Trouble installing MXNet on Raspberry Pi 3

[FrancisTse8]

Environment info and background:

Raspberry Pi 3 running Raspbian version 9 stretch

On the newly installed Raspbian on a Raspberry Pi 3, followed instructions on https://aws.amazon.com/blogs/ai/build-a-real-time-object-classification-system-with-apache-mxnet-on-raspberry-pi/ to first install the prerequisites:
sudo apt-get update
sudo apt-get install python-pip python-opencv python-scipy python-picamera

After that, I followed the instructions to go to page https://mxnet.incubator.apache.org/get_started/install.html to install MXNet by selecting Devices and Raspberry Pi.

I followed the instructions and did the following:
sudo apt-get update
sudo apt-get -y install git cmake build-essential g++-4.8 c++-4.8 liblapack* libblas* libopencv*
git clone https://github.com/dmlc/mxnet.git --recursive
cd mxnet
make

Build stopped and got an error message.

Error Message:

...
/usr/bin/ld: cannot find -lcblas
collect2: error: ld returned 1 exit status
Makefile:322: recipe for target 'lib/libmxnet.so' failed
make: *** [lib/libmxnet.so] Error 1

What have you tried to solve it?

Thought the problem was just missing a library, so did the following:
pi@raspberrypi:~ $ sudo apt-get install libcblas*

Ran make again and got further (now have libmxnet.so generated). However, got another error.

New Error Message:

/usr/bin/ld: build/src/operator/tensor/la_op.o: undefined reference to symbol 'cblas_dtrsm'
//usr/lib/libblas.so.3: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
Makefile:344: recipe for target 'bin/im2rec' failed
make: *** [bin/im2rec] Error 1

Steps to reproduce

Will get the same error each time I run make again.

Need Help

Now, I do not know what to do. Has anyone else come across the same problem. Any suggestions for a solution?

[szha]

@arank

[arank]

It looks like the linker isn't finding cblas you may need to manually add the path to the makefile. Also it looks like someone may have pushed a breaking change for our ARM/Rpi build to our makefile @szha ...

[FrancisTse8]

How do I manually add path to cblas in the makefile?

[szha]

@arank who's fixing it?

[FrancisTse8]

I have been poking around, looking at the makefile and trying to figure where cblas is installed. This appears to be a lot more complex than I imagined. In the meantime, I just realized that I am using the brand new Stretch version of Raspbian. Don't know if the make had ever been tested with Stretch. Could that be the reason why I have trouble with the installation?

[arank]

I would follow the setup guide on mxnet.io exactly, using the Raspbian Jessie version. @szha I am currently traveling w/ no access to a Pi but I can take a look once I am back.

[FrancisTse8]

@arank and @szha thanks. I've just created a Jessie version and will try following the process again. Will report what I found.

[larroy]

You can use our docker files to build for arm, we build against or own blas.

It should work:

https://github.com/larroy/mxnet/tree/master/docker

[FrancisTse8]

##Okay, I got jessie running on a Raspberry Pi 3
But, when I do:
pi@raspberrypi:~ $ sudo apt-get -y install git cmake build-essential g++-4.8 c++-4.8 liblapack* libblas* libopencv*

##I got the following error:
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
liblapack3 : Breaks: liblapack3gf
E: Unable to correct problems, you have held broken packages.

How can I resolve the dependencies? I know this is not a MXNet issue as such. I am new at this. Any help is much appreciated. BTW, thanks @larroy. I am hoping the issue is with Stretch. Will have to look at your docker approach as backup plan.

[arank]

Stack overflow is usually a good place to start w/ these more general questions about more general deb package management... try looking at this answer https://askubuntu.com/questions/563178/the-following-packages-have-unmet-dependencies

[FrancisTse8]

Found out from Sébastien Villemot sebastien@debian.org that I have correctly installed LAPACK (shared library, doc and development libraries) and also ATLAS (shared library). Issue is that I gave a wildcard (liblapack*) to apt-get, so it also tried to install virtual packages (like liblapack3gf), which no longer exists but only appears in a Breaks relationship.

So, I continued with the MXNet installation by doing:

sudo apt-get update
sudo apt-get -y install git cmake build-essential g++-4.8 c++-4.8 liblapack* libblas* libopencv*
git clone https://github.com/dmlc/mxnet.git --recursive
cd mxnet
make

However, I got the same error as when I was using Stretch version of Raspbian:

/usr/bin/ld: cannot find -lcblas
collect2: error: ld returned 1 exit status
Makefile:327: recipe for target 'lib/libmxnet.so' failed
make: *** [lib/libmxnet.so] Error 1

I was going to try loading the cblas library again but this time I got message that libcblas* or libcblas could not be found:

pi@raspberrypi:~/mxnet $ sudo apt-get install libcblas*
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package libcblas*
E: Couldn't find any package by regex 'libcblas*'
pi@raspberrypi:~/mxnet $ sudo apt-get install libcblas
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package libcblas

So it appears make would not work for Raspbian jessie as well. @arank, guess I will have to wait for you to take a look at the issue when you can. Thanks.

[FrancisTse8]

Oops, don't know why some of the text were crossed out. Please ignore. Did not mean to cross anything out.

[arank]

Thanks for testing this out. I will take a look next week but in the mean time the docker based solution from @larroy should help you get around this since all the dependencies are self contained and it is built against ARMv7.

[szha]

@FrancisTse8 markdown supports verbatim code blocks. I edited your comment above. Click edit again to see how it's written

[FrancisTse8]

Cool! @szha, thanks for the tip.