#ifndef TH_GENERIC_FILE
#define TH_GENERIC_FILE "generic/TemporalRowConvolution.c"
#else

static inline void THNN_(TemporalRowConvolution_shapeCheck)(
	THNNState *state,
	THTensor *input,
	THTensor *gradOutput,
	THTensor *weight,
	THTensor *bias,
	int kW,
	int dW,
	int padW) {

	THArgCheck(kW > 0, 5,
	           "kernel size should be greater than zero, but got kW: %d", kW);
	THArgCheck(dW > 0, 6,
	           "stride should be greater than zero, but got dW: %d", dW);
	THNN_ARGCHECK(weight->nDimension == 3, 3, weight,
	              "3D weight tensor expected, but got: %s");
    THArgCheck(THTensor_(isContiguous)(weight), 4, "weight must be contiguous");
    THArgCheck(!bias || THTensor_(isContiguous)(bias), 5, "bias must be contiguous");

	if (bias != NULL) {
		THNN_CHECK_DIM_SIZE(bias, 1, 0, weight->size[0]);
	}

	// we're always looking at (possibly batch) x feats x seq
	int ndim = input->nDimension;
	int dimF = 0;
	int dimS = 1;

	if (ndim == 3) {
		++dimS;
		++dimF;
	}

	THNN_ARGCHECK(ndim == 2 || ndim == 3, 1, input,
	              "2D or 3D (batch mode) input tensor expected, but got :%s");

	long inputFrameSize = weight->size[0];
	long nInputFrame = input->size[dimS];
	long nOutputFrame = (nInputFrame + 2 * padW - kW) / dW + 1;

	if (nOutputFrame < 1) {
		THError("Given input size: (%d x %d). "
		        "Calculated output size: (%d x %d). Output size is too small",
		        inputFrameSize, nInputFrame, inputFrameSize, nOutputFrame);
	}

	THNN_CHECK_DIM_SIZE(input, ndim, dimF, inputFrameSize);

	if (gradOutput != NULL) {
		THNN_CHECK_DIM_SIZE(gradOutput, ndim, dimF, inputFrameSize);
		THNN_CHECK_DIM_SIZE(gradOutput, ndim, dimS, nOutputFrame);
	}
}

static void THNN_(unfolded_acc_row)(
	THTensor *finput,
	THTensor *input,
	int kW,
	int dW,
	int padW,
	long inputFrameSize,
	long nInputFrame,
	long nOutputFrame) {

	size_t c;
	real *input_data = THTensor_(data)(input);
	real *finput_data = THTensor_(data)(finput);

// #pragma omp parallel for private(c)
	for (c = 0; c < inputFrameSize; c++) {
		size_t kw, x;
		size_t ix = 0;

		for (kw = 0; kw < kW; kw++) {
			real *src = finput_data
			            + c * (kW * nOutputFrame)
			            + kw * (nOutputFrame);
			real *dst = input_data + c * (nInputFrame);

			ix = (size_t)(kw);
			if (dW == 1) {
			  real *dst_slice = dst + (size_t)(ix);
			  THVector_(cadd)(dst_slice, dst_slice, src, 1, nOutputFrame);
			} else {
				for (x = 0; x < nOutputFrame; x++) {
				  real *dst_slice = dst + (size_t)(ix + x * dW);
				  THVector_(cadd)(dst_slice, dst_slice,
						  src + (size_t)(x), 1, 1);
				}
			}
		}
	}
}

static void THNN_(unfolded_copy_row)(
	THTensor *finput,
	THTensor *input,
	int kW,
	int dW,
	int padW,
	long inputFrameSize,
	long nInputFrame,
	long nOutputFrame) {

	long k;
	real *input_data = THTensor_(data)(input);
	real *finput_data = THTensor_(data)(finput);

