Method checkKernelForMemLeak

tfjs-core/src/engine.ts:561–588

(
      kernelName: string, numDataIdsBefore: number,
      outInfos: TensorInfo[])

  }

  private checkKernelForMemLeak(
      kernelName: string, numDataIdsBefore: number,
      outInfos: TensorInfo[]): void {
    const numDataIdsAfter = this.backend.numDataIds();

    // Count the number of data ids associated with the result of the kernel.
    let numOutputDataIds = 0;
    outInfos.forEach(info => {
      // Complex numbers allocate 3 data ids, one for 'real', one for
      // 'imaginary', and one for the container that holds the former two.
      numOutputDataIds += (info.dtype === 'complex64' ? 3 : 1);
    });

    // Account for the number of moves during kernel execution. A "data move"
    // can happen in the middle of a kernel execution, placing a new (key,value)
    // pair in the data storage. Since data moves have net zero effect (we
    // always remove the data from the old backend), we have to cancel them out
    // when detecting memory leaks.
    const numMoves =
        this.state.numDataMovesStack[this.state.numDataMovesStack.length - 1];
    const dataIdsLeaked =
        numDataIdsAfter - numDataIdsBefore - numOutputDataIds - numMoves;
    if (dataIdsLeaked > 0) {
      throw new Error(
          `Backend '${this.backendName}' has an internal memory leak ` +
          `(${dataIdsLeaked} data ids) after running '${kernelName}'`);
    }
  }

  /**
   * Internal helper method to execute a kernel Func