For loope small increments

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marvin corado
marvin corado 2011-3-11
I cannot seem to find the solution to this problem. I write a for loop and i tell it to increment by a small value, but instead of starting at 1, it starts at 2.9110 here is the loop
for m=1:.001:4
m
end
does anyone know what its going on? i expect it to start at 1 and increment by .001 every time so that it goes 1.001, 1.002, 1.003 and so on thank you

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采纳的回答

Matt Fig
Matt Fig 2011-3-11
I don't know why you think this starts at 2.910. Perhaps you are running into the limit of your command window when trying to scroll back up after running the loop. Do this:
for m=1:.001:4
m
pause(.5)
end
Now you should see m incrementing like you expect as it prints slowly out.
  2 个评论
Paulo Silva
Paulo Silva 2011-3-11
Matt that code might freak out someone who doesn't know how to stop it (CTRL+C in MSWIN OS)
Matt Fig
Matt Fig 2011-3-11
True, but I thought everyone know about ctrl+c!

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更多回答（4 个）

Paulo Silva
Paulo Silva 2011-3-11
It works fine here, try this
m=1:.001:4;
What's the first value of the vector m?
marvin corado
marvin corado 2011-3-11
yes matt you are right, since the answer was printed in the command window and it always started at 2.910, but when i add the puase it starts at 1 and increments as i expect. thankfully i did know about ctrl_c :)
marvin corado
marvin corado 2011-3-11
ok but my problem seems to be something else then because my code is supposed to increment M starting at 2 and increment it .0001 up to 3. here is my code
f=0.006;
M= 3;
gamma = 1.4;
L_D=50;
Mx=1;
tol=1e2;
for Mx=2:.0001:3
a =(1-(M^2))/(gamma*M^2);
b = (gamma+1)/(2*gamma);
c = ((gamma+1)*(M^2))/(2+((gamma-1)*M^2));
%friction parameter coefficient for m1
Fp1 = a+(b*log(c));
%guessing
%friction parameter coefficient for guess
a1 =(1-(Mx^2))/(gamma*Mx^2);
b1 = (gamma+1)/(2*gamma);
c1 = ((gamma+1)*(Mx^2))/(2+((gamma-1)*Mx^2));
Fpx = a1+(b1*log(c1));
%Lx = L1star-Lxstar
Fpg=Fp1-Fpx;
%doing table A2 Normal shock
num=1+(((gamma-1)/2)*Mx^2);
den= (gamma*Mx^2)-((gamma-1)/2);
my= sqrt(num/den);
%friction parameter coefficient normal shock
a2 =(1-(my^2))/(gamma*my^2);
b2 = (gamma+1)/(2*gamma);
c2 = ((gamma+1)*(my^2))/(2+((gamma-1)*my^2));
Fpy = a2+(b2*log(c2));
%checking Lx+Ly* = L
X1=Fpg+Fpy;
R=4*f*L_D;
end
if abs(X1-R)<tol
z=Fpy
a=Fpg
a1=a/(4*f)
end
break
but that if statement does not happen for 2:.0001:3 but it happens for 2.5:.0001:3 do you guys know what is going on? thank you
  1 个评论
Matt Fig
Matt Fig 2011-3-11
Please select a best answer for this question, then start a new one. That way people can search Answers for a specific issue they are having.

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marvin corado
marvin corado 2011-3-11
should i start a new one? with my question above?

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