Aggregate over multiple fact fields. Result looks like this: http://imgur.com/fI636rq The aggregator returns first field for renderers without multifield support. The renderer is a modified version of the built-in table to support multifield. Quick and dirty but it gets the job done. For https://github.com/nicolaskruchten/pivottable.

multifact_sum_aggregator.js

multifactSumAggregator = function() {
  return function(facts) {

    return function() {
      var summedFacts = {};

      for (_i = 0, _len = facts.length; _i < _len; _i++) {
        summedFacts[facts[_i]] = 0
      }

      return {

        push: function(record) {
          for ( _i = 0, _len = facts.length; _i < _len; _i++) {
            summedFacts[facts[_i]] += parseFloat(record[facts[_i]]);
          }
        },

        multivalue: function() {
          return summedFacts;
        },

        // return the first element for unsupported renderers.
        value: function() { return summedFacts[facts[0]]; },
        format: function(x) { return x; },

        label: "Facts"
      };
    };
  };
}	

multifact_table_renderer.js

multifactTableRenderer = function(){
  return function(pivotData) {
    var aggregator, c, colAttrs, colKey, colKeys, i, j, r, result, rowAttrs, rowKey, rowKeys, th, totalAggregator, tr, txt, val, x;
    colAttrs = pivotData.colAttrs;
    rowAttrs = pivotData.rowAttrs;
    rowKeys = pivotData.getRowKeys();
    colKeys = pivotData.getColKeys();

    result = $("<table class='table table-bordered pvtTable'>");

    for (j in colAttrs) {
      c = colAttrs[j];
      tr = $("<tr>");
      if (parseInt(j) === 0 && rowAttrs.length !== 0) {

        tr.append($("<th>").attr("colspan", rowAttrs.length).attr("rowspan", colAttrs.length));
      }

      tr.append($("<th class='pvtAxisLabel'>").text(c));


      tmpAggregator = pivotData.getAggregator([], []);
      if (tmpAggregator.multivalue) {
        col_colspan = Object.keys(tmpAggregator.multivalue()).length;
        col_rowspan = 1
      } else {
        col_colspan = 1
        col_rowspan = 2
      }

      for (i in colKeys) {
        colKey = colKeys[i];
        th = $("<th class='pvtColLabel'>").text(colKey[j]).attr("colspan", col_colspan);
        if (parseInt(j) === colAttrs.length - 1 && rowAttrs.length !== 0) {
          th.attr("rowspan", col_rowspan);
        }
        tr.append(th);
      }
      if (parseInt(j) === 0) {
        tr.append($("<th class='pvtTotalLabel'>").text("Totals").attr("colspan", col_colspan).attr("rowspan", col_rowspan));
      }
      result.append(tr);
    }
    if (rowAttrs.length !== 0) {
      tr = $("<tr>");
      for (i in rowAttrs) {
        r = rowAttrs[i];
        tr.append($("<th class='pvtAxisLabel'>").text(r));
      }

      tmpAggregator = pivotData.getAggregator([], []);
      if (tmpAggregator.multivalue) {
        if (colAttrs.length > 0) {
          th = $("<th>");
          tr.append(th);
        }

        val = tmpAggregator.multivalue();
        for (i in colKeys) {
          for (v in val) {
            tr.append($("<th class='pvtColLabel'>").text(v).data("value", v));
          }
        }

        for (v in val) {
          tr.append($("<th class='pvtColLabel'>").text(v).data("value", v));
        }
      } else {
        th = $("<th>");
        if (colAttrs.length === 0) {
          th.addClass("pvtTotalLabel").text("Totals");
        }
        tr.append(th);
      }

      result.append(tr);
    }
    for (i in rowKeys) {
      rowKey = rowKeys[i];
      tr = $("<tr>");
      for (j in rowKey) {
        txt = rowKey[j];
        th = $("<th class='pvtRowLabel'>").text(txt).attr("rowspan", x);
        if (parseInt(j) === rowAttrs.length - 1 && colAttrs.length !== 0) {
          th.attr("colspan", 2);
        }
        tr.append(th);
      }
      for (j in colKeys) {
        colKey = colKeys[j];
        aggregator = pivotData.getAggregator(rowKey, colKey);

        if (aggregator.multivalue) {
          val = aggregator.multivalue();
          for (v in val) {
            tr.append($("<td class='pvtVal row" + i + " col" + j + "'>").text(aggregator.format(val[v])).data("value", val[v]));
          }
        } else {
          val = aggregator.value();
          tr.append($("<td class='pvtVal row" + i + " col" + j + "'>").text(aggregator.format(val)).data("value", val));
        }

