How to use the yarn.app.mapreduce.am.resource.mb function in yarn

getDefaults: function (localDB) {
    this._super();
    this.getClusterData(localDB);
    var configs = {};
    jQuery.extend(configs, this.get('configsTemplate'));
    if (!this.clusterDataIsValid()) {
      return configs;
    }
    configs['yarn.nodemanager.resource.memory-mb'] = Math.round(this.get('containers') * this.get('ramPerContainer'));
    configs['yarn.scheduler.minimum-allocation-mb'] = Math.round(this.get('ramPerContainer'));
    configs['yarn.scheduler.maximum-allocation-mb'] = Math.round(this.get('containers') * this.get('ramPerContainer'));
    configs['yarn.app.mapreduce.am.resource.mb'] = Math.round(this.get('amMemory'));
    configs['yarn.app.mapreduce.am.command-opts'] = "-Xmx" + Math.round(0.8 * this.get('amMemory')) + "m";
    configs['mapreduce.map.memory.mb'] = Math.round(this.get('mapMemory'));
    configs['mapreduce.reduce.memory.mb'] = Math.round(this.get('reduceMemory'));
    configs['mapreduce.map.java.opts'] = "-Xmx" + Math.round(0.8 * this.get('mapMemory')) + "m";
    configs['mapreduce.reduce.java.opts'] = "-Xmx" + Math.round(0.8 * this.get('reduceMemory')) + "m";
    configs['mapreduce.task.io.sort.mb'] = Math.round(0.4 * this.get('mapMemory'));
    return configs;
  },

getDefaults: function (localDB) {
    this._super();
    this.getClusterData(localDB);
    var configs = {};
    jQuery.extend(configs, this.get('configsTemplate'));
    if (!this.clusterDataIsValid()) {
      return configs;
    }
    configs['yarn.nodemanager.resource.memory-mb'] = Math.round(this.get('containers') * this.get('ramPerContainer'));
    configs['yarn.scheduler.minimum-allocation-mb'] = Math.floor(this.get('ramPerContainer'));
    configs['yarn.scheduler.maximum-allocation-mb'] = Math.round(this.get('containers') * this.get('ramPerContainer'));
    configs['yarn.app.mapreduce.am.resource.mb'] = Math.floor(this.get('amMemory'));
    configs['yarn.app.mapreduce.am.command-opts'] = "-Xmx" + Math.round(0.8 * this.get('amMemory')) + "m";
    configs['mapreduce.map.memory.mb'] = Math.floor(this.get('mapMemory'));
    configs['mapreduce.reduce.memory.mb'] = Math.floor(this.get('reduceMemory'));
    configs['mapreduce.map.java.opts'] = "-Xmx" + Math.round(0.8 * this.get('mapMemory')) + "m";
    configs['mapreduce.reduce.java.opts'] = "-Xmx" + Math.round(0.8 * this.get('reduceMemory')) + "m";
    configs['mapreduce.task.io.sort.mb'] = Math.round(Math.min(0.4 * this.get('mapMemory'), 1024));
    return configs;
  },