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_yixiao

铁虫 (小有名气)

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虫号: 843338
注册: 2009-09-08
专业: 钢铁冶金

[交流] 【求助】传热计算的OpenMP并行计算已有1人参与

请大家帮帮忙
在温度场的计算过程中，时间步长上的迭代过程是相互关联，相互影响的。一次迭代需要使用上一次迭代的运算结果，故迭代之间不宜实现并行化。而在一次迭代内部，温度场的计算仅需要前一次时刻的计算结果，各个计算过程之间没有影响，可以进行并行计算。但我进行以下的并行计算后结果同串行相差很大，且计算时间反而增加，不知道问题出在哪里。
以下即是我的并行程序，用到的OpenMP指令是section指令：
（其中，程序中的h_w_f，Water_Tem_in，Mould_dt，Mould_dy等为全局变量，AA、BB、C_mould，float Density_mould等为局部变量，q1，Q2,q3，Q4为调用函数。）
for(k=0;k<100;k++)
{

            for(i=0;i<=xx;i++)
            {
                     for(j=0;j<=yy;j++)
                     {
                              thermal_1[j]=thermal_0[j];
                     }
            }

#pragma omp parallel sections
            {
#pragma omp section
                     {

                              for(i=0;i<=xx;i++)
                              {
                                    for(j=0;j<=yA;j++)
                                    {
                              if (i==xK && j==0)//K
                              {
                                    thermal_0[j] = float(2*AA*thermal_1[i+1][j]+2*BB*thermal_1[j+1]+thermal_1[j]*(1-2*AA-2*BB)
                                             +2*h_w_f*(Water_Tem_in - thermal_1[j])*Mould_dt/(Mould_dy*C_mould*Density_mould));
                              }
                              else if (i==xJ && j==0)//J
                              {
                                    thermal_0[j] = float(2*AA*thermal_1[i-1][j]+2*BB*thermal_1[j+1]+thermal_1[j]*(1-2*AA-2*BB)
                                             +2*h_w_f*(Water_Tem_in - thermal_1[j])*Mould_dt/(Mould_dy*C_mould*Density_mould));
                              }

                              //////////[side]
                              else if ((i>=xK && i<=xJ) && j==0)//KJ
                              {
                                    thermal_0[j] = float(AA*(thermal_1[i-1][j]+thermal_1[i+1][j])+2*BB*(thermal_1[j+1])
                                             +thermal_1[j]*(1-2*AA-2*BB)
                                             +2*h_w_f*(Water_Tem_in - thermal_1[j])*Mould_dt/(Mould_dy*C_mould*Density_mould));
                              }
                              else if (i==xJ && (j>=0 && j<=yA))//JP
                              {
                                    thermal_0[j] = float(2*AA*(thermal_1[i-1][j])+BB*(thermal_1[j-1]+thermal_1[j+1])
                                             +thermal_1[j]*(1-2*AA-2*BB));
                              }
                              else if ((i>=xK && i<=xJ) && j==yA)//PL
                              {
                                    thermal_0[j] = float(AA*(thermal_1[i-1][j]+thermal_1[i+1][j])+2*BB*(thermal_1[j-1])
                                             +thermal_1[j]*(1-2*AA-2*BB)+2*Q4(i-xK)*Mould_dt/(Mould_dy*C_mould*Density_mould));
                              }
                              else if (i==xK && (j>=0 && j<=yA))//LK
                              {
                                    thermal_0[j] = float(2*AA*(thermal_1[i+1][j])+BB*(thermal_1[j-1]+thermal_1[j+1])+thermal_1[j]*(1-2*AA-2*BB));
                              }
                              else if ((i>=xK && i<=xJ) && (j<=yA) )// fix
                              {
                                    thermal_0[j] = float(AA*(thermal_1[i-1][j]+thermal_1[i+1][j])+BB*(thermal_1[j-1]+thermal_1[j+1])+thermal_1[j]*(1.0-2*AA-2*BB));
                              }

                                    }

                     }
            }

pragma omp section
                     {
                              for(i=0;i<=xx;i++)
                              {
                                    for(j=yB;j<=yy;j++)
                                    {
                              if (i==xJ && j==yy)//E
                              {
                                    thermal_0[j] = float(2*AA*thermal_1[i-1][j]+2*BB*thermal_1[j-1]+thermal_1[j]*(1-2*AA-2*BB)
                                             +2*h_w_l*(Water_Tem_in - thermal_1[j])*Mould_dt/(Mould_dy*C_mould*Density_mould));
                              }
                              else if (i==xK && j==yy)//D
                              {
                                    thermal_0[j] = float(2*AA*thermal_1[i+1][j]+2*BB*thermal_1[j-1]+thermal_1[j]*(1-2*AA-2*BB)
                                             +2*h_w_l*(Water_Tem_in - thermal_1[j])*Mould_dt/(Mould_dy*C_mould*Density_mould));
                              }

