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how can i transfer a variable's value from one function to another?

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Lin LI
Lin LI 2011-10-6
I want to transfer ther value of Protrusion(i) from function G_yi to function sumin, in other words, I want to use the value of Protrusion(i) in function sumin,like making it a global variable,but when i run the following code,it gave me a message"??? Error: File: sumin.m Line: 1 Column: 30 Unbalanced or misused parentheses or brackets.",I dont know why, if anyone can help, I will appreciate. below are one main code, and 3 function code.
Di=4e-3;
PR=double_int(0,Di,0,Di)
function SS=double_int(innlow,innhi,outlow,outhi)
Protrusion1=outlow;Protrusion2=outhi;Friction1=innlow;Friction2=innhi;
SS=quad(@G_yi,Protrusion1,Protrusion2,[],[],Friction1,Friction2);
function f=G_yi(Protrusion,Friction1,Friction2)
for i=1:n
f(i)=quad(@sumin,Friction1,Friction2,[],[],Protrusion(i));
end
f=f(:);
function fun=sumin(Friction,Protrusion(i))
MeanShearStress=5 ; %unit Pa
Density=1e3;
Ustar=sqrt(MeanShearStress/Density);
N=15;
D=zeros(N,1);
p=zeros(N,1);
for k=1:N-1;
D(1)=0.5e-3;
p(1)=1/N;
D(k+1)=D(k)+0.5e-3;
p(k+1)=p(k);
end;
%p1=1/3, p2=1/3,p3=1/3
%D1=40e-6,D2=60e-6, D3=80e-6
KinematicViscosity=1.004e-6;
D50=4e-3;
Roughness=2*D50;
RoughnessRenolds=Ustar*Roughness/KinematicViscosity;
if RoughnessRenolds>100
Intensity=Ustar*2.14;
Skewness=0.43;
Flatness=2.88;
else
Intensity=Ustar*(-0.187*log(RoughnessRenolds)+2.93);
Skewness=0.102*log(RoughnessRenolds);
Flatness=0.136*log(RoughnessRenolds)+2.30;
end
CoefficientC=-0.993*log(RoughnessRenolds)+12.36;
SpecificWeightofSand=1.8836e4;
SpecificWeightofWater=9.789e3 ;
Di=4e-3;
% Protrusion=1e-3;
Thickness=1.5*D50;
Y1=0.25*Thickness;
Y2(i)=0.25*Thickness+Protrusion(i);
Sum=zeros(N,1);
for m=1:N-1
Kapa=0.4;
ff1=@(y) (Ustar*CoefficientC.*y/Thickness).*sqrt((0.5*Di)^2-(y-Protrusion(i)-Y1+0.5*Di).^2);
ff2=@(y) sqrt((0.5*Di)^2-(y-Protrusion(i)-Y1+0.5*Di).^2);
if Y2(i)<=Thickness
MeanBedVelocity(i)=quad(ff1,Y1,Y2(i))./(quad(ff2,Y1,Y2(i)));
else
MeanBedVelocity(i)=(quad(ff1,Y1,Thickness)+quad(ff1,Thickness,Y2(i)))./(quad(ff2,Y1,Y2(i)));
end
if MeanBedVelocity(i)<=Ustar*CoefficientC
Yb(i)=(MeanBedVelocity(i)*Thickness)/(Ustar*CoefficientC);
else
Yb(i)=Thickness*exp(Kapa*(MeanBedVelocity(i)/Ustar-CoefficientC));
end;
ParticleRenolds(i)=MeanBedVelocity(i).*Protrusion(i)/KinematicViscosity;
if ParticleRenolds(i)<=1754
Cd(i)=(24./ParticleRenolds(i)).*(1+0.15*ParticleRenolds(i).^0.687);
else
Cd(i)=0.36;
end;
if ParticleRenolds(i)<8000
Cl(i)=Cd(i);
end;
h1(i)=Yb(i)-Y1-Protrusion(i)+0.5*Di;
h2=Di*(Friction+0.5*D(m)-0.5*Di)/(Di+D(m));
Ld(i)=h1(i)+h2;
Ll=sqrt((0.5*Di)^2-h2.^2);
Lw=Ll;
Pei=zeros(N,1);
Phi=zeros(N,1);
for j=2:N;
Pei(1)=p(1)*Di/(Di+D(1));
Pei(j)=p(j)*Di/(Di+D(j))+ Pei(j-1);
Phi(j)=1-Pei(j);
end;
HidingFactor=(Pei(N)/Phi(N))^0.6;
EffectiveShearStress=HidingFactor*MeanShearStress;
% SpecificWeightofSand=1.8836e4;
% SpecificWeightofWater=9.789e3 ; %at 20 degree centigrade
DimensionlessEffectiveShearStress= EffectiveShearStress/((SpecificWeightofSand-SpecificWeightofWater)*Di);
ff3=@(y) sqrt((0.5*Di)^2-(y-Protrusion(i)-Y1+0.5*Di).^2);
A(i)=quad(ff3,Y1,Y2(i));
Br=Ustar*sqrt((2*Lw*pi*Di^2)./((Cd(i).*Ld(i)+Cl(i).*Ll)*6.*A(i)*DimensionlessEffectiveShearStress)); % Rolling Threshold
Bl=Ustar*sqrt((2*pi*Di^2)/(Cl(i)*6.*A(i)*DimensionlessEffectiveShearStress)); %Lifting Threshold
%syms Ub ; % Instantaneous velocity
% U=((Ub-MeanBedVelocity)/Intensity);
PDF=@(Ub) (exp(-((Ub-MeanBedVelocity)/Intensity).^2/2)/(Intensity*sqrt(2*pi))).*(1+(Skewness/factorial(3))*(((Ub-MeanBedVelocity)/Intensity).^3-3*((Ub-MeanBedVelocity)/Intensity))+(Flatness-3)*(((Ub-MeanBedVelocity)/Intensity).^4-6*((Ub-MeanBedVelocity)/Intensity).^2+3)/factorial(4))/Intensity; %PDF of Velocity Fluctuation
Pr(i)=quad(PDF,-Bl,-Br)+quad(PDF,Br,Bl);
% Pl=1-quad(PDF,-Bl,Bl);
%end
Sum(1)=p(1)*Pr(i);
Sum(m+1)=p(m)*Pr(i)+Sum(m);
end;
fun=Sum(m+1);

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采纳的回答

William
William 2011-10-6
Two methods I use:
1. Use global variables (be careful) use all caps for a variable
global NEW_VARAIBLE;
Or use a "save" command to save data somewhere on your drive and then acess it by using the "load" command
save mydata.mat
load mydata.mat

更多回答（1 个）

Walter Roberson
Walter Roberson 2011-10-6
function fun=sumin(Friction,Protrusion(i))
is illegal syntax. The variables on the right hand side of a function declaration must be pure variable names with no indexing, no list construction, no cell referencing, no structure array referencing.
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