// #pragma omp parallel for private(k)
	for (k = 0; k < inputFrameSize * kW; k++) {
		size_t c = k / kW;
		size_t rest = k % kW;
		size_t kw = rest % kW;
		size_t x;
		size_t ix;
		real *dst = finput_data + c * (kW * nOutputFrame) + kw * (nOutputFrame);
		real *src = input_data + c * (nInputFrame);

		ix = (size_t)(kw);
		if (dW == 1) {
			memcpy(dst, src+(size_t)(ix), sizeof(real) * (nOutputFrame));
		} else {
			for (x = 0; x < nOutputFrame; x++) {
				memcpy(dst + (size_t)(x), src + (size_t)(ix + x * dW),
				       sizeof(real) * 1);
			}
		}
	}
}

static void THNN_(TemporalRowConvolution_updateOutput_frame)(
	THTensor *input,
	THTensor *output,
	THTensor *weight,
	THTensor *bias,
	THTensor *finput,
	int kW,
	int dW,
	int padW,
	long inputFrameSize,
	long nInputFrame,
	long nOutputFrame) {

	long i;

	THTensor *output3d = THTensor_(newWithStorage3d)(
		output->storage, output->storageOffset,
		inputFrameSize, -1,
		1, -1,
		nOutputFrame, -1);

	THNN_(unfolded_copy_row)(finput, input, kW, dW, padW,
	                         inputFrameSize, nInputFrame, nOutputFrame);

	THTensor_(zero)(output);

	if (bias != NULL) {
		for (i = 0; i < inputFrameSize; i++)
			THVector_(fill)
			        (output->storage->data + output->storageOffset
			        + output->stride[0] * i,
			        THTensor_(get1d)(bias, i), nOutputFrame);
	}

	THTensor_(baddbmm)(output3d, 1, output3d, 1, weight, finput);

	THTensor_(free)(output3d);
}

void THNN_(TemporalRowConvolution_updateOutput)(
	THNNState *state,
	THTensor *input,
	THTensor *output,
	THTensor *weight,
	THTensor *bias,
	THTensor *finput,
	THTensor *fgradInput,     // unused here but needed for Cuda
	int kW,
	int dW,
	int padW,
	bool featFirst) {

	int ndim = input->nDimension;

	THTensor *tinput;
	if (!featFirst) {
		tinput = THTensor_(newTranspose)(input, ndim - 1, ndim - 2);
		input = THTensor_(newContiguous)(tinput);
	} else {
		input = THTensor_(newContiguous)(input);
	}

	THNN_(TemporalRowConvolution_shapeCheck)(
		state, input, NULL, weight, bias, kW, dW, padW);

	long inputFrameSize = weight->size[0];
	long nInputFrame = input->size[ndim - 1];
	long nOutputFrame = (nInputFrame + 2 * padW - kW) / dW + 1;

	if (ndim == 2) { /* non-batch mode */

		THTensor_(resize3d)(finput, inputFrameSize, kW, nOutputFrame);
		THTensor_(resize2d)(output, inputFrameSize, nOutputFrame);

		THTensor_(zero)(finput);
		THTensor_(zero)(output);

		THNN_(TemporalRowConvolution_updateOutput_frame)
		        (input, output, weight, bias, finput,
		        kW, dW, padW,
		        inputFrameSize, nInputFrame, nOutputFrame);

	} else {
		long T = input->size[0];
		long t;

		THTensor_(resize4d)(finput, T, inputFrameSize, kW, nOutputFrame);
		THTensor_(resize3d)(output, T, inputFrameSize, nOutputFrame);

		THTensor_(zero)(finput);
		THTensor_(zero)(output);

#pragma omp parallel for private(t)
		for (t = 0; t < T; t++) {
			THTensor *input_t = THTensor_(newSelect)(input, 0, t);
			THTensor *output_t = THTensor_(newSelect)(output, 0, t);
			THTensor *finput_t = THTensor_(newSelect)(finput, 0, t);

			THNN_(TemporalRowConvolution_updateOutput_frame)
			        (input_t, output_t, weight, bias, finput_t,
			        kW, dW, padW, inputFrameSize, nInputFrame, nOutputFrame);

