public void basic_backprop_with_1_node()
{
ENV.engine = new Engine();
var x = alb.scalar(0);
var y = alb.scalar(1);
var dy = alb.scalar(1);
Dictionary <int, Tensor> accumulatedGradientsMap = new Dictionary <int, Tensor>();
accumulatedGradientsMap.Add(y.id, dy);
var input1 = new System.Collections.Generic.Dictionary <string, Tensor>();
input1.Add("x", x);
TapeNode[] tape = new TapeNode[] {
new TapeNode()
{
gradient = (Tensor dy2) =>
{
NamedGradientMap ngm = new NamedGradientMap();
ngm.gradient.Add("x", () =>
{
return(dy2.add(alb.scalar(1)));
});
return(ngm);
}
, id = 0
, inputs = input1,
name = "node0",
output = y
}
};
Tape.backpropagateGradients(accumulatedGradientsMap, tape);
AssertTools.ArrayIsEqual(accumulatedGradientsMap[x.id].dataSync(), new float[] { 2 });
}
public static void basic_backprop_with_a_split_node_accumulates_gradients()
{
ENV.engine = new Engine();
var x = alb.scalar(0);
var intermediate1 = alb.scalar(1);
var intermediate2 = alb.scalar(2);
var y = alb.scalar(3);
var dy = alb.scalar(1);
Dictionary <int, Tensor> accumulatedGradientsMap =
new Dictionary <int, Tensor>();
accumulatedGradientsMap.Add(y.id, dy);
TapeNode node0 = new TapeNode();
node0.id = 0;
node0.name = "node0";
node0.inputs = new Dictionary <string, Tensor>();
node0.inputs.Add("x", x);
node0.output = intermediate1;
node0.gradient = (Tensor dy2) =>
{
NamedGradientMap ngm = new NamedGradientMap();
ngm.gradient.Add("x", () =>
{
return(dy2.add(alb.scalar(1)));
});
return(ngm);
};
TapeNode node1 = new TapeNode();
node1.id = 1;
node1.name = "node1";
node1.inputs = new Dictionary <string, Tensor>();
node1.inputs.Add("x", x);
node1.output = intermediate2;
node1.gradient = (Tensor dy2) =>
{
NamedGradientMap ngm = new NamedGradientMap();
ngm.gradient.Add("x", () =>
{
return(dy2.add(alb.scalar(1)));
});
return(ngm);
};
TapeNode node2 = new TapeNode();
node2.id = 2;
node2.name = "node2";
node2.inputs = new Dictionary <string, Tensor>();
node2.inputs.Add("intermediate1", intermediate1);
node2.inputs.Add("intermediate2", intermediate2);
node2.output = y;
node2.gradient = (Tensor dy2) =>
{
NamedGradientMap ngm = new NamedGradientMap();
ngm.gradient.Add("intermediate1", () =>
{
return(dy2.add(alb.scalar(1)));
});
ngm.gradient.Add("intermediate2", () =>
{
return(dy2.add(alb.scalar(1)));
});
return(ngm);
};
TapeNode[] tape = new TapeNode[] { node0, node1, node2 };
Tape.backpropagateGradients(accumulatedGradientsMap, tape);
AssertTools.ArrayIsEqual(accumulatedGradientsMap[x.id].dataSync(), new float[] { dy.dataSync()[0] + 5 });
}
