.. _program_listing_file_src_common_scheduling_parameter.h:

Program Listing for File scheduling_parameter.h
===============================================

|exhale_lsh| :ref:`Return to documentation for file <file_src_common_scheduling_parameter.h>` (``src/common/scheduling_parameter.h``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   #pragma once
   
   #include "common/logging.h"
   #include "common/utils.h"
   
   #include <string>
   
   namespace marian {
   
   // support for scheduling parameters that can be expressed with a unit, such as --lr-decay-inv-sqrt
   enum class SchedulingUnit {
     trgLabels, // "t": number of target labels seen so far
     updates,   // "u": number of updates so far (batches)
     epochs     // "e": number of epochs begun so far (very first epoch is 1)
   };
   
   struct SchedulingParameter {
     size_t n{0};                                  // number of steps measured in 'unit'
     SchedulingUnit unit{SchedulingUnit::updates}; // unit of value
   
     // parses scheduling parameters of the form NU where N=unsigned int and U=unit
     // Examples of valid inputs: "16000u" (16000 updates), "32000000t" (32 million target labels),
     // "100e" (100 epochs).
     static SchedulingParameter parse(std::string param) {
       SchedulingParameter res;
       if(!param.empty() && param.back() >= 'a') {
         switch(param.back()) {
           case 't': res.unit = SchedulingUnit::trgLabels; break;
           case 'u': res.unit = SchedulingUnit::updates;   break;
           case 'e': res.unit = SchedulingUnit::epochs;    break;
           default: ABORT("invalid unit '{}' in {}", param.back(), param);
         }
         param.pop_back();
       }
       double number = utils::parseNumber(param);
       res.n = (size_t)number;
       ABORT_IF(number != (double)res.n, "Scheduling parameters must be whole numbers"); // @TODO: do they?
       return res;
     }
   
     operator bool() const { return n > 0; } // check whether it is specified
   
     operator std::string() const { // convert back for storing in config
       switch(unit) {
         case SchedulingUnit::trgLabels: return std::to_string(n) + "t";
         case SchedulingUnit::updates  : return std::to_string(n) + "u";
         case SchedulingUnit::epochs   : return std::to_string(n) + "e";
         default: ABORT("corrupt enum value for scheduling unit");
       }
     }
   };
   
   }