While running this program I got the error "Error using mesh (line 71) Data dimensions must agree"

f=1000;
s=300;
theta= 45;
dp=0.000005;
rb=35;
Rt=20;
Rmj=18;
Rmn=9;
v1=0.4999;
v2=0.05;
E1=50;
E2=137000;
t=0:0.1:30*pi;
D=((1-v1^2)/E1)+((1-v2^2)/E2);
A=(1/Rt)+(1/Rmj);
B=(1/Rt)+(1/Rmn);
RE=((A*B)*((A+B)/2))^(-1/3);
k=1.0339*(B/A)^0.636;
e=1.003+0.5968*(A/B);
a=((3*e*f*RE*D*k^2)/pi)^(1/3);
b=((3*e*f*RE*D)/pi*k)^(1/3);
pm=1/pi.*((6*f*(1/D)^2)/RE)^(1/3);
x=1:1:10;
y=1:1:10;
[x,y]=meshgrid(x,y);
Pr=pm*sqrt(1-(x/a).^2-(y/b).^2);
Pr=abs(Pr)
v=(pi*s/30)*sqrt((y.*cot(theta)-(rb-dp)).^2*(sin(theta))^2+(x.^2*(cos(theta))^2));
[v,Pr]=meshgrid(v,Pr);
mrr=v.*Pr;
mesh(x,y,mrr)

Answer 1

[Walter Roberson]

f=1000;
s=300;
theta= 45;
dp=0.000005;
rb=35;
Rt=20;
Rmj=18;
Rmn=9;
v1=0.4999;
v2=0.05;
E1=50;
E2=137000;
t=0:0.1:30*pi;
D=((1-v1^2)/E1)+((1-v2^2)/E2);
A=(1/Rt)+(1/Rmj);
B=(1/Rt)+(1/Rmn);
RE=((A*B)*((A+B)/2))^(-1/3);
k=1.0339*(B/A)^0.636;
e=1.003+0.5968*(A/B);
a=((3*e*f*RE*D*k^2)/pi)^(1/3);
b=((3*e*f*RE*D)/pi*k)^(1/3);
pm=1/pi.*((6*f*(1/D)^2)/RE)^(1/3);
x=1:1:10;
y=1:1:10;
[x,y]=meshgrid(x,y);
Pr=pm*sqrt(1-(x/a).^2-(y/b).^2);
Pr=abs(Pr);
size(Pr)

ans = 1×2

10 10

v=(pi*s/30)*sqrt((y.*cot(theta)-(rb-dp)).^2*(sin(theta))^2+(x.^2*(cos(theta))^2));
[v,Pr]=meshgrid(v,Pr);
mrr=v.*Pr;
size(x), size(y), size(mrr), size(Pr)

ans = 1×2

10 10

ans = 1×2

10 10

ans = 1×2

100 100

ans = 1×2

100 100

mesh(x,y,mrr)

Error using mesh (line 71)
Data dimensions must agree.

Why are you taking an existing 10 x 10 array, Pr, and using it in meshgrid() to create a 100 x 100 array?

What output size are you expecting?

I would point out that when you assign a variable to have a different purpose, and it is not just a simple loop control variable, then you confuse people trying to read your code. I would therefore recommend that if your Pr is input to meshgrid() that your output should be some other variable name.