			THTensor_(free)(input_t);
			THTensor_(free)(output_t);
			THTensor_(free)(finput_t);
		}
	}

	if (!featFirst) { // NOTE: output will NOT be contiguous in this case
		THTensor_(transpose)(output, output, ndim - 1, ndim - 2);
		THTensor_(free)(tinput);
	}

	THTensor_(free)(input);
}

static void THNN_(TemporalRowConvolution_updateGradInput_frame)(
	THTensor *gradInput,
	THTensor *gradOutput,
	THTensor *weight,
	THTensor *fgradInput,
	int kW,
	int dW,
	int padW,
	long inputFrameSize,
	long nInputFrame,
	long nOutputFrame) {

	THTensor *gradOutput3d = THTensor_(newWithStorage3d)(
		gradOutput->storage, gradOutput->storageOffset,
		inputFrameSize, -1,
		1, -1,
		nOutputFrame, -1);

	// weight:			inputFrameSize x kW x 1
	// gradOutput3d:	inputFrameSize x 1 x nOutputFrame
	THTensor_(baddbmm)(fgradInput, 0, fgradInput, 1, weight, gradOutput3d);
	// fgradInput:		inputFrameSize x kW x nOutputFrame
	THTensor_(free)(gradOutput3d);

	THTensor_(zero)(gradInput);

	THNN_(unfolded_acc_row)(fgradInput, gradInput,
	                        kW, dW, padW,
	                        inputFrameSize, nInputFrame, nOutputFrame);
}

void THNN_(TemporalRowConvolution_updateGradInput)(
	THNNState *state,
	THTensor *input,
	THTensor *gradOutput,
	THTensor *gradInput,
	THTensor *weight,
	THTensor *finput,
	THTensor *fgradInput,
	int kW,
	int dW,
	int padW,
	bool featFirst) {

	int ndim = input->nDimension;

	THTensor *tinput, *tgradOutput;

	if (!featFirst) {
		tinput = THTensor_(newTranspose)(input, ndim - 1, ndim - 2);
		tgradOutput = THTensor_(newTranspose)(gradOutput, ndim - 1, ndim - 2);

		input = THTensor_(newContiguous)(tinput);
		gradOutput = THTensor_(newContiguous)(tgradOutput);

	} else {
		input = THTensor_(newContiguous)(input);
		gradOutput = THTensor_(newContiguous)(gradOutput);
	}

	THNN_(TemporalRowConvolution_shapeCheck)(state, input, gradOutput, weight,
	                                         NULL, kW, dW, padW);

	long inputFrameSize = weight->size[0];
	long nInputFrame = input->size[ndim - 1];
	long nOutputFrame = (nInputFrame + 2 * padW - kW) / dW + 1;

	THTensor_(resizeAs)(fgradInput, finput);
	THTensor_(resizeAs)(gradInput, input);

	THTensor_(zero)(fgradInput);
	THTensor_(zero)(gradInput);

    THTensor *tweight = THTensor_(new)();
    THTensor_(transpose)(tweight, weight, 1, 2);

	if (ndim == 2) {
		THNN_(TemporalRowConvolution_updateGradInput_frame)
		        (gradInput, gradOutput, tweight, fgradInput,
		        kW, dW, padW,
		        inputFrameSize, nInputFrame, nOutputFrame);
	} else {
		long T = input->size[0];
		long t;

#pragma omp parallel for private(t)
		for (t = 0; t < T; t++) {

			THTensor *gradInput_t = THTensor_(newSelect)(gradInput, 0, t);
			THTensor *gradOutput_t = THTensor_(newSelect)(gradOutput, 0, t);
			THTensor *fgradInput_t = THTensor_(newSelect)(fgradInput, 0, t);

			THNN_(TemporalRowConvolution_updateGradInput_frame)
			        (gradInput_t, gradOutput_t, tweight, fgradInput_t,
			        kW, dW, padW,
			        inputFrameSize, nInputFrame, nOutputFrame);

			THTensor_(free)(gradInput_t);
			THTensor_(free)(gradOutput_t);
			THTensor_(free)(fgradInput_t);
		}
	}

