Shortening nested If statements

HI Friends,

I am trying to shorten this nested if statement, is there a way to make it more compact ?

GR = [3.78 2.06 1.58 1.21 0.82]
for i=1:x 
  ig(i) = 3.78;
  N(i) = Vel_mps(i)*io*ig(i)*60/pi/Dt;
  % Gear change with speed exceeding 2000 rpm
  if N(i) > Nopt
      ig(i) = 2.06;
      N(i) = Vel_mps(i)*io*ig(i)*60/pi/Dt;
      if N(i) > Nopt
          ig(i) = 1.58;
          N(i) = Vel_mps(i)*io*ig(i)*60/pi/Dt;
          if N(i) > Nopt
              ig(i) = 1.21;
              N(i) = Vel_mps(i)*io*ig(i)*60/pi/Dt;
              if N(i) > Nopt
                  ig(i) = 0.82;
                  N(i) = Vel_mps(i)*io*ig(i)*60/pi/Dt;
              end
          end
      end
  end
end

Answer 1

[Jeff Miller]

Approximately:

GR = [3.78 2.06 1.58 1.21 0.82];
magic_constants = [3.78 2.06 1.58 1.21 0.82];
for i=1:x 
    j = 0;
    Less = false;
    while ~Less & (j<numel(magic_constants)
       j = j + 1;
       ig(i) = magic_constants(j);
       N(i) = Vel_mps(i)*io*ig(i)*60/pi/Dt;
       Less = N(i) <= Nopt;
    end;
end;

[DIP]

Thank you Jeff..what is magic_constants?

[Jeff Miller]

Just an arbitrary name for an array to store your different ig values, initialized at the top. I wasn't sure what to call them, since I'm not sure what they reflect.

[DIP]

Thank you Jeff.

[Jan]

This code can be written with a FOR loop also:

GR = [3.78 2.06 1.58 1.21 0.82];
n  = numel(GR);
for i = 1:x
  c = Vel_mps(i) * io * 60 / pi / Dt;
  for j = 1:n
    d = GR(j) * c;
    if d > Nopt
      N(i)  = d;
      ig(i) = GR(j);
      break;  % Break: for j
    end
  end
end

And with FIND:

GR    = [3.78 2.06 1.58 1.21 0.82];
NoptX = Nopt / (io * 60 / pi / Dt);
for i = 1:x
  d     = Vel_mps(i) * GR;
  j     = find(d > NoptX, 1);
  N(i)  = d(j);
  ig(i) = GR(j);
end