      }
      totalAggregator = pivotData.getAggregator(rowKey, []);


      if (totalAggregator.multivalue) {
        val = totalAggregator.multivalue();
        for (v in val) {
          tr.append($("<td class='pvtTotal rowTotal'>").text(totalAggregator.format(val[v])).data("value", val[v]).data("for", "row" + i));
        }
      } else {
        val = totalAggregator.value();
        tr.append($("<td class='pvtTotal rowTotal'>").text(totalAggregator.format(val)).data("value", val).data("for", "row" + i));
      }

      result.append(tr);
    }
    tr = $("<tr>");
    th = $("<th class='pvtTotalLabel'>").text("Totals");
    th.attr("colspan", rowAttrs.length + (colAttrs.length === 0 ? 0 : 1));
    tr.append(th);
    for (j in colKeys) {
      colKey = colKeys[j];
      totalAggregator = pivotData.getAggregator([], colKey);

      if (totalAggregator.multivalue) {
        val = totalAggregator.multivalue();
        for (v in val) {
          tr.append($("<td class='pvtTotal colTotal'>").text(totalAggregator.format(val[v])).data("value", val[v]).data("for", "col" + j));
        }
      } else {
        val = totalAggregator.value();
        tr.append($("<td class='pvtTotal colTotal'>").text(totalAggregator.format(val)).data("value", val).data("for", "col" + j));
      }
    }

    totalAggregator = pivotData.getAggregator([], []);

    if (totalAggregator.multivalue) {
      val = totalAggregator.multivalue();
      for (v in val) {
        tr.append($("<td class='pvtGrandTotal'>").text(totalAggregator.format(val[v])).data("value", val[v]));
      }
    } else {
      val = totalAggregator.value();
      tr.append($("<td class='pvtGrandTotal'>").text(totalAggregator.format(val)).data("value", val));
    }

    result.append(tr);
    result.data("dimensions", [rowKeys.length, colKeys.length]);
    return result;
  };
};

report.js

// Putting the pieces together.

var custom_renderers = {
	"Multifact Table": multifactTableRenderer()
};

var custom_aggregators = {
	"Multifact aggregator": multifactSumAggregator()
};


$("#declarations_report #pivottable").pivotUI(data, {
	aggregators: $.extend(custom_aggregators, $.pivotUtilities.aggregators),
	renderers: $.extend(custom_renderers, $.pivotUtilities.renderers, $.pivotUtilities.gchart_renderers),
	rows: ["person"],
	cols: ["company"],
	vals: ["hours", "turnover", "profit_margin"],
	hiddenAttributes: ["id"]
});

To fix the problem with colspan, you just need to change:

          val = aggregator.value();
          tr.append($("<td class='pvtVal row" + i + " col" + j + "'>").text(aggregator.format(val)).data("value", val));

to

val = aggregator.value();
          if (val) {
            tr.append($("<td class='pvtVal row" + i + " col" + j + "'>").text(aggregator.format(val)).data("value", val));
          }
          else {
            tmpAggregator = pivotData.getAggregator([], []);
            var cols_length = 1;
            if (tmpAggregator.multivalue) {
              cols_length = Object.keys(tmpAggregator.multivalue()).length;
            }
            for (var cl = 0; cl < cols_length; cl++) {
              tr.append($("<td class='pvtVal row" + i + " col" + j + "-" + cl + "'>").text("").data("value", null));
            }
          }

on line 99 of multifact_table_renderer.js

Is it right @zuk38 ?

Thanks for this solution.