Fig. 4: Experimental results for pattern classification.

a A portion of the crossbar circuit is utilized in a 64 × 10 single-layer perceptron MNIST image classification experiment. b Examples of target and (c) actual conductances after tuning with a 1% relative error. d Measured classification fidelity and its comparison with simulation results as a function of weight import accuracy. In each simulation trial, the weights are selected randomly from a range of target_value × [1 − tuning_error, 1 + tuning_error]. e, f Measured output currents for all ten outputs over the 10-s interval for patterns ‘7’ and ‘9’ (shown in the corresponding insets) for the experiment with a 1% relative tuning error. The currents are measured, one row at a time, by simultaneously applying input voltages on all 64 columns and grounding 10 specified rows. See Fig. 3 caption for the definition of relative tuning error.