iteration in the loop but the result doesn't change ; help

Hey every one :)

I have a small problem with my script .

I change the pression_max and V(j) for each iteration but the I have the same U in the end

Any one can help me please

Thanks

*****************************************************************

cte_Rdg_standard=0.011
cte_Rdg_premium=0.008
pression_max=[2 3 6 10 15 23 30 50 75 100 300 450 750 800]
Q_RPT_Span=100
V=[0.15*Q_RPT_Span , 0.3*Q_RPT_Span, 0.5*Q_RPT_Span , Q_RPT_Span]; % vecteur util lors de l'utilisation des Q_RPT Premium
Gauge_23=23;
Gauge_50=50;
Gauge_500=500;
Gauge_1000=1000;
U=ones(length(pression_max),1);
Up=ones(length(pression_max),1);
Matrice_0=ones(length(pression_max),length(V))
for j=1:1:length(V)
  for k=1:1:length(pression_max)
      if  pression_max(k)<=23
          Q_RPT_Span=Gauge_23;
          Pressure=pression_max(k);
          %V=[0.15*Q_RPT_Span , 0.3*Q_RPT_Span, 0.5*Q_RPT_Span , Q_RPT_Span];
          Q_RPT_AutoRanged_Span=V(j) ;
          if Q_RPT_AutoRanged_Span==Q_RPT_Span
              for i=1:1:length(Pressure)
                  if (0.3*Q_RPT_Span <= Pressure(i)) && (Pressure(i) <= Q_RPT_Span)
                      Up(i)=(cte_Rdg_premium/100).*Pressure(i);
                  else
                      Up(i)=0.3*(cte_Rdg_premium/100).*Q_RPT_Span;
                  end
              end
          end
          if (0.3*Q_RPT_Span < Q_RPT_AutoRanged_Span) && (Q_RPT_AutoRanged_Span < Q_RPT_Span)
              for i=1:1:length(Pressure)
                  if (0.3*Q_RPT_AutoRanged_Span <= Pressure(i)) && (Pressure(i) <= Q_RPT_Span)
                      Up(i)=(cte_Rdg_premium/100).*Pressure(i);
                  else
                      Up(i)=0.3*(cte_Rdg_premium/100).*Q_RPT_AutoRanged_Span;
                  end
              end
          end
          if Q_RPT_AutoRanged_Span<=0.3*Q_RPT_Span
              for i=1:1:length(Pressure)
                  if (0.09*Q_RPT_Span <= Pressure(i))% && (Pressure(i) <= Q_RPT_AutoRanged_Span)
                      Up(i)=(cte_Rdg_premium/100).*Pressure(i);
                  else
                      Up(i)=0.09*(cte_Rdg_premium/100).*Q_RPT_Span;
                  end
              end
          end
          U(k)=Up(i);
          U;
      end
      if  pression_max(k)>23 && pression_max(k) <= 50
          Q_RPT_Span=Gauge_50;
          if (0.3*Q_RPT_Span <= pression_max(k)) && (pression_max(k) <= Q_RPT_Span)
              U(k)=(cte_Rdg_standard/100).*pression_max(k);
          else
              U(k)=0.3*(cte_Rdg_standard/100).*Q_RPT_Span;
          end
      end
      if  pression_max(k)>50 && pression_max(k) <= 500
          Q_RPT_Span=Gauge_500;
          if (0.3*Q_RPT_Span <= pression_max(k)) && (pression_max(k) <= Q_RPT_Span)
              U(k)=(cte_Rdg_standard/100).*pression_max(k);
          else
              U(k)=0.3*(cte_Rdg_standard/100).*Q_RPT_Span;
          end
      end
      if  pression_max(k)>500 && pression_max(k) <= 1015
          Q_RPT_Span=Gauge_1000;
          if (0.3*Q_RPT_Span <= pression_max(k)) && (pression_max(k) <= Q_RPT_Span)
              U(k)=(cte_Rdg_standard/100).*pression_max(k);
          else
              U(k)=0.3*(cte_Rdg_standard/100).*Q_RPT_Span;
          end
      end
  end
  U;
  Matrice_0(:,j)=U;
end

Answer 1

[Walter Roberson]

You assign

Pressure=pression_max(k);

so Pressure is going to be a scalar. But then later in multiple places you loop over the elements of Pressure. It is legal to loop over the elements of a scalar, but it tends to suggest that the author of the code may have been confused over the meaning of the variable Pressure.

At the end of that group of loops you have

U(k)=Up(i);

outside of all of the "for i" loops. That is going to rely on the last value that "i" happened to have. Which would be 1. It does work out, but it is confusing. If there is the possibility of Pressure being more than one element long then are you sure that you want to store the last such result?

Using array indexing for scalars that must be scalars is legal but is going to lead to people like me asking "Is the reason you always get the same U because you are confused about the length of what you are processing?"