                              ////side
                              else if ((i>=xK && i<=xJ) && j==yB)//MN
                              {
                                    thermal_0[j] = float(AA*(thermal_1[i-1][j]+thermal_1[i+1][j])+2*BB*(thermal_1[j+1])
                                             +thermal_1[j]*(1-2*AA-2*BB)+2*Q2(i-xK)*Mould_dt/(Mould_dy*C_mould*Density_mould));
                              }
                              else if (i==xJ && (j>=yB && j<=yy))//NE
                              {
                                    thermal_0[j] = float(2*AA*(thermal_1[i-1][j])+BB*(thermal_1[j-1]+thermal_1[j+1])+thermal_1[j]*(1-2*AA-2*BB));
                              }
                              else if ((i>=xK && i<=xJ) && j==yy)//ED
                              {
                                    thermal_0[j] = float(AA*(thermal_1[i-1][j]+thermal_1[i+1][j])+2*BB*(thermal_1[j-1])+thermal_1[j]*(1-2*AA-2*BB)
                                             +2*h_w_l*(Water_Tem_in - thermal_1[j])*Mould_dt/(Mould_dy*C_mould*Density_mould));
                              }
                              else if (i==xK && (j>=yB && j<=yy))//DM
                              {
                                    thermal_0[j] = float(2*AA*(thermal_1[i+1][j])+BB*(thermal_1[j-1]+thermal_1[j+1])+thermal_1[j]*(1-2*AA-2*BB));
                              }

                              else if((i>=xK && i<=xJ) && (j>=yB))// loose
                              {
                                    thermal_0[j] = float(AA*(thermal_1[i-1][j]+thermal_1[i+1][j])+BB*(thermal_1[j-1]+thermal_1[j+1])+thermal_1[j]*(1.0-2*AA-2*BB));
                              }

                                    }
                              }
                     }

#pragma omp section
                     {
                              for(i=0;i<=xK;i++)
                              {
                                    for(j=yA;j<=yB;j++)
                                    {
                              if (i==0 && j==yA)//A
                              {
                                    thermal_0[j] = float(2*AA*thermal_1[i+1][j]+2*BB*thermal_1[j+1]+thermal_1[j]*(1-2*AA-2*BB)
                                             +2*h_n_l*(Water_Tem_in - thermal_1[j])*Mould_dt/(Mould_dx*C_mould*Density_mould));
                              }
                              else if (i==0 && j==yB)//B
                              {
                                    thermal_0[j] = float(2*AA*thermal_1[i+1][j]+2*BB*thermal_1[j-1]+thermal_1[j]*(1-2*AA-2*BB)
                                             +2*h_n_l*(Water_Tem_in - thermal_1[j])*Mould_dt/(Mould_dx*C_mould*Density_mould));
                              }
                              else if (i==xK && j==yA)//L
                              {
                                    thermal_0[j] = float(AA*(thermal_1[i-1][j]+thermal_1[i+1][j])+BB*(thermal_1[j-1]+thermal_1[j+1])+thermal_1[j]*(1-2*AA-2*BB)
                                             +Q4(i-xK)*Mould_dt/(Mould_dy*C_mould*Density_mould)+q1(j)*Mould_dt/(Mould_dx*C_mould*Density_mould));
                              }
                              else if (i==xK && j==yB)//M
                              {
                                    thermal_0[j] = float(AA*(thermal_1[i-1][j]+thermal_1[i+1][j])+BB*(thermal_1[j-1]+thermal_1[j+1])+thermal_1[j]*(1-2*AA-2*BB)
                                             +Q2(i-xK)*Mould_dt/(Mould_dy*C_mould*Density_mould)+q1(j)*Mould_dt/(Mould_dx*C_mould*Density_mould));
                              }
///side
                              else if ((i>=0 && i<=xK) && j==yA)//AL
                              {
                                    thermal_0[j] = float(AA*(thermal_1[i-1][j]+thermal_1[i+1][j])+2*BB*(thermal_1[j+1])+thermal_1[j]*(1-2*AA-2*BB));
                              }
                              else if (i==xK && (j>=yA && j<=yB))//LM
                              {
                                    thermal_0[j] = float(2*AA*(thermal_1[i-1][j])+BB*(thermal_1[j-1]+thermal_1[j+1])
                                             +thermal_1[j]*(1-2*AA-2*BB)+2*q1(j)*Mould_dt/(Mould_dx*C_mould*Density_mould));
                              }
                              else if ((i>=0 && i<=xK) && j==yB)//MB
                              {
                                    thermal_0[j] = float(AA*(thermal_1[i-1][j]+thermal_1[i+1][j])+2*BB*(thermal_1[j-1])+thermal_1[j]*(1-2*AA-2*BB));
                              }
                              else if (i==0 && (j>=yA && j<=yB))//BA
                              {
                                    thermal_0[j] = float(2*AA*(thermal_1[i+1][j])+BB*(thermal_1[j-1]+thermal_1[j+1])+thermal_1[j]*(1-2*AA-2*BB)
                                             +2*h_n_l*(Water_Tem_in - thermal_1[j])*Mould_dt/(Mould_dx*C_mould*Density_mould));
                              }

