Does the network learn based on previous training or does it restart? Matlab, neuralnetworks
It trains again based on what it learned the first time you did OP = train(OP,inputsVals,targetVals). More generally, train uses your network's weights, i.e. it does not initialize the weights. The weight initialization happens in feedforwardnet.

Example:

% To generate reproducible results 
% http://stackoverflow.com/a/7797635/395857
rng(1234,'twister')

% Prepare input and target vectors
[x,t] = simplefit_dataset;

% Create ANN
net = feedforwardnet(10);

% Loop to see where train() initializes the weights
for i = 1:10

    % Learn
    net.trainParam.epochs = 1;
    net = train(net,x,t);

    % Score
    y = net(x);
    perf = perform(net,y,t)
end


yields

perf =

    0.4825


perf =

    0.0093


perf =

    0.0034


perf =

    0.0034


perf =

    0.0034


perf =

    0.0034


perf =

    0.0034


perf =

    0.0034


perf =

    0.0034


perf =

    0.0028