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loudspeaker_driver example error?
Posted Nov 30, 2010, 6:23 a.m. EST 2 Replies
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Hi, folks,
I tried the loudspeaker_driver example, I right click on the study1->compute...it began to calculate and then give me an error:
Attempt to evaluate negative power of zero.
- Function: ^
Failed to evaluate temporary symbolic derivative variable.
- Variable: mod1.mf.murzz@VDN${if@7}
- Defined as: ((((mod1.mf.Bz*2)*(((((mod1.mf.Bphi^2)+(mod1.mf.Br^2))+(mod1.mf.Bz^2))^(-0.5))*0.5))*(1/unit_T_cf))*dmod1.mat2.def.MUR_dx1((sqrt((((mod1.mf.Bphi^2)+(mod1.mf.Br^2))+(mod1.mf.Bz^2)))/unit_T_cf)))
Failed to evaluate temporary symbolic derivative variable.
- Variable: mod1.mf.murinvzz@VDN${if@7}
- Defined as: (((-1)/(mod1.mf.murzz^2))*(((((mod1.mf.Bz*2)*(((((mod1.mf.Bphi^2)+(mod1.mf.Br^2))+(mod1.mf.Bz^2))^(-0.5))*0.5))*(1/unit_T_cf))*dmod1.mat2.def.MUR_dx1((sqrt((((mod1.mf.Bphi^2)+(mod1.mf.Br^2))+(mod1.mf.Bz^2)))/unit_T_cf)))))
Failed to evaluate temporary symbolic derivative variable.
- Variable: mod1.mf.Hz@VDN${if@7}
- Defined as: ((1/mu0_const)*((mod1.mf.Bz*((((-1)/(mod1.mf.murzz^2))*(((((mod1.mf.Bz*2)*(((((mod1.mf.Bphi^2)+(mod1.mf.Br^2))+(mod1.mf.Bz^2))^(-0.5))*0.5))*(1/unit_T_cf))*dmod1.mat2.def.MUR_dx1((sqrt((((mod1.mf.Bphi^2)+(mod1.mf.Br^2))+(mod1.mf.Bz^2)))/unit_T_cf)))))))+mod1.mf.murinvzz))
Failed to evaluate expression.
- Expression: d(d((2*(mod1.mf.Hr*test(mod1.Aphiz)-mod1.mf.Hz*(test(mod1.Aphir)+if(abs(r)<0.0010*h,d(test(mod1.Aphi),r),test(mod1.Aphi)/r))+mod1.mf.Jphi*test(mod1.Aphi))*pi*r)*(dvol_spatial),{if@3}),{if@7})
I tried on win32 and win64, same error message.
Does any senior guy understand this information and has a suggestion?
Thanks in advance!
(my comsol ver is 4.1, I added the tag, but seems lost)
I tried the loudspeaker_driver example, I right click on the study1->compute...it began to calculate and then give me an error:
Attempt to evaluate negative power of zero.
- Function: ^
Failed to evaluate temporary symbolic derivative variable.
- Variable: mod1.mf.murzz@VDN${if@7}
- Defined as: ((((mod1.mf.Bz*2)*(((((mod1.mf.Bphi^2)+(mod1.mf.Br^2))+(mod1.mf.Bz^2))^(-0.5))*0.5))*(1/unit_T_cf))*dmod1.mat2.def.MUR_dx1((sqrt((((mod1.mf.Bphi^2)+(mod1.mf.Br^2))+(mod1.mf.Bz^2)))/unit_T_cf)))
Failed to evaluate temporary symbolic derivative variable.
- Variable: mod1.mf.murinvzz@VDN${if@7}
- Defined as: (((-1)/(mod1.mf.murzz^2))*(((((mod1.mf.Bz*2)*(((((mod1.mf.Bphi^2)+(mod1.mf.Br^2))+(mod1.mf.Bz^2))^(-0.5))*0.5))*(1/unit_T_cf))*dmod1.mat2.def.MUR_dx1((sqrt((((mod1.mf.Bphi^2)+(mod1.mf.Br^2))+(mod1.mf.Bz^2)))/unit_T_cf)))))
Failed to evaluate temporary symbolic derivative variable.
- Variable: mod1.mf.Hz@VDN${if@7}
- Defined as: ((1/mu0_const)*((mod1.mf.Bz*((((-1)/(mod1.mf.murzz^2))*(((((mod1.mf.Bz*2)*(((((mod1.mf.Bphi^2)+(mod1.mf.Br^2))+(mod1.mf.Bz^2))^(-0.5))*0.5))*(1/unit_T_cf))*dmod1.mat2.def.MUR_dx1((sqrt((((mod1.mf.Bphi^2)+(mod1.mf.Br^2))+(mod1.mf.Bz^2)))/unit_T_cf)))))))+mod1.mf.murinvzz))
Failed to evaluate expression.
- Expression: d(d((2*(mod1.mf.Hr*test(mod1.Aphiz)-mod1.mf.Hz*(test(mod1.Aphir)+if(abs(r)<0.0010*h,d(test(mod1.Aphi),r),test(mod1.Aphi)/r))+mod1.mf.Jphi*test(mod1.Aphi))*pi*r)*(dvol_spatial),{if@3}),{if@7})
I tried on win32 and win64, same error message.
Does any senior guy understand this information and has a suggestion?
Thanks in advance!
(my comsol ver is 4.1, I added the tag, but seems lost)
2 Replies Last Post Nov 30, 2010, 7:42 a.m. EST
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Posted:
1 decade ago
Hi
What version of Comsol are you using?
the error has something to do with the relative permability (thats called mf.murzz. the syntax is mf = magnetic field, mur = mu relative. zz is something to do with the direction.
so check that the relative permability is specified for all domains.
also the mf module needs a initial field to start... else this can give some divide by zero errors...
check under initial field and make it a function of z or r - or similar... then the derived is also non-zero
Hope this helps.
Best regards
Kim Folmer Andersen
What version of Comsol are you using?
the error has something to do with the relative permability (thats called mf.murzz. the syntax is mf = magnetic field, mur = mu relative. zz is something to do with the direction.
so check that the relative permability is specified for all domains.
also the mf module needs a initial field to start... else this can give some divide by zero errors...
check under initial field and make it a function of z or r - or similar... then the derived is also non-zero
Hope this helps.
Best regards
Kim Folmer Andersen
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Oh, thank you Kim,
the example has defined the permanent magnet with B=mu_0*mu_r*H+Br and other place with B=mu_0*mu_r*H, I don't understand where is the problem and meanwhile it is an example in the document. :-(
the example has defined the permanent magnet with B=mu_0*mu_r*H+Br and other place with B=mu_0*mu_r*H, I don't understand where is the problem and meanwhile it is an example in the document. :-(