runtime error: Matrix is singular to working precision. results should be in numbers but coming as NaN

Question

Sat m 2013-3-18

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/67698-runtime-error-matrix-is-singular-to-working-precision-results-should-be-in-numbers-but-coming-as-n

i have generated an equation. it is not giving any compiling error. when i run it, it should be giving results in number. instead it is giving results in NaN. please let me know how to solve this problem

this is the code

   vy1=vy(1);
   disp(vy1);
   vy2=vy(2);
   disp(vy2);
   vy3=vy(3);
   disp(vy3);
   vy4=vy(4);
   disp(vy4);
   vy5=vy(5);
   disp(vy5);
   vy6=vy(6);
   disp(vy6);
   vy7=vy(7);
   disp(vy7);
   vy8=vy(8);
  disp(vy8);
  %assigning values of vy1...vy8 to actual extrinsic and intrinsic parameters
  ry21 = vy1;
  ry22 = vy2;
  ry23 = vy3;
  Tyy = vy4;
  ary11 = vy5;
  ary12 = vy6;
  ary13 = vy7;
  aTxy = vy8;
  %generating the gamma function from the simulated data 
  gy = sqrt(vy1^2+vy2^2+vy3^2);
  disp(gy);
  %generating aspect ratio from the simulated data 
  ay = (sqrt(vy5^2+vy6^2+vy7^2)/gy);
  disp(ay);
  %generating elements of rotation vector from the simulated data 
  ry11 = vy5/ay;
  ry12 = vy6/ay;
  ry13 = vy7/ay;
  Txy = vy8/ay;
R1y = [ry11,ry12,ry13];
R2y = [ry21,ry22,ry23];
R3y = cross(R1y,R2y);%generating R3 as R3 is the cross product of R1 amd R2 or R3=R1xR2
disp(R3y);
ry31 = R3y(1);
ry32 = R3y(2);
ry33 = R3y(3);
%generating 1st extrinsic parameter R or the rotation matrix from the
%simulated data 
Ry = [R1y;R2y;R3y];
disp(Ry);
%now we need to find another extrinsic parameter T from the simulated data 
%x1 = fx*(r11*X1+r12*Y1+r13*Z1+Tx)/(r31*X1+r32*Y1+r33*Z1+Tz);
%x1*Tz + fx*(r11*X1+r12*Y1+r13*Z1+Tx) = -x1(r31*X1+r32*Y1+r33*Z1)
% and 
%x2 = fx*(r11*X2+r12*Y2+r13*Z2+Tx)/(r31*X2+r32*Y2+r33*Z2+Tz);
%here x22 = x2
%x2*Tz + fx*(r11*X2+r12*Y2+r13*Z2+Tx) = -x2(r31*X2+r32*Y2+r33*Z2)
%in this case
for h=1:32
A1y = [xhk,(ry11*Xhk+ry12*Yhk+ry13*Zhk+Txy);];
disp(A1y);
end
for h=1:32
B1y = (-xhk*(ry31*Xhk+ry32*Yhk+ry33*Zhk));
disp(B1y);
end
%A1[Tz,fx] = B1;
%[Tz,fx]=(A1t*A1)-1*(A1t.B1)
J = transpose(A1y);
Py = J*A1y;
Qy = J*B1y;
Wy = Py\Qy;
disp(Wy);
break 
Tzy = Wy(1);
disp(Tzy);%we can get the 3rd parameter of extrinsic parameter Ty from the simulated data 
fxy = Wy(2);%effective focal length at x direction 
disp(fxy);
fyy = ay/fxy;%effective focal length at x direction
disp(fyy);
fY = sqrt(fxy^2+fyy^2);%intrinsic parameter f from the simulated data
disp(fY);%here we got the focal length calulated from the simulated data 
Ty = [Txy,Tyy,Tzy];%extrinsic parameter T from the simulated data 
disp(Ty);

the error is showing at this line

Wy = Py\Qy;

2 个评论
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Walter Roberson 2013-3-18

Perhaps you could show us Py and Qy ?

Sat m 2013-3-18

在 MATLAB Online 中打开

Py=transpose(A1y)*(A1y)
Qy=transpose(A1y)*(B1y)

where A1y and B1y is

for h=1:32
A1y = [xhk,(ry11*Xhk+ry12*Yhk+ry13*Zhk+Txy);];
disp(A1y);
end
for h=1:32
B1y = (-xhk*(ry31*Xhk+ry32*Yhk+ry33*Zhk));
disp(B1y);
end

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Answer 1

Walter Roberson 2013-3-18

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/67698-runtime-error-matrix-is-singular-to-working-precision-results-should-be-in-numbers-but-coming-as-n#answer_79139

在 MATLAB Online 中打开

Your code

for h=1:32
  A1y = [xhk,(ry11*Xhk+ry12*Yhk+ry13*Zhk+Txy);];
  disp(A1y);
end

overwrites A1y completely on each iteration through the loop, but it does so with values that are independent of "h".

If you are trying to use x1k, Y1k and so on, then you cannot do that using that kind of code.

http://matlab.wikia.com/wiki/FAQ#How_can_I_create_variables_A1.2C_A2.2C....2CA10_in_a_loop.3F

5 个评论
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Sat m 2013-3-18

在 MATLAB Online 中打开

i tried to do this assigning with arrays like

   X1(h)=xvals(1)
  disp(X1(h));

but it is showing error at disp() area

Walter Roberson 2013-3-18

在 MATLAB Online 中打开

Xh1 = xvals(1:32);
Yh1 = yvals(1:32);
Zh1 = zvals(1:32);
xh1 = fa * Xh1 ./ Zh1;    %but what if the z is 0?
yh1 = fa * Yh1 ./ Zh1;    %but what if the z is 0?

You did not show how you created xhk

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