# Link error

**URL:** <https://www.ruby-forum.com/t/link-error/233973>\
**Category:** GNU Radio\
**Created:** [January 27, 2015, 2:57pm UTC](https://www.ruby-forum.com/t/link-error/233973 "2015-01-27T14:57:21Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\
**Post date:** [January 27, 2015, 2:57pm UTC](https://www.ruby-forum.com/t/link-error/233973/1 "2015-01-27T14:57:21Z")

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Hi all:  
Thank you in advance.  
I have use the tool “gr\_modtool” to create a cpp document.But  
an error exists:  
ImportError: /usr/local/lib/libgnuradio-mimo.so: undefined  
symbol: \_ZTIN2gr4mimo21csi\_int\_cfo\_vcvc\_implE  
I have search the maillist,and find “sudo ldconfig” to solve it.But when  
I use the “sudo ldconfig”,the error also exists.  
Can someone help me?  
Best regards,  
zs

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**Author:** ![zszszs](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/5fc32e/32.png) [@zszszs](https://www.ruby-forum.com/u/zszszs)\
**Post date:** [January 28, 2015, 3:56pm UTC](https://www.ruby-forum.com/t/link-error/233973/2 "2015-01-28T15:56:19Z")

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Is there a way to use Python’s math.log() in the value field of a  
variable in gnuradio-companion? It seems like I can only use the Python  
built in functions.

//\ark.

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**Author:** ![zszszs](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/5fc32e/32.png) [@zszszs](https://www.ruby-forum.com/u/zszszs)\
**Post date:** [January 28, 2015, 4:00pm UTC](https://www.ruby-forum.com/t/link-error/233973/3 "2015-01-28T16:00:24Z")

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On 01/28/2015 03:54 PM, [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Is there a way to use Pythons math.log() in the value field of a  
> variable in gnuradio-companion? It seems like I can only use the Python  
> built in functions.

AFAIK, there is an Import block in GRC.

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**Author:** ![zszszs](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/5fc32e/32.png) [@zszszs](https://www.ruby-forum.com/u/zszszs)\
**Post date:** [January 28, 2015, 4:06pm UTC](https://www.ruby-forum.com/t/link-error/233973/4 "2015-01-28T16:06:30Z")

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Thanks! That works!

## //\ark.

Aim for brevity while avoiding jargon.  
Edsger Dijkstra