forward
==============

.. js:function:: MaxPoolingLayer.forward() 

    順伝播

ソース
^^^^^^

.. code-block:: js

            forward() {
                var lap = new Lap(this.forwardTime);
    
                var prev_layer = this.prevLayer;
    
                var prev_y_dt = prev_layer.y_.dt;
    
                // 出力先
                var output_idx = 0;
    
                // バッチ内のデータに対し
                for (var batch_idx = 0; batch_idx < miniBatchSize; batch_idx++) {
    
                    // すべての特徴マップに対し
                    for (var channel_idx = 0; channel_idx < this.numChannels; channel_idx++) {
    
                        // 出力の行に対し
                        for (var r1 = 0; r1 < this.numRows; r1++) {
                            var r0 = r1 * this.filterSize;
    
                            // 出力の列に対し
                            for (var c1 = 0; c1 < this.numCols; c1++) {
                                var c0 = c1 * this.filterSize;
    
                                if(inGradientCheck){
    
                                    var r2 = this.maxRow[output_idx];
                                    var c2 = this.maxCol[output_idx];
                                    var prev_y_idx = batch_idx * prev_layer.unitSize + (channel_idx * prev_layer.numRows + (r0 + r2)) * prev_layer.numCols + (c0 + c2);
                                    this.y_.dt[output_idx] = prev_y_dt[prev_y_idx];
                                }
                                else{
    
                                    var max_val = -10000;
                                    var max_row, max_col;
    
                                    // フィルターの行に対し
                                    for (var r2 = 0; r2 < this.filterSize; r2++) {
    
                                        // フィルターの列に対し
                                        for (var c2 = 0; c2 < this.filterSize; c2++) {
    
                                            var prev_y_idx = batch_idx * prev_layer.unitSize + (channel_idx * prev_layer.numRows + (r0 + r2)) * prev_layer.numCols + (c0 + c2);
                                            var val = prev_y_dt[prev_y_idx];
                                            if (max_val < val) {
    
                                                max_val = val;
                                                max_row = r2;
                                                max_col = c2;
                                            }
                                        }
                                    }
    
                                    this.y_.dt[output_idx] = max_val;
                                    this.maxRow[output_idx] = max_row;
                                    this.maxCol[output_idx] = max_col;
                                }
    
                                output_idx++;
                            }
                        }
                    }
                }
    
                Assert(output_idx == this.y_.dt.length);
                lap.Time();
            }