                              else if (i<=xK  && (j>=yA && j<=yB))// left
                              {
                                    thermal_0[j] = float(AA*(thermal_1[i-1][j]+thermal_1[i+1][j])+BB*(thermal_1[j-1]+thermal_1[j+1])+thermal_1[j]*(1.0-2*AA-2*BB));
                              }

                                    }
                              }
                     }

#pragma omp section
                     {
                              for(i=xJ;i<=xx;i++)
                              {
                                    for(j=yA;j<=yB;j++)
                                    {
                              if (i==xJ && j==yA)//P
                              {
                                    thermal_0[j] = float(AA*(thermal_1[i-1][j]+thermal_1[i+1][j])+BB*(thermal_1[j-1]+thermal_1[j+1])+thermal_1[j]*(1-2*AA-2*BB)
                                             +Q4(i-xK)*Mould_dt/(Mould_dy*C_mould*Density_mould)+q3(j)*Mould_dt/(Mould_dx*C_mould*Density_mould));
                              }
                              else if (i==xx && j==yA)//H
                              {
                                    thermal_0[j] = float(2*AA*thermal_1[i-1][j]+2*BB*thermal_1[j+1]+thermal_1[j]*(1-2*AA-2*BB)
                                             +2*h_n_r*(Water_Tem_in - thermal_1[j])*Mould_dt/(Mould_dx*C_mould*Density_mould));
                              }
                              else if (i==xJ && j==yB)//N
                              {
                                    thermal_0[j] = float(AA*(thermal_1[i-1][j]+thermal_1[i+1][j])+BB*(thermal_1[j-1]+thermal_1[j+1])+thermal_1[j]*(1-2*AA-2*BB)
                                             +Q2(i-xK)*Mould_dt/(Mould_dy*C_mould*Density_mould)+q3(j)*Mould_dt/(Mould_dx*C_mould*Density_mould));
                              }
                              else if (i==xx && j==yB)//G
                              {
                                    thermal_0[j] = float(2*AA*thermal_1[i-1][j]+2*BB*thermal_1[j-1]+thermal_1[j]*(1-2*AA-2*BB)
                                             +2*h_n_r*(Water_Tem_in - thermal_1[j])*Mould_dt/(Mould_dx*C_mould*Density_mould));
                              }
////side
                              else if ((i>=xJ && i<=xx) && j==yA)//PH
                              {
                                    thermal_0[j] = float(AA*(thermal_1[i-1][j]+thermal_1[i+1][j])+2*BB*(thermal_1[j+1])+thermal_1[j]*(1-2*AA-2*BB));
                              }
                              else if (i==xx && (j>=yA && j<=yB))//HG
                              {
                                    thermal_0[j] = float(2*AA*(thermal_1[i-1][j])+BB*(thermal_1[j-1]+thermal_1[j+1])
                                             +thermal_1[j]*(1-2*AA-2*BB)+2*h_n_r*(Water_Tem_in - thermal_1[j])*Mould_dt/(Mould_dx*C_mould*Density_mould));
                              }
                              else if ((i>=xJ && i<=xx) && j==yB)//GN
                              {
                                    thermal_0[j] = float(AA*(thermal_1[i-1][j]+thermal_1[i+1][j])+2*BB*(thermal_1[j-1])+thermal_1[j]*(1-2*AA-2*BB));
                              }
                              else if (i==xJ && (j>=yA && j<=yB))//NP
                              {
                                    thermal_0[j] = float(2*AA*(thermal_1[i+1][j])+BB*(thermal_1[j-1]+thermal_1[j+1])
                                             +thermal_1[j]*(1-2*AA-2*BB)+2*q3(j)*Mould_dt/(Mould_dx*C_mould*Density_mould));
                              }

                              else if ( i>=xJ && (j>=yA && j<=yB))// right
                              {
                                    thermal_0[j] = float(AA*(thermal_1[i-1][j]+thermal_1[i+1][j])+BB*(thermal_1[j-1]+thermal_1[j+1])+thermal_1[j]*(1.0-2*AA-2*BB));
                              }


                                    }
                              }

                     }

            }
}

本文来自: 小木虫论坛 http://muchong.com/bbs/viewthread.php?tid=2410411