Method backwardsFunc

tfjs-core/src/engine.ts:1190–1208

(dy: T, saved: Tensor[])

      };

      const backwardsFunc = (dy: T, saved: Tensor[]) => {
        const gradRes = res.gradFunc(dy, saved);
        const grads: Tensor[] = Array.isArray(gradRes) ? gradRes : [gradRes];
        util.assert(
            grads.length === inputs.length,
            () => 'The function f passed in customGrad(f) must return an ' +
                'object where `obj.gradFunc` is a function that returns ' +
                'the same number of tensors as inputs passed to f(...).');
        util.assert(
            grads.every(t => t instanceof Tensor),
            () => 'The function f passed in customGrad(f) must return an ' +
                'object where `obj.gradFunc` is a function that returns ' +
                'a list of only tensors.');
        const gradMap: {[key: string]: () => Tensor} = {};
        grads.forEach((grad, i) => {
          gradMap[i] = () => grad;
        });
        return gradMap;
      };

      return this.runKernelFunc({
        forwardFunc,