Class: RedShift::DerivativeFlow

Inherits:
Flow show all
Defined in:
lib/redshift/component.rb,
lib/redshift/target/c/flow/derivative.rb

Constant Summary

Constants inherited from Flow

Flow::CT_STRUCT_NAME

Instance Attribute Summary collapse

Attributes inherited from Flow

#formula, #strict, #var

Instance Method Summary collapse

Methods inherited from Flow

#external_constant?, #make_ct_struct, #translate, #translate_link

Constructor Details

#initialize(v, f, feedback) ⇒ DerivativeFlow

Returns a new instance of DerivativeFlow.



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# File 'lib/redshift/component.rb', line 108

def initialize v, f, feedback
  super(v, f)
  @feedback = feedback
end

Instance Attribute Details

#feedback ⇒ Object (readonly)

Returns the value of attribute feedback.



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# File 'lib/redshift/component.rb', line 107

def feedback
  @feedback
end

Instance Method Details

#flow_wrapper(cl, state) ⇒ Object 



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# File 'lib/redshift/target/c/flow/derivative.rb', line 2

def flow_wrapper cl, state
  var_name = @var
  flow = self
  flow_name = "flow_#{CGenerator.make_c_name cl.name}_#{var_name}_#{state}"
  feedback = @feedback
  
  Component::FlowWrapper.make_subclass flow_name do
    @inspect_str = "#{cl.name}:#{state}: #{var_name} = #{flow.formula}'"

    ssn = cl.shadow_struct.name
    cont_state_ssn = cl.cont_state_class.shadow_struct.name
    
    # We need the struct
    shadow_library_source_file.include(cl.shadow_library_include_file)
    
    init_rhs_name  = "#{var_name}_init_rhs"
    cl.class_eval do
      shadow_attr_accessor init_rhs_name => "double #{init_rhs_name}"
    end
    
    shadow_library_source_file.define(flow_name).instance_eval do
      arguments "ComponentShadow *comp_shdw"
      declare :shadow => %{
        struct #{ssn} *shadow;
        struct #{cont_state_ssn} *cont_state;
        ContVar  *var;
        double    antiddt, *scratch;
        double    time_step;
      }
      setup :shadow => %{
        shadow = (#{ssn} *)comp_shdw;
        cont_state = (#{cont_state_ssn} *)shadow->cont_state;
        var = &cont_state->#{var_name};
        scratch = &shadow->#{init_rhs_name};
        time_step = shadow->world->time_step;
      }
      setup :rk_level => %{
        shadow->world->rk_level--;
      } # has to happen before referenced alg flows are called in other setups
      if feedback ## possible to unite these cases somehow?
        body %{
          switch (shadow->world->rk_level) {
          case 0:
            #{flow.translate(self, "antiddt", 0, cl).join("
            ")};
            var->value_0 = var->value_1 =
            var->value_2 = var->value_3 =
            (antiddt - *scratch) / time_step;
            *scratch = antiddt;
          }
          shadow->world->rk_level++;
          var->rk_level = shadow->world->rk_level;
        }
      else
        body %{
          switch (shadow->world->rk_level) {
          case 0:
            #{flow.translate(self, "antiddt", 0, cl).join("
            ")};
            var->value_1 = var->value_0;
            *scratch = antiddt;
            break;

          case 1:
            #{flow.translate(self, "antiddt", 1, cl).join("
            ")};
            var->value_2 = (antiddt - *scratch) / (time_step/2);
            *scratch = antiddt;
            break;

          case 2:
            #{flow.translate(self, "antiddt", 2, cl).join("
            ")};
            var->value_3 = (antiddt - *scratch) / (time_step/2);
            break;

          case 3:
            #{flow.translate(self, "antiddt", 3, cl).join("
            ")};
            var->value_0 = (antiddt - *scratch) / (time_step/2);
            break;

          default:
            rb_raise(#{declare_class RuntimeError},
              "Bad rk_level, %d!", shadow->world->rk_level);
          }

          shadow->world->rk_level++;
          var->rk_level = shadow->world->rk_level;
        }
      end
    end

    define_c_method :calc_function_pointer do
      body "shadow->flow = &#{flow_name}"
    end
  end
end