workspace i am not able to see the data and i am not using matlabpool close

[avinash pabbireddy]

data1(:)

ans =

    [122880x2 double]
    [122880x2 double]

>> data2(:)

ans =

    [37000x1 double]
    [37000x1 double]

[Walter Roberson]

That sounds like you got the results out, each one being a 2 x 1 cell array each entry of which contains a 122880x2 matrix ?

[avinash pabbireddy]

if matlabpool('size') == 0 matlabpool open local 2

spmd

    switch labindex
        case 1
           s = daq.createSession('ni');
s.addAnalogInputChannel('cDAQ2Mod1', 0, 'Voltage');
s.addAnalogInputChannel('cDAQ2Mod1', 1, 'Voltage');
s.Rate = 2048
s.DurationInSeconds = 60;
labBarrier
data1 = s.startForeground;
case 2
          delete(instrfindall);
s = serial ( 'COM5', 'BaudRate', 115200);
set(s, 'Timeout',60);
s.InputBufferSize =37000;
labBarrier
fopen(s);
data2=fread(s);
    end

end

E1=data1(:,1);

E2=data1(:,2);

F=data2(:);

celldisp(F);

end

matlabpool close

[avinash pabbireddy]

Caused by: Error using Composite/subsref>iCheckValuesExist (line 86) The Composite has no value on the following lab(s): 2 .

[Walter Roberson]

Assign each variable on each of the labs, even it is just assigning [] to it.

data1 = s.startForeground;
data2 = [];
...

[avinash pabbireddy]

i am able to get data using data1=data1{:,1}; data2=data2{:,2}; thank you @walter roberson @edric ellis