    THTensor_(free)(tweight);

	if (!featFirst) { // NOTE: gradInput will NOT be contiguous in this case

		THTensor_(free)(tinput);
		THTensor_(free)(tgradOutput);

		THTensor_(transpose)(gradInput, gradInput, ndim - 1, ndim - 2);
	}

	THTensor_(free)(input);
	THTensor_(free)(gradOutput);

}

static void THNN_(TemporalRowConvolution_accGradParameters_frame)(
	THTensor *gradOutput, THTensor *gradWeight, THTensor *gradBias,
	THTensor *finput, real scale) {

	long i;
	THTensor *gradOutput3d = THTensor_(newWithStorage3d)(
		gradOutput->storage, gradOutput->storageOffset,
		gradOutput->size[0], -1,
		1, -1,
		gradOutput->size[1], -1);

    THTensor *tfinput = THTensor_(new)();
	THTensor_(transpose)(tfinput, finput, 1, 2);
	// gradOutput3d:	inputFrameSize x 1 x nOutputFrame
	// finput:			inputFrameSize x nOutputFrame x kW
	THTensor_(baddbmm)(gradWeight, 1, gradWeight, scale, gradOutput3d, tfinput);
	// gradWeight:		inputFrameSize x 1 x kW
    THTensor_(free)(tfinput);

	if (gradBias != NULL) {
		for (i = 0; i < gradBias->size[0]; i++) {
			long k;
			real sum = 0;
			real *data = gradOutput3d->storage->data
			             + gradOutput3d->storageOffset
			             + i * gradOutput3d->stride[0];
			for (k = 0; k < gradOutput3d->size[2]; k++) {
				sum += data[k];
			}
			(gradBias->storage->data + gradBias->storageOffset)[i]
			        += scale * sum;
		}
	}

	THTensor_(free)(gradOutput3d);

}

void THNN_(TemporalRowConvolution_accGradParameters)(
	THNNState *state,
	THTensor *input,
	THTensor *gradOutput,
	THTensor *gradWeight,
	THTensor *gradBias,
	THTensor *finput,
	THTensor *fgradInput,
	int kW,
	int dW,
	int padW,
	bool featFirst,
	accreal scale_) {

    real scale = TH_CONVERT_ACCREAL_TO_REAL(scale_);
	int ndim = input->nDimension;

	THTensor *tinput, *tgradOutput;

	if (!featFirst) {
		tinput = THTensor_(newTranspose)(input, ndim - 1, ndim - 2);
		tgradOutput = THTensor_(newTranspose)(gradOutput, ndim - 1, ndim - 2);

		input = THTensor_(newContiguous)(tinput);
		gradOutput = THTensor_(newContiguous)(tgradOutput);
	} else {
		input = THTensor_(newContiguous)(input);
		gradOutput = THTensor_(newContiguous)(gradOutput);
	}

	THNN_(TemporalRowConvolution_shapeCheck)
	        (state, input, gradOutput, gradWeight, gradBias, kW, dW, padW);

	long inputFrameSize = gradWeight->size[0];
	long nInputFrame = input->size[ndim - 1];
	long nOutputFrame = (nInputFrame + 2 * padW - kW) / dW + 1;

	if (ndim == 2) {
		THNN_(TemporalRowConvolution_accGradParameters_frame)(
			gradOutput, gradWeight, gradBias, finput, scale);
	} else {
		long T = input->size[0];
		long t;

		for (t = 0; t < T; t++) {
			THTensor *gradOutput_t = THTensor_(newSelect)(gradOutput, 0, t);
			THTensor *finput_t = THTensor_(newSelect)(finput, 0, t);

			THNN_(TemporalRowConvolution_accGradParameters_frame)(
				gradOutput_t, gradWeight, gradBias, finput_t, scale);

			THTensor_(free)(gradOutput_t);
			THTensor_(free)(finput_t);
		}
	}

	if (!featFirst) {
		THTensor_(free)(tinput);
		THTensor_(free)(tgradOutput);
	}

	THTensor_(free)(input);
	THTensor_(free)(gradOutput);
}

#endif
